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Integrated communications terminal

  • US 5,455,823 A
  • Filed: 10/19/1992
  • Issued: 10/03/1995
  • Est. Priority Date: 11/06/1990
  • Status: Expired due to Term
First Claim
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1. An integrated communications terminal, capable of simultaneously receiving signals over a time-division-multiplexed communications channel and at least one other selectable communications channel, for use with a radio satellite unit, having a message display, an input device, RF electronics with an antenna assembly for receiving signals, the RF electronics for converting a received signal to a selectable intermediate-frequency signal and a time-division-multiplexed intermediate-frequency signal, and a transmitter, responsive to a transmitter frequency command signal, for selecting and adjusting the frequency of a carrier signal, said transmitter, responsive to receipt of a data-modulated signal, for amplifying the data-modulated signal and for transmitting the amplified data-modulated signal, comprising:

  • a selectable channel demodulator, operatively coupled to the RF electronics, responsive to a selectable data rate and frequency command signal and to the selectable intermediate frequency signal, for outputting an in-phase selectable signal and a quadrature-phase selectable signal;

    a selectable channel decoder, operatively coupled to said selectable channel demodulator, for convolutionally decoding the in-phase selectable signal and the quadrature-phase selectable signal as a selectable data signal;

    a time-division multiplexed channel demodulator, operatively coupled to said RF electronics, responsive to a time-division-multiplexed data rate and frequency command signal and to the time-division-multiplexed intermediate-frequency signal, for outputting an in-phase time-division-multiplexed signal and a quadrature-phase time-division-multiplexed signal;

    a time-division-multiplexed channel decoder operatively coupled to said time-division-multiplexed channel demodulator for convolutionally decoding the in-phase time-division-multiplexed signal and the quadrature-phase time-division-multiplexed signal as a time-division-multiplexed data signal;

    control means having a programmable non-volatile memory, said control means operatively coupled to said time-division-multiplexed channel decoder and to said time-division-multiplexed channel demodulator, responsive to the time-division-multiplexed data signal, for time-demultiplexing the time-division-multiplexed data signal into at least one of a control signal, paging signals and message signals, the control signal including at least one broadcast channel look-up table comprising the name, frequency and data rate of each of a plurality of broadcast channels available to the integrated communications terminal through the radio satellite unit, said control means operatively coupled to said transmitter and to said RF electronics and responsive to the control signal, said control means for outputting the message signals to said message display, said control means, responsive to a data signal from the input device, for generating a formatted data signal, said control means for initializing said integrated communications terminal with initial frequencies and data rates for receiving signals according to an initialization sequence, and said control means for generating the selectable data rate and frequency command signal, the time-division-multiplexed data rate and frequency command signal, and the transmitter frequency command signal;

    an audio decompressor and D/A converter, operatively coupled to said selectable channel decoder, for outputting analog signals;

    a data coder and modulator, operatively coupled to said control means, said data coder and modulator, responsive to the formatted data signal generated by said control means in response to the data signal from said input device, for convolutionally encoding the formatted data signal and for modulating, using quadrature-phase-shift-keying, the carrier signal with the formatted data signal as a data-modulated signal; and

    wherein said control means generates a Doppler-correction signal to modify the transmitter frequency command signal to adjust the frequency of the carrier signal transmitted by the transmitter.

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