| 摘要 |
PURPOSE:To perform stable measurement without the effect of noise, by comparing the amplitude of the output signal of a transmitting part with a reference value, suppressing the detected value to the reference value, thereby keeping the amplitude of the output signal of the transmitting part at a constant value. CONSTITUTION:The output signal of a driver part 17 is received, and envelop detection of the output signal is performed by an envelop detecting part 18 so as to detect the amplitude value. The output signal of the envelop detecting part 18 is compared with a reference voltage (a). The output, which is suppressed to the reference voltage, is supplied to the gain control terminal of an amplifier part 16 through a Miller integrating circuit 19. Namely, the amplitude of the output signal of the driver part 17 is always kept at a constant value by the amplitude stabilizing circuit. |
