| 摘要 |
PURPOSE:To obtain a sampling signal having an optional and desired fractional number by using the output from a voltage control type crystal oscillator as a sampling signal and setting a frequency at an optional prescribed value by a fractional N oscillator. CONSTITUTION:The alternating signal past a filter 11 from the crystal oscillator 30 is introduced into the element 12 to be measured and the output signal from and input signal to the element 12 are impressed to samplers 13, 15. The output from the oscillator 30 is introduced to the fractional N oscillator 20, from which the output is impressed to a phase detector 21. A closed loop is constituted of the detector 21 as well as a filter 22 and the voltage control type crystal oscillator 23. The output from the oscillator 23 is used as a sampling signal. The period of the signal impressed to the element 12, designated as T and the period of the sampling signal, designated as (t), are provided with the relation t=nT+T/m (m, n are positive integer, m is the number of samples). The set frequency of the sampling signal is set by the oscillator 20 by changing the fractional number m.
|
