Patent ID: 6219108
Filing Date: 2001-04-17
Classification: H03J,H04N

Abstract:
A radio receiver for selectively receiving one of a plurality of television signals in respective allocated transmission channels each of a prescribed bandwidth, some of which television signals are digital television signals, said radio receiver comprising:a first detector which generates a first detector response to any television signal in one of said allocated transmission channels selected to be received, said first detector being of a type that translates the frequencies of the selected transmission channel to a range of intermediate frequencies of said prescribed bandwidth, which range of intermediate frequencies is above baseband and is substantially the same whether or not said any television signal in said selected transmission channel is a digital television signal;first and second intermediate-frequency amplifier chains, each receptive of said first detector response as an input signal, said first intermediate-frequency amplifier chain supplying an amplified first final intermediate-frequency signal, and said second intermediate-frequency amplifier chain supplying an amplified second final intermediate-frequency signal, each of said first and second intermediate-frequency amplifier chains having a respective initial portion which has its gain controlled and having a respective final portion which also has its gain controlled, said initial portions of said first and second intermediate-frequency amplifier chains each having an input port connected for receiving said first detector response and having a respective output port, said final portion of said first intermediate-frequency amplifier chain having an output port connected to said symbol decoder and having an input port, said final portion of said second intermediate-frequency amplifier chain having an output port connected to said video detector and having an input port;a local oscillator for supplying local oscillations at a frequency offset from the frequencies within the frequency range of said first detector response;a first mixer having a first input port to which the output port of said initial portion of said first intermediate-frequency amplifier chain is connected, having a second input port connected for receiving said local oscillations from said local oscillator; and having an output port connected for supplying a first mixer output signal to the input port of said final portion of said first intermediate-frequency amplifier chain;a second mixer having a first input port to which the output port of said initial portion of said second intermediate-frequency amplifier chain is connected, having a second input port connected for receiving said local oscillations from said local oscillator; and having an output port connected for supplying a second mixer output signal to the input port of said final portion of said second intermediate-frequency amplifier chain;synchrodyning circuitry for generating a baseband signal responsive to said amplified first final intermediate-frequency signal;a symbol decoder responsive to said baseband signal for supplying data in serial-bit form when said selected one of said television signals is a digital television signal; anda video detector responsive to said amplified second final intermediate-frequency signal for supplying a composite video signal when said selected one of said television signals is an analog television signal.