FM Demodulator for a plurality of carrier frequencies
AssigneeVictor Company of Japan, Ltd.
InventorKazuyuki Suenaga
Life of this patent
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Abstract
An FM signal demodulating circuit comprises a peak differential type amplifier having two input terminals, a resonance circuit network connected between the two input terminals of the peak differential type amplifier, and a capacitor between the resonance circuit network and the ground. The resonance circuit network comprises a plurality of parallel resonance circuits which are connected in series and have respectively different parallel resonance frequencies. The demodulating circuit has a demodulating characteristic curve for demodulating FM signals having different carrier frequencies.
Claims4
An FM signal demodulating circuit for demodulating any one of a plurality of input signals having given different carrier frequencies, comprising:
- (a) a differential amplifier having two input terminals;
- (b) means for coupling of said FM signals to one of said input terminals of said differential amplifier;
- (c) a resonant circuit network connected between said two input terminals, of said differential amplifier, said resonant circuit network comprising a plurality of parallel resonant circuits which are connected in series, said parallel resonant circuits having different parallel resonance frequencies;
- and
- (d) a capacitor connected between the other input terminal of said differential amplifier and a reference potential, said plurality of parallel resonant circuits and said capacitor forming a series resonant circuit, said series resonant circuit having a plurality of series resonance frequencies, said series and parallel resonance frequencies having values selected to result in each of said FM signals having given carrier frequencies lying substantially in the middle between that one of said series resonance frequencies which is nearest to its respective carrier frequency and that one of said parallel resonance frequencies which is nearest to its respective carrier frequency.
Dependencies are inferred from the claim text.