Optical transmission apparatus

• US 20030002125A1
• Filed: 06/28/2002
• Published: 01/02/2003
• Est. Priority Date: 06/28/2001
• Status: Abandoned Application

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Fuse, Masaru
• Application Number:
  US10/183,170
• Publication Number:
  US 20030002125A1
• Time in Patent Office: Days
• US Class Current: 359/238
• CPC Class Codes: H04Q 11/04 for time-division multiplexing H04Q11/0001 takes precedence
• CPC Class Codes: H04Q 2213/1301 Optical transmission, optical switches
• CPC Class Codes: H04Q 2213/13038 Optical modulation
• CPC Class Codes: H04Q 2213/13039 Asymmetrical two-way transmission, e.g. ADSL, HDSL
• CPC Class Codes: H04Q 2213/13099 Loop multiplexer
• CPC Class Codes: H04Q 2213/13291 Frequency division multiplexing, FDM

Abstract

In a transmission apparatus 8, modulation sections 201 convert digital data signals into DSL modulated signals, which are thereafter subjected to frequency conversion so as to span respectively different frequency bands. A combination section 207 frequency-division-multiplexes output signals from the modulation sections 201. An optical modulation section 102 converts the frequency-division-multiplexed signal into an optical signal. An optical detection section 104 reconverts the optical signal which has been transmitted over the optical transmission section 103 into an electrical signal. A splitter section 408 demultiplexes the electrical signal. Each of second frequency conversion sections 811 subjects either one of the demultiplexed signals to frequency conversion, and sends a resultant DSL modulated signal onto an electrical transmission section 105. The DSL demodulation section 106 reconverts the DSL modulated signal which has been transmitted over the electrical transmission section 105 into the original digital data signal.

Claims

1. A transmission apparatus for providing a DSL (Digital Subscriber Line) service, comprising:

a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal;

an optical modulation section for converting the DSL modulated signal outputted from the DSL modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the DSL modulated signal, the DSL modulated signal being an electrical signal;

an electrical transmission section for transmitting the DSL modulated signal outputted from the optical detection section; and

a DSL demodulation section for demodulating the DSL modulated signal transmitted over the electrical transmission section to reproduce the digital data signal.

15. The transmission apparatus according to claim 1, wherein the DSL modulated signal is one selected from the group consisting of:

a signal modulated by DMT (Discrete Multi Tone) modulation technique, a signal modulated by CAP (Carrierless Amplitude/Phase modulation) modulation technique, and a signal modulated by QAM (Quadrature Amplitude Modulation) modulation technique.

18. The transmission apparatus according to claim 1, wherein the electrical transmission section comprises a twisted-pair cable or a coaxial cable.

2. A transmission apparatus for providing a DSL service, comprising:

a modulation section including a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band;

an optical modulation section for converting a signal outputted from the modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

an electrical transmission section for transmitting the electrical signal outputted from the optical detection section; and

a demodulation section including a second frequency conversion section for subjecting the electrical signal transmitted over the electrical transmission section to a frequency conversion so as to span a predetermined second frequency band, and a DSL demodulation section for demodulating a signal outputted from the second frequency conversion section to reproduce the digital data signal.

12. The transmission apparatus according to claim 2, wherein the second frequency band is a frequency band spanned by the DSL modulated signal.

3. A transmission apparatus for providing a DSL service, comprising:

a modulation section including a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band;

an optical modulation section for converting a signal outputted from the modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a second frequency conversion section for subjecting a signal outputted from the optical detection section to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section; and

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signal.

13. The transmission apparatus according to claim 3, wherein the second frequency band is a frequency band spanned by the DSL modulated signal.

16. The transmission apparatus according to claim 3, wherein the DSL modulated signal is one selected from the group consisting of:

a signal modulated by DMT modulation technique, a signal modulated by CAP modulation technique, and a signal modulated by QAM modulation technique.

19. The transmission apparatus according to claim 3, wherein the electrical transmission section comprises a twisted-pair cable or a coaxial cable.

4. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM (Frequency Division Multiplexed) signal;

an optical modulation section for converting the FDM signal outputted from the combination section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the FDM signal, the FDM signal being an electrical signal;

an electrical transmission section for transmitting the FDM signal outputted from the optical detection section; and

a demodulation section including a second frequency conversion section for selecting one of the M signals contained in the FDM signal transmitted over the electrical transmission section and subjecting the selected signal to frequency conversion so as to span a predetermined second frequency band, and a DSL demodulation section for demodulating a signal outputted from the second frequency conversion section to reproduce the digital data signal.

5. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

an optical modulation section for converting the FDM signal outputted from the combination section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the FDM signal, the FDM signal being an electrical signal;

a second frequency conversion section for selecting one of the M signals contained in the FDM signal outputted from the optical detection section, and subjecting the selected signal to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section; and

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signal.

6. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

an optical modulation section for converting the FDM signal outputted from the combination section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the FDM signal, the FDM signal being an electrical signal;

a branching section for branching the FDM signal outputted from the optical detection section into N FDM signals (where N is an integer equal to or greater than two);

N electrical transmission sections provided respectively corresponding to the N FDM signals outputted from the branching section for transmitting the respective branched-out FDM signals;

N demodulation sections provided respectively corresponding to the N electrical transmission sections, each including a second frequency conversion section for selecting one of the M signals contained in the FDM signal transmitted over the respective electrical transmission section and subjecting the selected signal to frequency conversion so as to span a predetermined second frequency band, and a DSL demodulation section for demodulating a signal outputted from the second frequency conversion section to reproduce the digital data signal.

9. The transmission apparatus according to claim 6, wherein M is equal to N.

7. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

an optical modulation section for converting the FDM signal outputted from the combination section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the FDM signal, the FDM signal being an electrical signal;

a splitter section for extracting L different signals (where L is an integer equal to or greater than two and equal to or smaller than M) from among the M signals contained in the FDM signal outputted from the optical detection section, the L different signals being separately outputted;

L electrical transmission sections provided respectively corresponding to the L signals outputted from the splitter section for transmitting the respective L signals;

L demodulation sections provided respectively corresponding to the L electrical transmission sections, each including a second frequency conversion section for subjecting the signal transmitted over the respective electrical transmission section to frequency conversion so as to span a predetermined second frequency band, and a DSL demodulation section for demodulating a signal outputted from the second frequency conversion section to reproduce the digital data signal.

10. The transmission apparatus according to claim 7, wherein M is equal to L.

8. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

an optical modulation section for converting the FDM signal outputted from the combination section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the FDM signal, the FDM signal being an electrical signal;

a splitter section for extracting L different signals (where L is an integer equal to or greater than two and equal to or smaller than M) from among the M signals contained in the FDM signal outputted from the optical detection section, the L different signals being separately outputted;

L second frequency conversion sections provided respectively corresponding to the L signals outputted from the splitter section, wherein each second frequency conversion section subjects the respective signal to frequency conversion so as to span a predetermined second frequency band;

L electrical transmission sections provided respectively corresponding to the L second frequency conversion sections for transmitting the respective L signals outputted therefrom; and

L DSL demodulation sections provided respectively corresponding to the L electrical transmission sections for demodulating the respective signals transmitted over the respective electrical transmission sections to reproduce the digital data signals.

11. The transmission apparatus according to claim 8, wherein M is equal to L.

14. The transmission apparatus according to claim 8, wherein the second frequency band is a frequency band spanned by each DSL modulated signal.

17. The transmission apparatus according to claim 8, wherein each DSL modulated signal is one selected from the group consisting of:

a signal modulated by DMT modulation technique, a signal modulated by CAP modulation technique, and a signal modulated by QAM modulation technique.

20. The transmission apparatus according to claim 8, wherein each electrical transmission section comprises a twisted-pair cable or a coaxial cable.

21. A transmission apparatus for providing a DSL service, comprising:

a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal;

a first FM modulation section for generating a frequency-modulated signal based on the DSL modulated signal outputted from the DSL modulation section;

an optical modulation section for converting the frequency-modulated signal outputted from the first FM modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the frequency-modulated signal, the frequency-modulated signal being an electrical signal;

a first FM demodulation section for demodulating the frequency-modulated signal outputted from the optical detection section to reproduce the DSL modulated signal;

an electrical transmission section for transmitting the DSL modulated signal outputted from the first FM demodulation section; and

a DSL demodulation section for demodulating the DSL modulated signal transmitted over the electrical transmission section to reproduce the digital data signal.

22. A transmission apparatus for providing a DSL service, comprising:

a modulation section including a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band;

a first FM modulation section for generating a frequency-modulated signal based on a signal outputted from the modulation section;

an optical modulation section for converting the frequency-modulated signal outputted from the first FM modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the frequency-modulated signal, the frequency-modulated signal being an electrical signal;

a first FM demodulation section for demodulating the frequency-modulated signal outputted from the optical detection section to reproduce the signal outputted from the modulation section;

a second frequency conversion section for subjecting a signal outputted from the first FM demodulation section to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section; and

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signal.

