Pots splitter assembly with improved transhybrid loss for digital subscriber loop transmission

• US 5,757,803 A
• Filed: 11/27/1995
• Issued: 05/26/1998
• Est. Priority Date: 11/27/1995
• Status: Expired due to Term

• Current Assignee: Ikanos Communications Incorporated (Qualcomm, Inc.)
• Original Assignee: Analog Devices, Inc.
• Inventors: Russell, Mark A., Ribner, David B.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): PHILLIPS, MATTHEW
• Application Number:
  US08/562,981
• Time in Patent Office: 911 Days
• Field of Search: 370/493, 370/494, 370/495, 370/496, 370/497, 370/480, 370/488, 379/402, 379/405
• US Class Current: 370/494
• CPC Class Codes: H04M 11/062 using different frequency bands for speech and other data
• CPC Class Codes: H04Q 2213/13034 A/D conversion, code compression/expansion
• CPC Class Codes: H04Q 2213/13174 Data transmission, file transfer
• CPC Class Codes: H04Q 2213/1319 Amplifier, attenuation circuit, echo suppressor
• CPC Class Codes: H04Q 2213/13199 Modem, modulation
• CPC Class Codes: H04Q 2213/13305 Transistors, semiconductors in general
• CPC Class Codes: H04Q 2213/1332 Logic circuits

Abstract

A data transmission system including a telephone service subscriber loop utilized for transmission of data including telephone service signals; a splitter operable for splitting the subscriber loop into a first transmission path including a low pass filter which accommodates a continuation of telephone service signal transmissions along the subscriber loop and a second transmission path, said second transmission path including a capacitive element for attenuating the telephone service signals; and a digital subscriber loop transceiver coupled to the second transmission path for implementing high rate digital data transmission over the subscriber loop, the transceiver including a frontend processing circuit having a transmit path and a receive path, at least said receive path comprising a high pass filter for further attenuating said telephone service signals. The capacitive element in the second transmission path and the high pass filter in the receive path of the transceiver frontend operate in conjunction to maintain transhybrid loss.

Claims

1. A data transmission system comprising:

a telephone service subscriber loop utilized for transmission of data including telephone service signals;

a splitter operable for splitting the subscriber loop into a first transmission path including a low pass filter which accommodates a continuation of telephone service signal transmissions along said subscriber loop and a second transmission path, said second transmission path including a first high pass filter for attenuating said telephone service signals; and

a digital subscriber loop transceiver coupled to said second transmission path for implementing high rate digital data transmission over said subscriber loop, wherein

said transceiver includes a hybrid circuit, and wherein a second high pass filter is added in series with a hybrid matching circuit of said hybrid circuit in order to maintain transhybrid loss relative to the case where said first high pass filter is not utilized.

2. The system of claim 1, wherein said transceiver includes a frontend processing circuit which incorporates said hybrid circuit and has a transmit path and a receive path, said receive path of said frontend processing circuit including a third high pass filter which further attenuates said telephone service signals, said third high pass filter serving to reduce the complexity of said first and second high pass filters.

3. The system of claim 2, wherein said transmit path of said frontend processing circuit includes a fourth high pass filter which attenuates signals transmitted by said transceiver in order to avoid interference with said telephone service signals.

4. The system of claim 1, wherein said hybrid matching circuit and said second high pass filter in series with said hybrid matching circuit each have a series capacitor whose placement allows the two to be combined into a single capacitor with a predetermined value.

5. The system of claim 4, wherein said first and second high pass filters comprise series capacitors, thus allowing the series combination of said hybrid matching circuit and said second high pass filter to be implemented using said hybrid matching circuit with an appropriate reduction of the series capacitor value.

6. The system of claim 5, wherein said series capacitors of said first high pass filter operate in conjunction with termination resistors associated with said transceiver as a first order RC filter between said telephone service subscriber loop and said transceiver.

7. The system of claim 1, wherein said transceiver includes a frontend processing circuit having a transmit path and a receive path, said frontend processing circuit including said hybrid circuit operable for coupling said transmit and receive paths to said telephone service subscriber loop, said hybrid circuit comprising hybrid matching circuit which approximates the impedance associated with both said subscriber loop and said first high pass filter, said matching circuit including a series capacitor which is reduced in value from a predetermined value so as to approximate the resultant impedance associated with said first high pass filter.

