| 摘要 |
A method and apparatus for determining the status of a battery that powers a wireless microphone transmitter. The transmitter has a tone oscillator that produces a tone of a frequency beyond the audible limit which is transmitted, along with acoustical signals, to a receiver. The amplitude of the tone is changed as the battery voltage of the transmitter decreases. The receiver for the transmitter includes a circuit that detects the changes in amplitude of the high frequency tone. The front panel of the receiver, for example, may contain an LCD display on which a battery fuel gauge is present, indicating the remaining battery life of transmitter. When an amplitude change beyond a threshold is detected, the fuel gauge is updated, and the respective bar on the gauge is turned off.
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