28. The transmission apparatus according to claim 27, wherein the respective optical detection sections, the respective second frequency conversion sections, the respective electrical transmission sections, and the respective DSL demodulation sections select to process signals spanning respectively different frequency bands from among the M signals contained in the FDM signal resulting from the reconversion by the optical detection section.

23. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a first combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

a first FM modulation section for generating a frequency-modulated signal based on the FDM signal outputted from the first combination section;

an optical modulation section for converting the frequency-modulated signal outputted from the first FM modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the frequency-modulated signal, the frequency-modulated signal being an electrical signal;

a first FM demodulation section for demodulating the frequency-modulated signal outputted from the optical detection section to reproduce the FDM signal;

a second frequency conversion section for selecting one of the M signals contained in the FDM signal outputted from the first FM demodulation section and subjecting the selected signal to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section; and

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signal.

24. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a first combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

a first FM modulation section for generating a frequency-modulated signal based on the FDM signal outputted from the first combination section;

an optical modulation section for converting the frequency-modulated signal outputted from the first FM modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into the frequency-modulated signal, the frequency-modulated signal being an electrical signal;

a first FM demodulation section for demodulating the frequency-modulated signal outputted from the optical detection section to reproduce the FDM signal;

a splitter section for extracting L different signals (where L is an integer equal to or greater than two and equal to or smaller than M) from among the M signals contained in the FDM signal outputted from the first FM demodulation section, the L different signals being separately outputted;

L second frequency conversion sections provided respectively corresponding to the L signals outputted from the splitter section, wherein each second frequency conversion section subjects the respective signal to frequency conversion so as to span a predetermined second frequency band;

L electrical transmission sections provided respectively corresponding to the L second frequency conversion sections for transmitting the respective L signals outputted therefrom; and

L DSL demodulation sections provided respectively corresponding to the L electrical transmission sections for demodulating the respective signals transmitted over the respective electrical transmission sections to reproduce the digital data signals.

25. A transmission apparatus for providing a DSL service, comprising:

a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal;

an optical modulation section for converting the DSL modulated signal outputted from the DSL modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical distribution section for distributing the optical signal transmitted over the optical transmission section as a plurality of optical signals;

a plurality of optical detection sections provided respectively corresponding to the plurality of optical signals outputted from the optical distribution section for reconverting each of the distributed optical signals into the DSL modulated signal, the DSL modulated signal being an electrical signal;

a plurality of electrical transmission sections provided respectively corresponding to the plurality of optical detection sections for transmitting the respective DSL modulated signals outputted therefrom; and

a plurality of DSL demodulation sections provided respectively corresponding to the plurality of electrical transmission sections for demodulating the respective DSL modulated signals transmitted over the respective electrical transmission sections to reproduce the digital data signal.

26. A transmission apparatus for providing a DSL service, comprising:

a modulation section including a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band;

an optical modulation section for converting a signal outputted from the modulation section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical distribution section for distributing the optical signal transmitted over the optical transmission section as a plurality of optical signals;

a plurality of optical detection sections provided respectively corresponding to the plurality of optical signals outputted from the optical distribution section for reconverting each of the distributed optical signals into an electrical signal;

a plurality of second frequency conversion sections provided respectively corresponding to the plurality of optical detection sections, wherein each second frequency conversion section subjects the signal outputted from the respective optical detection section to frequency conversion so as to span a predetermined second frequency band;

a plurality of electrical transmission sections provided respectively corresponding to the plurality of second frequency conversion sections for transmitting the respective signals outputted therefrom; and

a plurality of DSL demodulation sections provided respectively corresponding to the plurality of electrical transmission sections for demodulating the respective signals transmitted over the respective electrical transmission sections to reproduce the digital data signal.

27. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

an optical modulation section for converting the FDM signal outputted from the combination section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical distribution section for distributing the optical signal transmitted over the optical transmission section as a plurality of optical signals;

a plurality of optical detection sections provided respectively corresponding to the plurality of optical signals outputted from the optical distribution section for reconverting each of the distributed optical signals into the FDM signal, the FDM signal being an electrical signal;

a plurality of second frequency conversion sections provided respectively corresponding to the plurality of optical detection sections, wherein each second frequency conversion section selects one of the M signals contained in the FDM signal outputted from the respective optical detection section, and subjects the selected signal to frequency conversion so as to span a predetermined second frequency band;

a plurality of electrical transmission sections provided respectively corresponding to the plurality of second frequency conversion sections for transmitting the respective signals outputted therefrom;

a plurality of DSL demodulation sections provided respectively corresponding to the plurality of electrical transmission sections for demodulating the respective signals transmitted over the respective electrical transmission sections to reproduce the digital data signals.

