Digital compressed voice paging system which uses R.D.S. format for the ID signals and S.C.A. format for the voice signals both formats being FM subcarriers
First Claim
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1. A paging system using at least one subcarrier within an FM channel bandwidth comprising:
- (1) transmitter means comprising;
means for generating an identification signal;
means for converting said identification signal into an encoded identification signal having a first format;
means for transmitting a broadcast identification signal modulated by said encoded identification signal via a first subcarrier of said FM channel;
means for receiving an analog voice signal;
means for converting said analog voice signal to a digital, compressed message signal;
means for converting said digital compressed message signal into an encoded message having a second format; and
,means for transmitting a broadcast message signal modulated by said encoded message signal via a second subcarrier of said FM channel; and
(2) receiver means comprising;
means for receiving said broadcast identification signal to produce an alert signal;
means for receiving said encoded message signal;
decoder means responsive to said alert signal to enable receipt of said encoded message signal;
means for storing said encoded message signal;
means for generating an output enable signal;
means for converting said encoded message signal to an uncompressed analog voice signal in response to said output enable signal, and,means for outputting said uncompressed analog voice signal.
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Abstract
The present invention is a digital FM voice paging system which uses digital signal processing (including D/A conversion and data compression) to transmit voice pager data over existing FM broadcast subcarrriers.
41 Citations
17 Claims
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1. A paging system using at least one subcarrier within an FM channel bandwidth comprising:
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(1) transmitter means comprising; means for generating an identification signal; means for converting said identification signal into an encoded identification signal having a first format; means for transmitting a broadcast identification signal modulated by said encoded identification signal via a first subcarrier of said FM channel; means for receiving an analog voice signal; means for converting said analog voice signal to a digital, compressed message signal; means for converting said digital compressed message signal into an encoded message having a second format; and
,means for transmitting a broadcast message signal modulated by said encoded message signal via a second subcarrier of said FM channel; and (2) receiver means comprising; means for receiving said broadcast identification signal to produce an alert signal; means for receiving said encoded message signal; decoder means responsive to said alert signal to enable receipt of said encoded message signal; means for storing said encoded message signal; means for generating an output enable signal; means for converting said encoded message signal to an uncompressed analog voice signal in response to said output enable signal, and, means for outputting said uncompressed analog voice signal. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A paging system using subcarriers within a commercial FM channel bandwidth comprising:
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(1) transmitter means comprising; means for generating an identification signal; means for converting said identification signal into an encoded identification signal having a Radio Data Services (RDS) standard format; means for transmitting a broadcast identification signal modulated by said encoded identification signal; means for receiving an analog voice signal; means for processing said analog voice signal to produce a compressed digital message signal; means for converting said compressed digital message signal into an encoded message signal having a Sub-Carrier Administration (SCA) standard format; means for transmitting a broadcast message signal modulated by said encoded message signal; and
,(2) receiver means comprising; means for receiving said broadcast identification signal to produce a received identification signal; means for decoding said received identification signal to produce an alert signal; means for decoding said received identification signal, said means responsive to said alert signal to enable receipt of said broadcast message signal to produce a received message signal; means for decoding said received message signal to produce said compressed digital message signal; means for storing at least one of said compressed digital message signals; means for generating an output enable signal; means for processing said stored compressed digital signal, said means responsive to said output enable signal to produce an analog, voice signal; and
,means for outputting said voice signal. - View Dependent Claims (8)
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9. A method of communicating data at a high data rate using at least one subcarrier within an FM channel bandwidth, comprising the steps of:
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receiving an identification signal; receiving an analog voice signal; digitally encoding said signals to transform said signals into an encoded identification signal and an encoded digitally compressed voice signal in accordance with at least one FM subcarrier format; transmitting said encoded identification and digitally compressed voice signals via at least two FM subcarriers according to the following substeps; (a) providing a first signal having a first predetermined frequency to define a first subcarrier; (b) modulating said first subcarrier with said encoded identification signal; (c) providing a second signal having a second predetermined frequency to define a second subcarrier (d) modulating said second subcarrier with said encoded digitally compressed voice signal (e) providing a third signal having a predetermined frequency defining a carrier signal for a said FM channel; and (f) frequency modulating said modulated first and second subcarriers on said carrier signal, said frequency modulated carrier signal being coupled to an antenna for broadcast to a plurality of mobile receiving systems; receiving said encoded signals; storing said receiving signals; retrieving said stored signals. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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Specification