Abstract: An oscilloscope vertical amplifier with Boolean combinatorial trigger generator capability is disclosed. While the display output is fully analog, the trigger output to the time base is digital with a user selectable Boolean function of the analog input signals. Also included is nested triggering, edge as well as level sensitivity, and a trigger filter to selectively inhibit high frequency events. The delay times of the analog and digital signal paths are matched by means of analog delay lines before presentation by a visual display to present the analog and digital signals in time coincidence to the oscilloscope main frame.

Abstract: An improved signal input circuit suitable for use in wideband oscilloscopes includes a high impedance controllable attenuator stage.

Abstract: A restart circuit for a digital processor is disclosed. A regularly serviced processor signal is continuously monitored and if an intermittant soft failure of the processor occurs, causing the processor signal to go high or low or toggle in an irregular fashion, a restart pulse is automatically generated. Thus, with the occurrence of a soft failure, the operator no longer has to manually reset the processor system.