29. A transmission apparatus for providing a DSL service, comprising:

a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal;

a frequency division multiplex section for multiplexing a predetermined second electrical signal onto the DSL modulated signal outputted from the DSL modulation section;

an optical modulation section for converting a signal outputted from the frequency division multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating the DSL modulated signal from the second electrical signal in the electrical signal outputted from the optical detection section;

an electrical transmission section for transmitting the DSL modulated signal outputted from the frequency separation section;

a DSL demodulation section for demodulating the DSL modulated signal transmitted over the electrical transmission section to reproduce the digital data signal.

30. A transmission apparatus for providing a DSL service, comprising:

a modulation section including a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band;

a frequency division multiplex section for multiplexing a predetermined second electrical signal onto a signal outputted from the modulation section;

an optical modulation section for converting the signal outputted from the frequency division multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating a signal corresponding to the outputted signal from the modulation section from the second electrical signal in the electrical signal outputted from the optical detection section;

a second frequency conversion section for subjecting the signal corresponding to the outputted signal from the modulation section separated by the frequency separation section to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section; and

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signal.

33. The transmission apparatus according to claim 30, wherein the second electrical signal is a base-band digital data signal.

35. The transmission apparatus according to claim 30, wherein the second electrical signal is an audio signal.

31. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination/multiplex section for multiplexing the M signals outputted from the M modulation sections to generate an FDM signal, and multiplexing a predetermined second electrical signal onto the FDM signal;

an optical modulation section for converting a signal outputted from the combination/multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating the FDM signal from the second electrical signal in the electrical signal outputted from the optical detection section;

a second frequency conversion section for selecting one of the M signals contained in the FDM signal outputted from the frequency separation section, and subjecting the selected signal to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section; and

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signal.

32. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination/multiplex section for multiplexing the M signals outputted from the M modulation sections to generate an FDM signal, and multiplexing a predetermined second electrical signal onto the FDM signal;

an optical modulation section for converting a signal outputted from the combination/multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating the FDM signal from the second electrical signal in the electrical signal outputted from the optical detection section;

a splitter section for extracting L different signals (where L is an integer equal to or greater than two and equal to or smaller than M) from among the M signals contained in the FDM signal outputted from the frequency separation section, the L different signals being separately outputted;

L second frequency conversion sections provided respectively corresponding to the L signals outputted from the splitter section, wherein each second frequency conversion section subjects the respective signal to frequency conversion so as to span a predetermined second frequency band;

L electrical transmission sections provided respectively corresponding to the L second frequency conversion sections for transmitting the respective L signals outputted therefrom; and

L DSL demodulation sections provided respectively corresponding to the L electrical transmission sections for demodulating the respective signals transmitted over the respective electrical transmission sections to reproduce the digital data signals.

34. The transmission apparatus according to claim 32, wherein the second electrical signal is a base-band digital data signal.

36. The transmission apparatus according to claim 32, wherein the second electrical signal is an audio signal.

37. A transmission apparatus for providing a DSL service, comprising:

a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal;

a first FM modulation section for generating a frequency-modulated signal based on the DSL modulated signal outputted from the DSL modulation section;

a frequency division multiplex section for multiplexing a predetermined second electrical signal onto the frequency-modulated signal outputted from the first FM modulation section;

an optical modulation section for converting a signal outputted from the frequency division multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating the frequency-modulated signal from the second electrical signal in the electrical signal outputted from the optical detection section;

a first FM demodulation section for demodulating the frequency-modulated signal outputted from the frequency separation section to reproduce the DSL modulated signal, the DSL modulated signal being an electrical signal;

an electrical transmission section for transmitting the DSL modulated signal outputted from the first FM demodulation section; and

a DSL demodulation section for demodulating the DSL modulated signal transmitted over the electrical transmission section to reproduce the digital data signal.

38. A transmission apparatus for providing a DSL service, comprising:

a modulation section including a DSL modulation section for generating a DSL modulated signal based on an inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band;

a first FM modulation section for generating a frequency-modulated signal based on a signal outputted from the modulation section;

a frequency division multiplex section for multiplexing a predetermined second electrical signal onto the frequency-modulated signal outputted from the first FM modulation section;

an optical modulation section for converting a signal outputted from the frequency division multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating the frequency-modulated signal from the second electrical signal in the electrical signal outputted from the optical detection section;

a first FM demodulation section for demodulating the frequency-modulated signal outputted from the frequency separation section to reproduce a signal corresponding to the outputted signal from the modulation section;

a second frequency conversion section for subjecting a signal outputted from the first FM demodulation section to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section; and

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signal.

39. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

a first FM modulation section for generating a frequency-modulated signal based on the FDM signal outputted from the combination section;

a frequency division multiplex section for multiplexing a predetermined second electrical signal onto the frequency-modulated signal outputted from the first FM modulation section;

an optical modulation section for converting a signal outputted from the frequency division multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating the frequency-modulated signal from the second electrical signal in the electrical signal outputted from the optical detection section;

a first FM demodulation section for demodulating the frequency-modulated signal outputted from the frequency separation section to reproduce the FDM signal;

a second frequency conversion section for selecting one of the M signals contained in the FDM signal outputted from the first FM demodulation section and subjecting the selected signal to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section; and

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signal.

40. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

a combination section for multiplexing the M signals outputted from the M modulation sections and outputting an FDM signal;

a first FM modulation section for generating a frequency-modulated signal based on the FDM signal outputted from the combination section;

a frequency division multiplex section for multiplexing a predetermined second electrical signal onto the frequency-modulated signal outputted from the first FM modulation section;

an optical modulation section for converting a signal outputted from the frequency division multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating the frequency-modulated signal from the second electrical signal in the electrical signal outputted from the optical detection section;

a first FM demodulation section for demodulating the frequency-modulated signal outputted from the frequency separation section to reproduce the FDM signal;

a splitter section for extracting L different signals (where L is an integer equal to or greater than two and equal to or smaller than M) from among the M signals contained in the FDM signal outputted from the first FM demodulation section, the L different signals being separately outputted;

L second frequency conversion sections provided respectively corresponding to the L signals outputted from the splitter section, wherein each second frequency conversion section subjects the respective signal to frequency conversion so as to span a predetermined second frequency band;

L electrical transmission sections provided respectively corresponding to the L second frequency conversion sections for transmitting the respective L signals outputted therefrom; and

L DSL demodulation sections provided respectively corresponding to the L electrical transmission sections for demodulating the respective signals transmitted over the respective electrical transmission sections to reproduce the digital data signals.

41. A transmission apparatus for providing a DSL service, comprising:

M modulation sections provided respectively corresponding to M digital data signals (where M is an integer equal to or greater than two), each including a DSL modulation section for generating a DSL modulated signal based on the respective inputted digital data signal, and a first frequency conversion section for subjecting the DSL modulated signal outputted from the DSL modulation section to frequency conversion so as to span a predetermined first frequency band, the M modulation sections generating M signals spanning respectively different first frequency bands;

an FDM section for multiplexing a plurality of second electrical signals;

a second FM modulation section for generating a frequency-modulated signal based on a signal outputted from the FDM section;

a combination/multiplex section for multiplexing the M signals outputted from the M modulation sections to generate an FDM signal, and multiplexing the frequency-modulated signal outputted from the second FM modulation section onto the FDM signal;

an optical modulation section for converting a signal outputted from the combination/multiplex section into an optical signal;

an optical transmission section for transmitting the optical signal outputted from the optical modulation section;

an optical detection section for reconverting the optical signal transmitted over the optical transmission section into an electrical signal;

a frequency separation section for separating the FDM signal from the frequency-modulated signal in the electrical signal outputted from the optical detection section;

a second frequency conversion section for selecting one of the M signals contained in the FDM signal outputted from the frequency separation section, and subjecting the selected signal to frequency conversion so as to span a predetermined second frequency band;

an electrical transmission section for transmitting a signal outputted from the second frequency conversion section;

a DSL demodulation section for demodulating the signal transmitted over the electrical transmission section to reproduce the digital data signals;

a second FM demodulation section for demodulating the frequency-modulated signal outputted from the frequency separation section to reproduce the signal outputted from the FDM section; and

an FDM separation section for subjecting a signal outputted from the second FM demodulation section to frequency separation to output the plurality of second electrical signals.

