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A method and apparatus related to a communication system in which a plurality of remote units encode data bursts using a predetermined codeword set and transmit the encoded data bursts to a hub station over a multiple-access channel. When the hub station receives a data burst from one of the remote

A method and apparatus related to a communication system in which a plurality of remote units encode data bursts using a predetermined codeword set and transmit the encoded data bursts to a hub station over a multiple-access channel. When the hub station receives a data burst from one of the remote units, the hub station demodulates the received data burst and correlates the received data burst with each codeword within the predetermined codeword set to determine which codeword has the maximum correlation. The hub station uses the correlation to derive a timing synchronization signal and/or a carrier frequency adjustment signal to be sent back to the remote unit. The signals provide information to the remote unit to synchronize its timing or adjust its carrier frequency for transmitting subsequent data bursts. The hub station may also use the correlation to estimate a signal-to-noise ratio.

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A method and apparatus related to a communication system in which a plurality of remote units encode data bursts using a predetermined codeword set and transmit the encoded data bursts to a hub station over a multiple-access channel. When the hub station receives a data burst from one of the remote

A method and apparatus related to a communication system in which a plurality of remote units encode data bursts using a predetermined codeword set and transmit the encoded data bursts to a hub station over a multiple-access channel. When the hub station receives a data burst from one of the remote units, the hub station demodulates the received data burst and correlates the received data burst with each codeword within the predetermined codeword set to determine which codeword has the maximum correlation. The hub station uses the correlation to derive a timing synchronization signal and/or a carrier frequency adjustment signal to be sent back to the remote unit. The signals provide information to the remote unit to synchronize its timing or adjust its carrier frequency for transmitting subsequent data bursts. The hub station may also use the correlation to estimate a signal-to-noise ratio. acteristic filter function of the IF amplifier and filter, the input of the compensating filter arranged to receive the modulation signal and apply the complement signal thereto, thereby removing the transmit modulation from the received demodulated audio signal. 2. The apparatus of claim 1 wherein said reference circuit is a phase lock loop.3. The apparatus of claim 1 further comprising an amplitude compensator associated with the compensating filter and having an amplitude attenuation characteristic applied to the subtractor circuit which is the same as distortion in the detector circuit.4. The apparatus of claim 1 wherein said receive side has an input connected to an RF amplifier and filter with the output thereof being said RF input signal.5. The apparatus of claim 1 wherein said filter function is a linear combination of the characteristic filter function of the RF output signal and the characteristic filter function of the IF amplifier and filter.6. A transceiver for transmitting and receiving radio frequency (RF) signals, comprising: an antenna for transmitting a first modulated RF signal and receiving a second modulated RF signal, a transmitter circuit coupled to the antenna and generating the first RF signal, the transmitter circuit including a modulator for modulating a first RF signal with a transmit audio signal, the transmitter circuit including a phase locked voltage controlled oscillator (VCO) with a characteristic filter passband associated with the VCO output signal sent to the antenna, a receiver circuit coupled to the antenna and receiving the second RF signal, the receiver circuit having a down-converting mixer, and an IF amplifier and filter with an input being the VCO output signal, an output of the mixer having a first frequency response and a demodulator circuit for converting the first frequency response to a baseband signal, the demodulator circuit connected to a subtractor circuit, and a compensating filter circuit coupled between the VCO of the transmitter circuit and the subtractor circuit of the receiver circuit and having a second frequency response that is the same as the first frequency response, wherein the first frequency response signal is combined with the second frequency response signal, thereby accurately removing the transmit modulation from the baseband signal of the receiver circuit. 7. The transceiver of claim 6 wherein the transmitter circuit includes a phase lock loop (PLL) synthesizer coupled to the VCO, the PLL synthesizer having a third frequency response.8. The transceiver of claim 6 wherein the compensating filter circuit comprises at least one highpass filter.9. The transceiver of claim 1 wherein the compensating filter circuit comprises at least one each of highpass and lowpass filters.10. The transceiver of claim 6 wherein the compensating filter comprises at least one highpass filter connected in series with at least one lowpass filter.11. The transceiver of claim 6 wherein the VCO of the transmitter circuit is directly modulated with a baseband audio signal.12. The apparatus of claim 6 further comprising an amplitude compensator associated with the compensating filter and having an amplitude attenuation characteristic applied to the subtractor circuit which is the same as the amplitude distortion in the demodulated audio signal.