Abstract: A charge coupled device (CCD) with separately addressable input signal gates is operated in the potential equilibrium mode. With properly selected voltage potentials the CCD can be used as a high speed linear detector of a variable analog signal without the need of preceeding independent sample and hold or peak detector circuits. The result is the efficient minimum/maximum detection of an analog signal in a fast-in/slow-out digitizer.

Abstract: A signal-envelope display system for a digital oscilloscope includes a memory for storing minimum and maximum signal values in adjacent storage locations, an address counter for sequentially addressing the memory, and a control circuit for selectively inverting the least significant bit of the address count signal. The values retrieved from the memory are converted to analog values and a low-pass filter connects the analog values to provide a signal envelope display.

Abstract: A waveform storage system is provided in which waveform envelopes or maximum signal deviations along a waveform are detected and stored. A sampling clock operates at a predetermined fixed rate independently of a recording clock which is operable at rates determined by the sweep speed and is equal to or slower than the sampling clock. Data from an analog-to-digital converter is simultaneously applied to at least one latch and at least one comparator to be compared with the latch output. If the absolute value of the signal is greater than that stored in the latch, the latch is updated with the new value. The contents of the latch are clocked into memory by the recording clock.

Abstract: A display system for a digital oscilloscope includes an interpolator for interpolating between stored waveform samples and providing additional samples at the interpolated values to thereby increase dot density of the resulting display.

Abstract: Jitter due to sample uncertainty in a digital oscilloscope is reduced by horizontally shifting each frame of a repetitive waveform display to provide an apparent time coincidence of each frame. The time interval between a fixed point on the successive waveforms and the next succeeding clock edge is measured, and a correction voltage is produced to offset the sweep voltage by the corrected amount.