42. A transmission apparatus for realizing one-on-one bi-directional communications between M first communication devices and M second communication devices (where M is an integer equal to or greater than two) using a DSL service, wherein the transmission apparatus transmits a first digital data signal from one of the M first communication devices to a corresponding one of the M second communication devices and transmits a second digital data signal from one of the M second communication devices to a corresponding one of the M first communication devices,

M first DSL modulation sections provided respectively corresponding to the M first communication devices, wherein each first DSL modulation section generates a first DSL modulated signal based on the first digital data signal outputted from the respective first communication device;

M first frequency conversion sections provided respectively corresponding to the M first DSL modulation sections for subjecting the respective first DSL modulated signals outputted from the respective first DSL modulation sections to frequency conversion so as to span respectively different predetermined first frequency bands;

a first combination section for multiplexing the M signals outputted from the M first frequency conversion sections and outputting a first FDM signal;

a first optical modulation section for converting the first FDM signal outputted from the first combination section into an optical signal;

a first optical transmission section for transmitting the optical signal outputted from the first optical modulation section;

a first optical detection section for reconverting the optical signal transmitted over the first optical transmission section into the first FDM signal, the first FDM signal being an electrical signal;

a first splitter section for separately outputting the M signals contained in the first FDM signal outputted from the first optical detection section;

M second frequency conversion sections provided respectively corresponding to the M signals outputted from the first splitter section, wherein each second frequency conversion section subjects the respective separated signal to frequency conversion so as to span a predetermined second frequency band;

M first electrical transmission sections provided respectively corresponding to the M second frequency conversion sections for transmitting the respective signals outputted from the respective second frequency conversion sections;

M first DSL demodulation sections provided respectively corresponding to the M first electrical transmission sections, wherein each first DSL demodulation section demodulates the signal transmitted over the respective first electrical transmission section to reproduce the first digital data signal for output to the corresponding second communication device;

M second DSL modulation sections provided respectively corresponding to the M second communication devices, wherein each second DSL modulation section generates a second DSL modulated signal based on the second digital data signal outputted from the respective second communication device;

M second electrical transmission sections provided respectively corresponding to the M second DSL modulation sections for transmitting the respective second DSL modulated signals outputted from the respective second DSL modulation sections;

M third frequency conversion sections provided respectively corresponding to the M second electrical transmission sections for subjecting the respective second DSL modulated signals transmitted over the respective second electrical transmission sections to frequency conversion so as to span respectively different predetermined third frequency bands;

a second combination section for multiplexing the M signals outputted from the M third frequency conversion sections and outputting a second FDM signal;

a second optical modulation section for converting the second FDM signal outputted from the second combination section into an optical signal;

a second optical transmission section for transmitting the optical signal outputted from the second optical modulation section;

a second optical detection section for reconverting the optical signal transmitted over the second optical transmission section into the second FDM signal, the second FDM signal being an electrical signal;

a second splitter section for separately outputting the M signals contained in the second FDM signal outputted from the second optical detection section;

M fourth frequency conversion sections provided respectively corresponding to the M signals outputted from the second splitter section, wherein each fourth frequency conversion section subjects the respective separated signal to frequency conversion so as to span a predetermined fourth frequency band; and

M second DSL demodulation sections provided respectively corresponding to the M fourth frequency conversion sections, wherein each second DSL demodulation section demodulates the signal outputted from the respective fourth frequency conversion section to reproduce the second digital data signal for output to the corresponding first communication device.

43. A transmission apparatus for realizing one-on-one bi-directional communications between M first communication devices and M second communication devices (where M is an integer equal to or greater than two) using a DSL service, wherein the transmission apparatus transmits a first digital data signal from one of the M first communication devices to a corresponding one of the M second communication devices and transmits a second digital data signal from one of the M second communication devices to a corresponding one of the M first communication devices,

M first modulation/demodulation sections provided respectively corresponding to the M first communication devices, wherein each first modulation/demodulation section generates a first DSL modulated signal based on the first digital data signal outputted from the respective first communication device, and demodulates an inputted second DSL modulated signal to reproduce the respective second digital data signal for output to the corresponding first communication device;

M first separation sections provided respectively corresponding to the M first modulation/demodulation sections, where each first separation section outputs the first DSL modulated signal outputted from the respective first modulation/demodulation section, and outputs the respective inputted second DSL modulated signal to the corresponding first modulation/demodulation section;

M first frequency conversion sections provided respectively corresponding to the M first separation sections for subjecting the respective first DSL modulated signals outputted from the respective first separation sections to frequency conversion so as to span respectively different predetermined first frequency bands;

a first combination section for multiplexing the M signals outputted from the M first frequency conversion sections and outputting a first FDM signal;

a first optical modulation section for converting the first FDM signal outputted from the first combination section into an optical signal;

a first optical transmission section for transmitting the optical signal outputted from the first optical modulation section;

a first optical detection section for reconverting the optical signal transmitted over the first optical transmission section into the first FDM signal, the first FDM signal being an electrical signal;

a first splitter section for separately outputting the M signals contained in the first FDM signal outputted from the first optical detection section;

