Monitoring system for voltage tunable receivers and converters utilizing an analog function generator
First Claim
1. Apparatus for determining the channel of a plurality of channels to which a voltage tunable receiver is tuned comprisingmeans for generating a counting sequence, each count of said counting sequence being representative of one of said plurality of channels,means responsive to said counting sequence for providing a first signal having an amplitude linearly related to said counting sequence,means responsive to the amplitude of said first signal for providing a second signal having an amplitude nonlinearly related to said counting sequence andmeans responsive to said second signal and the tuning voltage of said receiver for suspending the counting sequence when the amplitude of said second signal has a predetermined relationship to the amplitude of said tuning voltage.
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Abstract
A system for monitoring the channel to which a remotely located voltage tunable receiver or converter is tuned includes a comparator for comparing the magnitude of the tuning voltage with an internally generated reference voltage to determine the channel number. The reference voltage is generated by a counter driving a linear digital-to-analog converter. The output of the digital-to-analog converter is modified with an analog function generator to provide a piecewise linear approximation of the receiver tuning voltage versus channel number characteristic. A window comparator is utilized to compare the output of the function generator with the tuning voltage and to stop the counter and transfer the contents of the counter to an output circuit when the magnitude of the reference voltage approaches that of the tuning voltage. The contents of the counter at the time the counter is interrupted is indicative of the channel number of the station being received.
163 Citations
13 Claims
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1. Apparatus for determining the channel of a plurality of channels to which a voltage tunable receiver is tuned comprising
means for generating a counting sequence, each count of said counting sequence being representative of one of said plurality of channels, means responsive to said counting sequence for providing a first signal having an amplitude linearly related to said counting sequence, means responsive to the amplitude of said first signal for providing a second signal having an amplitude nonlinearly related to said counting sequence and means responsive to said second signal and the tuning voltage of said receiver for suspending the counting sequence when the amplitude of said second signal has a predetermined relationship to the amplitude of said tuning voltage.
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10. A method for determining the channel of a plurality of channels to which a voltage tunable receiver is tuned comprising the steps of
generating a first variable signal having a characteristic linearly related to the sequence of channels to which the receiver may be tuned, modifying said first signal to provide a second variable signal having a predetermined characteristic that is nonlinearly related to said sequence of channels, comparing said predetermined characteristic of said second signal with said tuning voltage and determining the channel corresponding to said second signal when the predetermined characteristic of said second signal has a predetermined relationship to said tuning voltage.
Specification