SSB communication system with FM data capability
First Claim
1. A radio communication system having a primary station and at least one remote station, said primary and remote stations adapted to operate on a plurality of radio frequency channels, said radio communication system comprising:
- said primary station including;
means for transmitting voice messages via a first type of modulation within a first channel of said plurality of channels, said first channel having a predetermined channel bandwidth; and
means for transmitting a first set of data messages via a second type of modulation within a second channel of said plurality of channels, said first set of data messages including receiver control information, said second channel having a predetermined channel bandwidth being no wider than said first channel bandwidth;
and said remote station including;
means for alternatively receiving one of either;
(a) said voice messages; and
(b) said first set of data messages; and
means for automatically controlling said receiving means such that said voice messages are received from said first channel in response to said receiver control information derived from said first set of data messages received from said second channel.
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Accused Products
Abstract
A radio communications system is described in which analog voice signals are transmitted and received via single sideband amplitude modulation, and digital data signals are transmitted and received via narrowband frequency modulation in a single trunked radio system having dedicated channel bandwidths. The base station continuously transmits the FM signalling information on a dedicated control channel. The remote station transceiver initially acquires lock to the data channel FM carrier, which is then demodulated to determine the frequency of an assigned voice channel. The remote station then acquires lock to the single sideband pilot carrier on the appropriate voice channel. The controller incorporates a memory state for holding AFC for the mobile transmit frequency. In the preferred embodiment, the data channel incorporates 2400 bps FSK-FM data in a 6.25 KHz channel bandwidth, while the voice channel includes a reduced pilot carrier located below the voice band for AFC and AGC reference, and an audio subcarrier located above the voice band for low speed FM data within the same 6.25 KHz channel bandwidth.
89 Citations
51 Claims
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1. A radio communication system having a primary station and at least one remote station, said primary and remote stations adapted to operate on a plurality of radio frequency channels, said radio communication system comprising:
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said primary station including; means for transmitting voice messages via a first type of modulation within a first channel of said plurality of channels, said first channel having a predetermined channel bandwidth; and means for transmitting a first set of data messages via a second type of modulation within a second channel of said plurality of channels, said first set of data messages including receiver control information, said second channel having a predetermined channel bandwidth being no wider than said first channel bandwidth; and said remote station including; means for alternatively receiving one of either;
(a) said voice messages; and
(b) said first set of data messages; andmeans for automatically controlling said receiving means such that said voice messages are received from said first channel in response to said receiver control information derived from said first set of data messages received from said second channel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A radio communication system having a base station transceiver and a plurality of remote station transceivers, each of said base and remote station transceivers adapted to transmit and receive voice and data signals over any one of a plurality of communications channels, said radio communication system comprising:
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said base station transceiver including; means for transmitting a given frequency band of voice signals via single sideband (SSB) amplitude modulation (AM) within a first channel of said plurality of channels, said first channel having a predetermined channel bandwidth, said SSB-AM including an audio subcarrier located outside said voice band; means for modulating low speed data signals on said first channel audio subcarrier within said first channel bandwidth; means for transmitting high speed data signals via narrowband frequency modulation (FM) within a second channel of said plurality of channels, said second channel having a predetermined channel bandwidth being no wider than said first channel bandwidth; and each of said remote station transceivers including; means for selectively receiving one of either;
(a) said SSB-AM voice signals; and
(b) said narrowband FM high speed data signals;means for decoding information contained in said received high speed data signals to provide a first receiver control signal; and means responsive to said first receiver control signal for automatically selecting one of said plurality of channels to be received by said remote station receiving means. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method of communicating via radio frequency signals in a radio communication system having a primary station and a plurality of remote stations, said primary station adapted to transmit and each of said remote stations adapted to receive voice and data signals over a plurality of communications channels, said communicating method comprising the steps of:
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(a) transmitting voice signals from said primary station via single sideband (SSB) amplitude modulation (AM) within a first channel of said plurality of channels, said first channel having a predetermined channel bandwidth; (b) transmitting a first set of data signals, having receiver control information encoded therein, from said primary station via narrowband frequency modulation (FM) within a second channel of said plurality of channels, said second channel having a predetermined channel bandwidth being no wider than said first channel bandwidth; (c) alternatively receiving in at least one of said remote stations one of either;
(1) said SSB-AM voice signals; and
(2) said narrowband FM data signals;(d) decoding said receiver control information from said received FM data signals to provide a receiver control signal; and (e) automatically selecting a particular channel to be received by said remote station in response to said receiver control signal. - View Dependent Claims (36, 37, 38, 39, 40, 41)
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42. A method of receiving radio frequency signals in a radio communication system having a primary station and a plurality of remote stations, said primary station adapted to transmit and each of said remote stations adapted to receive voice and data transmissions over a plurality of communications channels, said receiving method comprising the steps of:
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(a) alternatively receiving in at least one of said remote stations one of either; (1) voice signals transmitted via single sideband (SSB) amplitude modulation (AM) within a first channel having a predetermined channel bandwidth; and (2) a first set of data signals, having receiver control information encoded therein, transmitted via narrowband frequency modulation (FM) within a second channel of said plurality of channels, said second channel having a predetermined channel bandwidth being no wider than said first channel bandwidth; (b) decoding said receiver control information from said received FM data signals to provide a receiver control signal; and (c) automatically selecting a particular channel to be received by said remote station in response to said receiver control signal. - View Dependent Claims (43, 44, 45, 46, 47, 48)
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49. A method of radio frequency signal transmission in a radio communication system having a primary station and a plurality of remote stations, said primary and remote stations adapted to transmit and receive voice and data signals over a plurality of communications channels, said transmission method comprising the steps of:
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(a) receiving in at least one of said remote stations a first set of data signals transmitted from said primary station; (b) decoding said received data signals to provide a transceiver control signal; (c) alternatively transmitting from said remote station one of either; (1) voice signals via single sideband (SSB) amplitude modulation (AM) within a first channel of said plurality of channels, said first channel having a predetermined channel bandwidth; and (2) a second set of data signals vis narrowband frequency modulation (FM) within a second channel of said plurality of channels, said second channel having a predetermined channel bandwidth being no wider than said first channel bandwidth; and (d) automatically selecting a particular channel to be transmitted by said remote station in response to said transceiver control signal. - View Dependent Claims (50, 51)
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Specification