| 摘要 |
PURPOSE: To obtain the phase characteristics of a filter by using an arbitrary waveform generator as a signal source, and computing the phase characteristics by FFT processing from the measured data, which have passed a filter part and bypassed the filter part. CONSTITUTION: A sweeping sine wave 71sin is generated in synchronization with the start of sampling in an AD converter 14. An arbitrary waveform generator 70, which supplies the signal to a filter part 80 as the signal source for measuring phase characteristics, is provided. The passing characteristic of each filter of the filter part 80 is sampled and quantized into the digital signal in synchronization with the passing sweeping sine wave 71sin. An AD converter 14, which stores the signal into a buffer memory 16, is provided. An FFT processing part 18, which receives the obtained data in the buffer memory 16 and converts the data of the function of a time (t) into complex-function-data lines R(f) and I(f) of a frequency (f), is provided. A phase operating part 20, which receives the complexfunction-data lines R(f) and I(f) from the FFT processing part 18 and computes a phaseϕ(f) at each frequency (f), is provided.
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