パーソナルコンピュータを利用した信号圧縮法によるパイプ内音場の測定

抄録

A microprocessor based measuring system of an impulse and or frequency response by a signal compression method has been developed. The signal compression method uses special computer generated test signal can improve S/N ratio immensely. This method can be applied most effectively to analyse wave propagation system though it can be used for any liner system. A portable signal processing system has been constructed using 8 bits personal computer. Machine language programs for FFT and other computations were developed. This system was applied to analyse multiple reflections of sound wave in circular cross-section duct. Sound pressures were measured by an inserted 1/4 inch condenser microphone and each reflected wave could be separated and analysed. Particle velocity in the duct was computed from two neighboring measurements of sound pressure. Then sound energy flow was computed from product of sound pressure and velocity. Newly developed microprocessor based system is useful for field measurements of wave propagation phenomena.