Automatic frequency control which monitors the frequency of a vo

Details Automatic frequency control which monitors the frequency of a vo Automatic frequency control which monitors the frequency of a vo

1994-03-29

1997-02-11

Eisenzopf, Reinhard J.

Telecommunications

Receiver or analog modulated signal frequency converter

Signal selection based on frequency

4551822, 4551971, 455260, 455264, H04B 116

Patent

active

056031092

ABSTRACT:
An automatic frequency control circuit measures the deviation in frequency of a selected signal from a reference frequency and when the deviation exceeds a selected threshold which is variable, steps the frequency of the selected signal back to the proper frequency. The selected signal is typically an intermediate frequency (IF) signal in a radio receiver. For detection of frequency deviation, an exclusive OR (EX-OR) circuit receives a reference signal having a frequency proportional to a desired IF carrier frequency and an input signal having a frequency proportional to an actual IF frequency. A divider coupled to a voltage controlled oscillator (VCO) used in demodulation of the IF signal provides the input signal. An output signal of the EX-OR circuit includes a component with a frequency proportional to the difference between the actual and desired IF frequencies. A low pass filter isolates that component, and a charge pump generates a control voltage proportional to the frequency of that component. A comparison of the control voltage and the threshold determines whether the actual IF frequency should be changed.

REFERENCES:
patent: 4367558 (1983-01-01), Gercekci et al.
patent: 4479256 (1984-10-01), Sewerinson
patent: 5263195 (1993-11-01), Panther et al.
patent: 5390348 (1995-02-01), Magin et al.
patent: 5416805 (1995-05-01), Tonello et al.

Affiliated with

Also associated with

Rating

Automatic frequency control which monitors the frequency of a vo 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 which monitors the frequency of a vo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic frequency control which monitors the frequency of a vo will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-351466