摘要:
Resonance frequencies f2, f3 detected in a resonance space are decided to be dip center frequencies. According to the measurement values obtained in a loudspeaker and a microphone in the resonance space, a basic amplitude frequency characteristic Ca and a target amplitude frequency characteristic Cd are obtained. The target amplitude frequency characteristic Cd has a greater smoothness than the basic amplitude frequency characteristic Ca on the frequency axis. The dip attenuation level and sharpness are decided according to the difference between the basic amplitude frequency characteristic Ca and the target amplitude frequency characteristic Cd at the dip center frequencies f2, f3 and in the vicinity thereof.
摘要:
An impulse response measurement with high precision is made possible with a simple device or signal processing, even if sampling clocks on the transmitting side and the receiving side are asynchronous at the time of measuring an impulse response of a measured system. An impulse response measuring method includes an input signal generating step of generating an input signal of an arbitrary waveform to be input to a measured system by using a synchronization signal having a first sampling clock frequency, a signal converting step of performing conversion on a measured signal output from the measured system into a discrete value system by using a synchronization signal having a second sampling clock frequency, and an inverse filter correcting step of correcting at least a phase of an inverse filter which is an inverse function of a function showing a frequency characteristic of the input signal according to a frequency ratio of the first sampling clock frequency and the second sampling clock frequency. Then, the impulse response of the measured system is measured using the inverse filter after correction.
摘要:
Resonant frequencies f2 and f3 detected in a resonant space are determined as center frequencies of a dip. Based on measurement values at a speaker and a microphone in the resonant space, a basic amplitude frequency characteristic Ca and a target amplitude frequency characteristic Cd are found. A smoothness degree on a frequency axis is larger in the target amplitude frequency characteristic Cd than the basic amplitude frequency characteristic Ca. A damping level and quality factor of the dip are determined based on a difference between the basic amplitude frequency characteristic Ca and the target amplitude frequency characteristic Cd in the center frequencies f2 and f3 of the dip and frequencies near the center frequencies.