| 摘要 |
PROBLEM TO BE SOLVED: To obtain a waveform measuring apparatus whose resolution is high and whose band is wide by a method wherein a signal at a prescribed frequency in a modulator output decided by a reference signal is extracted so as to be amplified by a lock-in amplifier. SOLUTION: A trigger signal fTR which is input to a down counter 1704 is converted into a signalΔf2 at a frequency whose repetitive frequency is lower than that of the trigger signal fTR, it is input to a pulse generator 1705, and second sampling pulses are generated. By using the second sampling pulses, a sampler module 1701 samples a measuring signal which is passed through a low-pass filter. Then, a noise is removed by using a lock-in amplifier 1703, and only a signal to be measured is amplified. The measuring signal which is converted into a signalΔf3 by the sampler module 1701 is modulated by a modulator 1702 to be square waves which are synchronized with a reference signal generated by a reference-signal generator 1702, it is input to the lock-in amplifier 1703, and only the measuring signal which can be phase-detected by using the reference signal can be taken out.
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