发明授权
US4217552A Receiver 失效
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Receiver
摘要:
A digital tuning receiver having an electrically tuneable tuner and an AFT circuit is driven in a unidirectional sweep by the D/A converted output of a reversible counter. The reversible counter continues to count input pulses, and the unidirectional sweep continues until stopped by the reception of a signal which produces a first signal from an AFT frequency discriminator followed within a predetermined time by a second signal of opposite polarity from the AFT frequency discriminator. The number stored in the stopped reversible counter may be further adjusted by AFT signals and stored for later recall. If the second signal is not received within a predetermined time, as occurs with spurious beat signals, the sweep is not stopped but continues until a proper signal is received.
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