Sampling oscilloscope, trigger generation method, and sampling method

Abstract

A sampling oscilloscope includes a trigger generation circuit that includes a direct digital synthesizer (DDS) that outputs a trigger clock input in an operable frequency range at an arbitrary output frequency, a band pass filter (BPF) that limits a pass band of the trigger clock output from the direct digital synthesizer and a variable frequency divider that divides a frequency of the trigger clock of which the pass band is limited by the band pass filter, and generates a strobe signal of a frequency at which a sampler can be operated. The sampling oscilloscope includes a controller that calculates a phase shift amount with reference to a pattern cycle of data generated by a one-time strobe signal and adjusts a phase by changing a count value of a phase accumulator of the direct digital synthesizer so that the calculated phase shift amount is eliminated.