Audio-Technica U.s., Inc.

Steve Hebrock

Kenneth R Reichel

A system for monitoring the level of an intelligence-containing audio frequency signal wherein an operator audibly monitors the signal but cannot adequately monitor a visual level indicator. The system utilizes a threshold detector which compares the level of an audio frequency signal to a preselected level and generates a control signal if the audio frequency signal exceeds the threshold. The system further includes a gate which couples a tone to the headphones of the operator in response to generation of the control signal. In an alternative embodiment, if a second threshold is exceeded, the threshold detector generates a second control signal which changes the tone signal frequency.

Audible audio level indicator

A full duplex microphone communications system permitting simultaneous bi-directional communications for a two conductor shielded microphone cable. A talkback signal is injected by an encoder at one end using a balanced input to transmit a common-mode signal on the two conductors of the microphone cable using the shield as a ground reference. This signal is then decoded at the other end of the cable by decoding circuitry which covers the common-mode talkback signal.

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Akron, OH, United States of America

Steve Hebrock