The sampling
oscilloscope of the present invention includes a trigger generation circuit and a
control unit, the trigger generation circuit generates a gate
signal for sampling an input pattern
signal, and has: a direct digital
frequency synthesizer with a phase accumulator to output A frequency output trigger
clock input according to the count value of the phase accumulator; a bandpass filter, which limits the
passband of the trigger
clock output by the direct digital
frequency synthesizer; and a variable
frequency divider, which passes through the bandpass A filter restricts a
passband of a trigger
clock for frequency division, the
control unit controls the direct digital
frequency synthesizer and the trigger generating circuit, and the sampling
oscilloscope is characterized in that the
control unit uses the The pattern period of the strobe
signal is used as a reference to calculate the
phase offset of the strobe period of the strobe signal, and to eliminate the calculated
phase offset, change the direct digital frequency synthesizer. The count value of the phase accumulator, from which the phase is adjusted.