Phase-locked loop FM demodulator

Details Phase-locked loop FM demodulator Phase-locked loop FM demodulator

1991-03-11

1992-08-18

Mis, David

Demodulators

Frequency modulation demodulator

Input signal combined with local oscillator or carrier...

331 23, 331 25, H03D 300, H03L 7091

Patent

active

051402785

ABSTRACT:
A conventional phase-locked loop is improved by replacing its phase detector with one comprising a linear ramp generator and a sample-and-hold circuit, thus eliminating the need for a lowpass loop filter, although the output of the sample-and-hold circuit may be filtered in the case of a very low level modulating signal on the incoming FM signal, but then filtering is not a difficult problem as in a conventional phase-locked loop. The result is FM demodulation by zero-order estimation. For FM demodulation by first-order estimation, the arithmetic difference between adjacent samples is formed, and using a second sample-and-hold circuit an arithmetic difference signal is produced as an input to a second ramp generator that is reset after each sampling cycle to generate a ramp the slope of which is a function of the arithmetic difference signal stored in the second sample-and-hold circuit. The ramp thus generated by the second ramp generator is arithmetically summed with the zero-estimation signal from the first sample-and-hold circuit to form a first-order estimation signal. Filtering such a first-order estimation signal is less of a problem than filtering a zero-order estimation signal.

REFERENCES:
patent: 3142806 (1964-07-01), Fernandez
patent: 3567959 (1971-03-01), Kaneko et al.
patent: 3697781 (1972-10-01), McLean
patent: 3761829 (1973-09-01), Spaulding
patent: 3761874 (1973-09-01), Landrum, Jr.
patent: 3973212 (1976-08-01), Walloch
patent: 3979692 (1976-09-01), Benoist et al.
patent: 3980971 (1976-09-01), Sato
patent: 4004235 (1977-01-01), Roberts
patent: 4184122 (1980-01-01), Clark et al.
patent: 4344040 (1982-08-01), Reilly et al.
patent: 4550424 (1985-10-01), Cheng et al.
patent: 4564823 (1986-01-01), Stahler
patent: 4608540 (1986-08-01), Tsuchiya et al.
patent: 4628271 (1986-12-01), Takayama
patent: 4672447 (1987-01-01), Moring et al.
patent: 4682118 (1987-07-01), Thiel
patent: 4780887 (1988-10-01), Otani et al.
patent: 4864252 (1989-09-01), Heck
P. Horowitz and W. Hill, "The Art of Electronics", Cambridge University Press, Second Edition, 1989, pp. 644-645.

Affiliated with

Also associated with

Rating

Phase-locked loop FM demodulator does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Phase-locked loop FM demodulator, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Phase-locked loop FM demodulator will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1251469