Demodulators – Amplitude modulation demodulator – Having specific distortion – noise or other interference...
Patent
1984-10-01
1986-12-09
LaRoche, Eugene R.
Demodulators
Amplitude modulation demodulator
Having specific distortion, noise or other interference...
329137, H03D 302
Patent
active
046282726
ABSTRACT:
An inductorless quadrature demodulator for frequency modulated signals is disclosed. A limited FM signal is passed through an active filter (26) and a phase shift network (30) to produce a quadrature signal. The limited FM signal is compared with the quadrature signal in an EXCLUSIVE OR gate (24) and then low pass filtered (36) to obtain recovered audio. The active filter (26) includes a transconductance amplifier (60) whose center frequency can be adjusted by appropriate adjustment of the amplifier's bias current. The bias current is temperature compensated to allow operation of the demodulator over a wide temperature range.
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Davis Walter L.
Prieto Yolanda
Downey Joseph T.
LaRoche Eugene R.
Mis D. C.
Motorola Inc.
Roney Edward M.
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