| 摘要 |
<p>A digital tuning receiver having an electric tuning tuner with at least one signal-controlled variable reactance element which converts an input radio frequency signal to an intermediate frequency signal, a demodulating circuit connected to the tuner for reproducing a desired signal, a frequency discriminating circuit connected to the tuner for generating an up-signal when a received frequency is lower than the center frequency and a down-signal when the received frequency is higher than the center frequency, a pulse generator for producing counting pulses, a counter for counting the counting pulses from the pulse generator, a tuning frequency control circuit connected to the tuner for controlling the tuning frequency of the tuner in response to the condition of the counter, a first flip-flop circuit for controlling the supply of counting pulses to the counter, and an up-sweep starting device or down-sweep starting device for setting the first flip-flop circuit. In this case, the receiver further has a second flip-flop circuit which is set when a set output from the first flip-flop circuit and the up-signal or down-signal from the frequency discriminating circuit exist at the same time, and a resetting circuit for resetting the first flip-flop circuit when a set output from the second flip-flop circuit and the down-signal or up-signal from the frequency discriminating circuit exist at the same time.</p> |
