Oscillator spurious sideband spectrum measuring device - with oscillator signal being transposed to different frequency and applied to Y-input of display device

摘要

The oscillator is an h.f. oscillator above 1 MHz. The examined oscillation is converted by a mixer using a variable frequency oscillator into a frequency of a narrow band-pass filter, through which it passes with its spurious sideband spectrum. The band-pass filter output signal is again mixed and filtered, and applied to the Y input of a display device, to whose X input a signal containing the frequency information is applied. The frequency information signal is derived from the i.f. output of the mixer (M) by a frequency evaluation device (FE) with a counter (Z).