The Nippon 2 channel FM wireless microphone system uses VHF 88 ? 106MHz to avert interfering frequencies and uses quartz crystal oscillating circuits to provide a steady frequency. The specially designed compounding circuit strongly improves S/N ratio and the multi-level quiet control circuit uses mute system to avoid signal interference on activation and shut down. This microphone system has an impedance of 600 Ohms, a dynamic range of >80dB, a distortion rate of <1%, and a frequency response of 80Hz ? 17KHz ? 3dB.