AUTOMATIC DIGITAL FINE TUNING SYSTEM

    公开(公告)号:CA1213384A

    公开(公告)日:1986-10-28

    申请号:CA492645

    申请日:1985-10-09

    Applicant: RCA CORP

    Inventor: WINE CHARLES M

    Abstract: In automatic fine tuning (AFT) apparatus in a superheterodyne receiver, the IF carrier is selectively filtered and is applied to a signal multiplier arrangement. An auxiliary heterodyning signal is also applied to the multiplier arrangement, so as to produce an offset signal having a frequency proportional to the frequency difference between the IF carrier and the heterodyning signal. The offset signal is applied to a microprocessor programmed to produce a control signal for controlling the local oscillator to reduce frequency deviation between the IF signal and a nominal IF frequency.

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