Automatic frequency control circuit

Details Automatic frequency control circuit Automatic frequency control circuit

1992-02-27

1994-02-22

Chin, Stephen

Pulse or digital communications

Repeaters

Testing

455256, 455265, H04L 2706

Patent

active

052895068

ABSTRACT:
An AFC circuit stabilizes the frequency of an intermediate frequency signal to be applied to a demodulation circuit. A frequency conversion circuit responds to a local oscillation signal generated from a voltage-controlled oscillation circuit to convert the frequency of a digital modulation signal and applies the converted frequency to the demodulation circuit. A carrier reproduction circuit in the demodulation circuit reproduces the carrier of the intermediate frequency signal to output a synchronizing detection signal. The frequency of the reproduced carrier is frequency-divided by a frequency dividing circuit. A frequency division output thereof is counted by a counter for a definite period. Data is outputted from a microprocessor in response to a count output of the counter and the synchronizing detection signal, and the data is then converted into an AFC voltage by a D/A converter. The converted voltage is supplied as a control voltage to the voltage-controlled oscillation circuit. A stable intermediate frequency signal can be obtained by frequency-dividing the frequency of the carrier and counting the frequency division output thereof.

REFERENCES:
patent: 4641325 (1987-02-01), Hughes
patent: 4679246 (1987-07-01), Jeng
patent: 4696056 (1987-09-01), Morita
patent: 4727591 (1988-02-01), Manlove
patent: 4827488 (1989-05-01), Shibano
patent: 4879728 (1989-11-01), Tarallo
patent: 4947409 (1990-08-01), Raith et al.
patent: 5107522 (1992-04-01), Kitayama

Affiliated with

Also associated with

Rating

Automatic frequency control circuit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Automatic frequency control circuit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic frequency control circuit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-177706