Multi-mode oscilloscope trigger with compensating trigger delay

In a sampling digital oscilloscope means operable to measure the time period from the occurrence of a trigger signal to the onset of signal sampling period so that commulatively stored samples of a repetitively sampled signal visually coincide, producing a clear, jitter-free signal image. Moreover, the trigger signal is also produced according to a hold-off mode to allow the user to evaluate the results of processing the sampled signals by the digital oscilloscope before adding new data samples. In addition, a triggered update of stored data by new signals is provided, which is further controllable via an arm/disarm control to interrupt realtime updating of signals, allowing the user to observe signal changes as they occur.