Fast analog chopper multiplexer for oscilloscope recording of single‐shot events

The design and construction of an electronic circuit to multiplex two analog signals for display by trace chopping on a fast single‐beam oscilloscope is presented. The circuit uses a Schottky ring diode modulator as a control switch and is unique in having a chopping frequency of up to 400 MHz with switching times between channels of less than 0.7 ns. Used with an oscilloscope with sufficient bandwidth, it is then possible to obtain pseudosimultaneous display of fast single‐shot events. In conjunction with a Tektronix 7834 oscilloscope with a 7A19 plug in, the maximum signal bandwidth of the prototype is measured to be 150 MHz, and the interchannel rejection ratio greater than 24 dB at a chopping frequency of 200 MHz.