RICHARD W MIDDLESTEAD
Engineers in El Toro, CA
License number
Pennsylvania PE010166E
Category
Engineers
Type
Professional Engineer
Address
Address
2
El Toro, CA 92630
Pennsylvania
Pennsylvania
Professional information
Frequency Shift Key Demodulator
US Patent:
3979685, Sep 7, 1976
Filed:
Sep 16, 1974
Appl. No.:
5/506209
Inventors:
David M. Motley - Santa Ana CA
King Y. Cheng - Tustin CA
Richard W. Middlestead - El Toro CA
King Y. Cheng - Tustin CA
Richard W. Middlestead - El Toro CA
Assignee:
Hycom Incorporated - Irvine CA
International Classification:
H03D 300, H04L 2714
US Classification:
329105
Abstract:
A demodulator for detecting first and second frequencies in an analog input signal includes a limiter providing first pulses having a short duration in response to the first frequency and having a long duration in response to the second frequency. A first counter provides a first reference signal including second pulses, and a second counter provides a second reference signal including third pulses. Logic means responsive to the second and third pulses provide a signal including fourth pulses during periods corresponding to the first frequency and a signal including fifth pulses during periods corresponding to the second frequency. An up-down counter is responsive to the fourth pulses to provide a first output signal and responsive to the fifth pulses to provide a second output signal. The fourth and fifth pulses have frequencies and durations providing the counter with substantially equal counting rates during the periods corresponding to the first and second frequencies of the analog signal.