關鍵詞： 聲校準器、負反饋、聲壓級
ABSTRACT
With the enhanced awareness of environmental protection, noise research has become an increasingly important position in people's living. Then people began to produce a sound level meter, an instrument which is used to measure noise level. This subject is to study an instrument called the sound level calibrator that can generate one or more constant pressure of the sound source in one frequency point or a few. It is used to calibrate the absolute acoustic sound pressure sensitivity of the test microphone, sound level meter and other measuring instruments, and sometimes it is also be a part of the sound measuring devices.
This paper introduces the working principle and the main performance characteristics of the sound level calibrator with negative feedback. It has added the feedback and adjustment of the output based on the original sound level calibrator which can only output a single sound signal. The sound level calibrator with negative feedback in this paper not only can generate 94 dB sound pressure, but also can produce several sound pressure level of 114 dB (or 104 dB). Since the MCU can adjust the feedback sound signal, the stability of the sound signal of the sound level calibrator with negative feedback is better than others.
