Abstract: A digital signal processing apparatus has: an A/D converter for A/D converting an input signal to be processed to a digital signal, an analog comparator for comparing the input signal with a predetermined threshold voltage and generating a comparison signal as a binary signal, a first input device for inputting at least binary data of a reference wave to be triggered, a discriminator for discriminating a coincidence between the binary signal from the analog comparator and the binary data entered at the first input device and generating a coincidence signal, a fetching section, triggered in response to the coincidence signal from the discriminator, for fetching the digital signal from the A/D converter, and a processor for performing predetermined processing of the digital signal fetched by the fetching device.

Abstract: In a digital wave observation apparatus having an A/D converter for A/D converting an input signal, a trigger level setting device for setting a trigger level, a trigger signal generator for comparing the input signal with a set trigger level and generating a trigger signal, a wave memory for storing an A/D converted input signal in response to the trigger signal, and a display for displaying the input signal stored in the wave memory, the apparatus has a trigger level display device for displaying a horizontal line corresponding to a trigger level on the display irrespective of generation of the trigger signal.