Patent ID: 6671503
Filing Date: 2003-12-30
Classification: H03G

Abstract:
A wireless microphone system having a wireless microphone for transmitting therefrom electric wave containing audio, tone and noise signals; and a receiver unit, wherein said receiver unit includinga) a receiver device having an antenna through which the electric wave is received, the electric wave being demodulated therein to be outputted therefrom; b) a detector circuit connected with said receiver device so as to detect a signal level of said demodulated electric wave to be outputted therefrom; c) an audio signal detection circuit connected with said detector circuit through a filter so as to detect said audio signal from the demodulated electric wave; d) a tone signal detection circuit connected with said detector circuit through a filter so as to detect said tone signal from the demodulated electric wave; e) a noise signal detection circuit connected with said detector circuit through a filter so as to detect said noise signal from the demodulated electric wave; f) a plurality of A/D converters each connected with said signal level detection circuit, tone signal detection circuit, and noise signal detection circuit so as to convert said signal level, tone signal, and noise signal from analog signals to digital signals, one of the digital signals being a parameter signal for determining received state of said electric wave; g) a mute circuit connected with said audio signal detection circuit so as to turn down volume of said audio signal in accordance with said parameter signal; h) an input device for inputting threshold that is set in accordance with said parameter signal from said electric wave in normal state; and, i) a controller for switching on or off said mute circuit by the method of detecting a first period of time which is previously set in accordance with said input threshold, detecting a second period of time during which period the said electric wave to be received reaches said input threshold, and outputting a mute-controlling signal at Hi or Lo to said mute circuit in accordance with difference between said first period of time and said second period of time.