Communication system for coexistent base band and broad band signals
First Claim
1. A communication system comprising:
- a transmission path;
a plurality of first terminal units having means for outputting a corresponding base band signal having frequency components within a base band signal rangea plurality of branch filter means, each being provided for an associated one of said first terminal units, each having a first port, a second port, third port, and a low pass filter means, having a predetermined cut-off frequency, connecting said first port to said second port and connecting said third port to said second port, said associated one of the said first terminal units being connected to said second port, for preventing communication to said transmission path of frequency components of said base band signal above said predetermined cut-off frequency outputted from said associated one of said first terminal units, and said branch filter means having a high pass filter means, within said transmission path, having a lower cut-off frequency above said low pas filter cut-off frequency, connecting said first port to said third port for passing a broad band signal, said broad band signal having a range extending upwards from said lower cut-off frequency, through said transmission path from said first port to said third port;
a plurality of second terminal units each having means for sending out a first modulated signal having a first frequency range and means for receiving a second modulated signal having a second frequency range, said first and second frequency ranges being higher than the cut-off frequency of said lowpass filter means, a part of a lower one of said first and second frequency ranges being overlapped with the higher frequency components of said base band signal cut off by said lowpass filter means; and
a plurality branch connecting means, each being provided for an associated one of said second terminal units, for connecting said associated one of said second terminal units to said transmission path.
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Abstract
A base-band and broad-band coexisting communication system comprises a transmission path, a plurality of first data terminal units outputting data to be transmitted in the form of pulse signals (base band signals), a plurality of second data terminal units for outputting data to be transmitted in the form of modulated signals (broad band signals) each having a center frequency within a predetermined frequency range, and a plurality of low-pass filters, each connected to each of the first data transmission units, for cutting off high frequency components of the base band signal outputted by the first data terminal device at a predetermined cut-off frequency which does not overlap with the broad band signals.
71 Citations
8 Claims
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1. A communication system comprising:
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a transmission path; a plurality of first terminal units having means for outputting a corresponding base band signal having frequency components within a base band signal range a plurality of branch filter means, each being provided for an associated one of said first terminal units, each having a first port, a second port, third port, and a low pass filter means, having a predetermined cut-off frequency, connecting said first port to said second port and connecting said third port to said second port, said associated one of the said first terminal units being connected to said second port, for preventing communication to said transmission path of frequency components of said base band signal above said predetermined cut-off frequency outputted from said associated one of said first terminal units, and said branch filter means having a high pass filter means, within said transmission path, having a lower cut-off frequency above said low pas filter cut-off frequency, connecting said first port to said third port for passing a broad band signal, said broad band signal having a range extending upwards from said lower cut-off frequency, through said transmission path from said first port to said third port; a plurality of second terminal units each having means for sending out a first modulated signal having a first frequency range and means for receiving a second modulated signal having a second frequency range, said first and second frequency ranges being higher than the cut-off frequency of said lowpass filter means, a part of a lower one of said first and second frequency ranges being overlapped with the higher frequency components of said base band signal cut off by said lowpass filter means; and a plurality branch connecting means, each being provided for an associated one of said second terminal units, for connecting said associated one of said second terminal units to said transmission path. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A broad band communication system comprising:
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a plurality of information devices for performing broad band communication with each other connected to a transmission path along which modulated signals having a plurality of mutually different frequency ranges, each of said frequency ranges being previously allocated according to kinds of said information devices; a plurality of data processing units for performing base band communication with each other, each having means for outputting digital data in the form of a base band signal having a frequency range, a higher part of which is overlapped with one of said frequency ranges of said modulated signals; and a plurality of branch connecting means, each being provided for an associated one of said data processing units for connecting the associated data processing unit to said transmissional path, each of said branch connecting means including filter means for limiting the frequency range of the base band signal communicated between said associated data processing unit and said transmission path as being within a range outside of the frequency ranges of the broad band signal used by said information devices.
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8. A communication network comprising:
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a transmission path; a plurality of first data processing units for performing base band communication with each other by outputting digital data onto said transmission path in the form of a base band signal, branch connecting means provided between each of said first data processing units and said transmission path for limiting the frequency range of said base band signal inputted/outputted to/from said first data processing unit to a frequency range not higher than a predetermined cut-off frequency, but passing the broad band signal through said transmission path; and a plurality of second data processing units for performing broad band communication by outputting data to be transmitted onto said transmission path after modulation to a predetermined frequency range which is higher than said cutoff frequency. whereby both said base band communication and said broad band communication are performed individually on said transmission path.
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Specification