Muting circuit

Claim 2

In an angle modulation receiver adapted for providing information angle modulated on a carrier wave, said carrier wave being characterized by a reduction in amplitude in the presence of noise, the combination comprising: an angle modulation detector including frequency responsive means for supplying an angle modulated carrier wave; means coupled to said frequency responsive means for detecting the envelope of said angle modulated carrier wave; means direct current coupled to said detecting means for inverting said detected envelope; biasing means coupled at least to said inverting means for biasing said inverting means in the vicinity of a conduction threshold; and rectifying means direct current coupled to said inverting means, for providing a DC voltage representative of troughs in said angle modulated carrier wave suitable for reducing the gain of an associated output amplifier.

Claim 3

In an angle modulation receiver adapted for providing information angle modulated on a carrier wave, said carrier wave being characterized by a reduction in amplitude in the presence of noise, the combination comprising: an angle modulation detector including frequency responsive means for supplying an angle modulated carrier wave; means coupled to said frequency responsive means for detecting the envelope of said angle modulated carrier wave; means direct current coupled to said detecting means for inverting said detected envelope; biasing means coupled at least to said inverting means for biasing said inverting means in the vicinity of a conduction threshold; and rectifying means direct current coupled to said inverting means, for providing a DC voltage representative of troughs in said angle modulated carrier wave suitable for reducing the gain of an associated output amplifier.

Claim 4

In an angle modulation receiver adapted for providing information angle modulated on a carrier wave, said carrier wave being characterized by a reduction in amplitude in the presence of noise, the combination comprising: an angle modulation detector including frequency responsive means for supplying an angle modulated carrier wave; means coupled to said frequency responsive means for detecting the envelope of said angle modulated carrier wave; means direct current coupled to said detecting means for inverting said detected envelope; biasing means coupled at least to said inverting means for biasing said inverting means in the vicinity of a conduction threshold; and rectifying means direct current coupled to said inverting means, for providing a DC voltage representative of troughs in said angle modulated carrier wave suitable for reducing the gain of an associated output amplifier.

Claim 5

In apparatus adapted for processing information angle modulated on a carrier wave, said carrier wave being characterized by a reduction in amplitude in the presence of noise, a muting circuit comprising: means for detecting the envelope of said angle modulated carrier wave, said means comprising a first transistor having emitter, base and collector electrodes, said collector electrode being coupled to a source of said carrier wave, a first capacitor coupled between said collector and base electrodes of said first transistor, and a second capacitor coupled from the emitter electrode of said transistor to a reference terminal for filtering out said carrier wave; means for inverting said detected envelope; and rectifying means coupled to said inverting means for providing a DC voltage representative of troughs in said angle modulated carrier wave suitable for reducing the gain of an associated output amplifier.

Claim 6

In apparatus adapted for processing information angle modulated on a carrier wave, said carrier wave being characterized by a reduction in amplitude in the presence of noise, a muting circuit comprising: means for detecting the envelope of said angle modulated carrier wave, said means comprising a first transistor having emitter, base and collector electrodes, said collector electrode being coupled to a source of said carrier wave, a first capacitor coupled between said collector and base electrodes of said first transistor, and a second capacitor coupled from the emitter electrode of said transistor to a reference terminal for filtering out said carrier wave; means for inverting said detected envelope; and rectifying means coupled to said inverting means for providing a DC voltage representative of troughs in said angle modulated carrier wave suitable for reducing the gain of an associated output amplifier.

Claim 7

A muting circuit according to claim 2 wherein said means for inverting said detected envelope and said rectifying means comprises: a. a second transistor having emitter, base, and collector electrodes, the base electrode of said second transistor beiNg coupled to the emitter electrode of said first transistor, the emitter electrode of said second transistor being coupled to said reference terminal; b. means for coupling the collector electrode of said second transistor to a terminal adapted for connection to an operating potential supply; c. a third transistor having emitter, base, and collector electrodes, said base electrode being coupled to the collector electrode of said second transistor; d. means for coupling the collector electrode of said third transistor to said terminal adapted for connection to an operating potential supply; and e. means for coupling the emitter electrode of said third transistor to a network for providing a DC voltage representative of the troughs in said input carrier wave envelope.

Claim 8

A muting circuit according to claim 3 wherein all of said components except said network are fabricated on a monolithic integrated circuit chip.

Claim 9

A muting circuit according to claim 3 wherein said network for providing a DC voltage includes a resistor and a capacitor, said capacitor being charged to a voltage porportional to the number of holes in said angle modulated carrier wave envelope.

Claim 10

A muting circuit for frequency modulation receivers comprising: a. means for detecting the envelope of frequency modulated input signal waves including a first transistor having emitter, base, and collector electrodes; b. means, coupled to said detecting means, for inverting the envelope of said input signal waves including a second transistor having emitter, base, and collector electrodes, the base electrode of said second transistor being coupled to the emitter electrode of said first transistor and the emitter electrode of said second transistor being coupled to a first terminal; c. means for coupling the collector electrode of said second transistor to an operating potential supply terminal; d. means, coupled to said inverting means, for rectifying said input signal wave envelope including a third transistor having emitter, base, and collector electrodes, the base electrode of said third transistor being coupled to the collector electrode of said second transistor, the collector electrode of said third transistor being coupled to an operating potential supply terminal; and e. means for coupling the emitter electrode of said third transistor to a network for providing a DC voltage representative of the troughs in said input signal envelope.

Claim 11

A muting circuit for frequency modulation receivers comprising: a. means for detecting the envelope of frequency modulated input signal waves including a first transistor having emitter, base, and collector electrodes; b. means, coupled to said detecting means, for inverting the envelope of said input signal waves including a second transistor having emitter, base, and collector electrodes, the base electrode of said second transistor being coupled to the emitter electrode of said first transistor and the emitter electrode of said second transistor being coupled to a first terminal; c. means for coupling the collector electrode of said second transistor to an operating potential supply terminal; d. means, coupled to said inverting means, for rectifying said input signal wave envelope including a third transistor having emitter, base, and collector electrodes, the base electrode of said third transistor being coupled to the collector electrode of said second transistor, the collector electrode of said third transistor being coupled to an operating potential supply terminal; and e. means for coupling the emitter electrode of said third transistor to a network for providing a DC voltage representative of the troughs in said input signal envelope.

Claim 12

A muting circuit for frequency modulation receivers according to claim 6 wherein said means for detecting the envelope of frequency modulated input signal waves further includes a first capacitor coupled between the collector and base electrodes of said first transistor and a second capacitor, coupled from the emitter electrode of said first transistor to a reference terminal, for filtering out the carrier wave frequency of said frequency modulated input signal waves.

Claim 13

A muting circuit according to claim 7 wherein said second transistor is biased into conduction by a voltage appearing across said second capacitor being the result of input signal waves and stops conduction when the voltage appearing across said second capacitor decreases below the threshold of conduction of said second transistor being a result of holes in said signal waves.