Audible audio level indicator

摘要

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.