M second frequency conversion sections provided respectively corresponding to the M signals outputted from the first splitter section, wherein each second frequency conversion section subjects the respective separated signal to frequency conversion so as to span a predetermined second frequency band, thereby obtaining the respective first DSL modulated signal;

M bi-directional electrical transmission sections provided respectively corresponding to the M second communication devices;

M second separation sections provided respectively corresponding to the M second frequency conversion sections, wherein each second separation section transmits the first DSL modulated signal outputted from the respective second frequency conversion section to a corresponding one of the M bi-directional electrical transmission sections, and receives for output the second DSL modulated signal transmitted over the corresponding bi-directional electrical transmission section;

M second modulation/demodulation sections provided respectively corresponding to the M bi-directional electrical transmission sections, wherein each second modulation/demodulation section demodulates the first DSL modulated signal transmitted over the respective bi-directional electrical transmission section to reproduce the respective first digital data signal for output to the corresponding second communication device, and generates the second DSL modulated signal based on the second digital data signal outputted from the second communication device for output to the corresponding bi-directional electrical transmission section;

M third frequency conversion sections provided respectively corresponding to M second separation sections for subjecting the respective second DSL modulated signals outputted from the respective second separation sections to frequency conversion so as to span respectively different predetermined third frequency bands;

a second combination section for multiplexing the M signals outputted from the M third frequency conversion sections and outputting a second FDM signal;

a second optical modulation section for converting the second FDM signal outputted from the second combination section into an optical signal;

a second optical transmission section for transmitting the optical signal outputted from the second optical modulation section;

a second optical detection section for reconverting the optical signal transmitted over the second optical transmission section into the second FDM signal, the second FDM signal being an electrical signal;

a second splitter section for separately outputting the M signals contained in the second FDM signal outputted from the second optical detection section; and

M fourth frequency conversion sections provided respectively corresponding to the M signals outputted from the second splitter section, wherein each fourth frequency conversion section subjects the respective separated signal to frequency conversion so as to span a predetermined fourth frequency band, thereby obtaining the second DSL modulated signal for output to the corresponding first separation section.

45. The transmission apparatus according to claim 43, wherein a frequency band spanned by the first DSL modulated signal outputted from each first modulation/demodulation section and a frequency band spanned by the second DSL modulated signal outputted from each second modulation/demodulation section adjoin each other on a frequency axis.

47. The transmission apparatus according to claim 43, wherein a frequency band spanned by a first signal and a frequency band spanned by a second signal adjoin each other on a frequency axis,

wherein the first signal is defined as the signal obtained by subjecting the first DSL modulated signal outputted from each first modulation/demodulation section to frequency conversion by the first frequency conversion section, and the second signal is defined as the signal obtained by subjecting the second DSL modulated signal outputted from the second modulation/demodulation section corresponding to the first modulation/demodulation section to frequency conversion by the second frequency conversion section.

49. The transmission apparatus according to claim 43, wherein frequency bands spanned by first signals and frequency bands spanned by second signals alternate on a frequency axis,

wherein each first signal is defined as the signal obtained by subjecting the first DSL modulated signal outputted from each first modulation/demodulation section to frequency conversion by the first frequency conversion section, and each second signal is defined as the signal obtained by subjecting the second DSL modulated signal outputted from the second modulation/demodulation section corresponding to the first modulation/demodulation section to frequency conversion by the second frequency conversion section.

44. A transmission apparatus for realizing one-on-one bi-directional communications between M first communication devices and M second communication devices (where M is an integer equal to or greater than two) using a DSL service, wherein the transmission apparatus transmits a first digital data signal from one of the M first communication devices to a corresponding one of the M second communication devices and transmits a second digital data signal from one of the M second communication devices to a corresponding one of the M first communication devices,

M first modulation/demodulation sections provided respectively corresponding to the M first communication devices, wherein each first modulation/demodulation section generates a first DSL modulated signal based on the first digital data signal outputted from the respective first communication device, and demodulates an inputted second DSL modulated signal to reproduce the respective second digital data signal for output to the corresponding first communication device;

M first separation sections provided respectively corresponding to the M first modulation/demodulation sections, where each first separation section outputs the first DSL modulated signal outputted from the respective first modulation/demodulation section, and outputs the respective inputted second DSL modulated signal to the corresponding first modulation/demodulation section;

