Abstract: An oscilloscope preamplifier includes N inputs and Z outputs. A programmable cross-point multiplexer provides a first operating mode in which each of N inputs is connected to a different output thereby providing a preamplifier with Z channels, a second operating mode in which one input is multiplexed to all the outputs which are interleaved to maximize the sampling rate, and a range of operating modes in between. The programmable multiplexer includes a switching amplifier connected between each input and each output. Dials on the preamp select the mode by causing a microprocessor to program latches which activate or deactivate the switching amplifiers. A voltage divider is connected across inputs of the multiplexer to provide a programmable attenuator with selectable attenuation levels.

Abstract: A digitizer circuit for converting analog waveforms displayed upon a CRT screen into digital signals suitable for storage in memory employs a microprocessor to determine, from user-specified parameters, the times at which the output of the CRT vertical amplifier is to be sampled. The user has great flexibility in defining sample resolution and the location of the sample window on the displayed waveform in which the samples are to be taken and is permitted to intensify the sample window on the CRT display before any samples are taken in order to view the sample window in relation to the remainder of a displayed waveform.