8. The system of claim 1, wherein said digital subscriber loop transceiver comprises an asymmetric digital subscriber loop (ADSL) transceiver.

9. The system of claim 1, wherein said digital subscriber loop transceiver comprises a high-rate digital subscriber loop (HDSL) transceiver.

10. The system of claim 1, wherein said digital subscriber loop transceiver comprises a very high-rate digital subscriber loop (VDSL) transceiver.

11. The system of claim 1, wherein said second high pass filter is identical to said first high pass filter.

12. The system of claim 1, wherein said second high pass filter has the same structure as said first high pass filter with component values which are scaled relative to said first high pass filter.

13. A data transmission system comprising:

a telephone service subscriber loop utilized for transmission of data including telephone service signals;

a splitter operable for splitting the subscriber loop into a first transmission path including a low pass filter which accommodates a continuation of telephone service signal transmissions along said subscriber loop and a second transmission path, said second transmission path including a capacitive element for attenuating said telephone service signals; and

a digital subscriber loop transceiver coupled to said second transmission path for implementing high rate digital data transmission over said subscriber loop, said transceiver including a frontend processing circuit having a transmit path and a receive path, said receive path comprising a high pass filter for further attenuating said telephone service signals, wherein said capacitive element in said second transmission path and

said high pass filter in said receive path of said transceiver frontend operate in conjunction to attenuate telephone service signals and allow transhybrid loss to be maintained relative to the case where said capacitive element is not utilized without any additional components in said transceiver.

14. The system of claim 13, wherein said transmit path of said frontend processing circuit includes a second high pass filter which attenuates signals transmitted by said transceiver in order to avoid interference with said telephone service signals.

15. The system of claim 13, wherein said capacitive element comprises a pair of series capacitors in the line between said telephone service subscriber loop and said transceiver.

16. The system of claim 15, wherein said pair of series capacitors operate as a first order RC high pass filter between said telephone service subscriber loop and said transceiver.

17. The system of claim 13, wherein said transceiver includes a frontend processing circuit having a transmit path and a receive path, said frontend processing circuit including a hybrid circuit operable for coupling said transmit and receive paths to said telephone service subscriber loop, said hybrid circuit comprising a matching circuit which approximates the impedance associated with both said subscriber loop and said capacitive element, said matching circuit including a series capacitor which is reduced in value from a predetermined value so as to approximate the resultant impedance associated with said capacitive element.

18. The system of claim 13, wherein said digital subscriber loop transceiver comprises an asymmetric digital subscriber loop (ADSL) transceiver.

19. The system of claim 13, wherein said digital subscriber loop transceiver comprises a high-rate digital subscriber loop (HDSL) transceiver.

20. The system of claim 13, wherein said digital subscriber loop transceiver comprises a very high-rate digital subscriber loop (VDSL) transceiver.

21. A data transmission system comprising:

a telephone service subscriber loop utilized for transmission of data including telephone service signals;

a splitter operable for splitting the subscriber loop into a first transmission path including a low pass filter which accommodates a continuation of telephone service signal transmissions along said subscriber loop and a second transmission path including a first high pass filter for attenuating said telephone service signals; and

a digital subscriber loop transceiver coupled to said second transmission path for implementing high rate digital data transmission over said subscriber loop, said transceiver including a frontend processing circuit having a transmit path and a receive path coupled to said splitter via a hybrid circuit, said hybrid circuit including an impedance matching circuit and a second high pass filter in series, wherein

said second high pass filter and said impedance matching circuit operate in conjunction to maintain transhybrid loss relative to the case where said first high pass filter is not utilized.

22. The system of claim 21, wherein said digital subscriber loop transceiver comprises an asymmetric digital subscriber loop (ADSL) transceiver.

23. The system of claim 21, wherein said digital subscriber loop transceiver comprises a high-rate digital subscriber loop (HDSL) transceiver.

24. The system of claim 21, wherein said digital subscriber loop transceiver comprises a very high-rate digital subscriber loop (VDSL) transceiver.