M first frequency conversion sections provided respectively corresponding to the M first separation sections for subjecting the respective first DSL modulated signals outputted from the respective first separation sections to frequency conversion so as to span respectively different predetermined first frequency bands;

a first combination section for multiplexing the M signals outputted from the M first frequency conversion sections and outputting a first FDM signal;

a first optical modulation section for converting the first FDM signal outputted from the first combination section into a first optical signal;

a bi-directional optical transmission section for transmitting an optical signal in a bi-directional manner;

a first optical combination/splitter section for transmitting the first optical signal outputted from the first optical modulation section to the bi-directional optical transmission section, and receiving and outputting a second optical signal transmitted over the bi-directional optical transmission section;

a second optical combination/splitter section for receiving and outputting the first optical signal transmitted over the bi-directional optical transmission section, and sending the inputted second optical signal onto the bi-directional optical transmission section,

a first optical detection section for reconverting the first optical signal outputted from the second optical combination/splitter section into the first FDM signal, the first FDM signal being an electrical signal;

a first splitter section for separately outputting the M signals contained in the first FDM signal outputted from the first optical detection section;

M second frequency conversion sections provided respectively corresponding to the M signals outputted from the first splitter section, wherein each second frequency conversion section subjects the respective separated signal to frequency conversion so as to span a predetermined second frequency band, thereby obtaining the respective first DSL modulated signal;

M bi-directional electrical transmission sections provided respectively corresponding to the M second communication devices;

M second separation sections provided respectively corresponding to the M second frequency conversion sections, wherein each second separation section transmits the first DSL modulated signal outputted from the respective second frequency conversion section to a corresponding one of the M bi-directional electrical transmission sections, and receives for output the second DSL modulated signal transmitted over the corresponding bi-directional electrical transmission section;

M second modulation/demodulation sections provided respectively corresponding to the M bi-directional electrical transmission sections, wherein each second modulation/demodulation section demodulates the first DSL modulated signal transmitted over the respective bi-directional electrical transmission section to reproduce the respective first digital data signal for output to the corresponding second communication device, and generates the second DSL modulated signal based on the second digital data signal outputted from the second communication device for output to the corresponding bi-directional electrical transmission section;

M third frequency conversion sections provided respectively corresponding to M second separation sections for subjecting the respective second DSL modulated signals outputted from the respective second separation sections to frequency conversion so as to span respectively different predetermined third frequency bands;

a second combination section for multiplexing the M signals outputted from the M third frequency conversion sections and outputting a second FDM signal;

a second optical modulation section for converting the second FDM signal outputted from the second combination section into the second optical signal and outputting the second optical signal to the second optical combination/splitter section;

a second optical detection section for reconverting the second optical signal outputted from the second optical combination/splitter section into the second FDM signal, the second FDM signal being an electrical signal;

a second splitter section for separately outputting the M signals contained in the second FDM signal outputted from the second optical detection section; and

M fourth frequency conversion sections provided respectively corresponding to the M signals outputted from the second splitter section, wherein each fourth frequency conversion section subjects the respective separated signal to frequency conversion so as to span a predetermined fourth frequency band, thereby obtaining the second DSL modulated signal for output to the corresponding first separation section.

46. The transmission apparatus according to claim 44, wherein a frequency band spanned by the first DSL modulated signal outputted from each first modulation/demodulation section and a frequency band spanned by the second DSL modulated signal outputted from each second modulation/demodulation section adjoin each other on a frequency axis.

48. The transmission apparatus according to claim 44, wherein a frequency band spanned by a first signal and a frequency band spanned by a second signal adjoin each other on a frequency axis,

wherein the first signal is defined as the signal obtained by subjecting the first DSL modulated signal outputted from each first modulation/demodulation section to frequency conversion by the first frequency conversion section, and the second signal is defined as the signal obtained by subjecting the second DSL modulated signal outputted from the second modulation/demodulation section corresponding to the first modulation/demodulation section to frequency conversion by the second frequency conversion section.

50. The transmission apparatus according to claim 44, wherein frequency bands spanned by first signals and frequency bands spanned by second signals alternate on a frequency axis,

wherein each first signal is defined as the signal obtained by subjecting the first DSL modulated signal outputted from each first modulation/demodulation section to frequency conversion by the first frequency conversion section, and each second signal is defined as the signal obtained by subjecting the second DSL modulated signal outputted from the second modulation/demodulation section corresponding to the first modulation/demodulation section to frequency conversion by the second frequency conversion section.