Measurement circuit for digital to analog converter
AssigneeHewlett-Packard Company
InventorToshio Tamamura
Life of this patent
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Abstract
A device for evaluating the accuracy and dynamic response of a digital to analog converter (DAC). A digital word generator which provides inputs to the DAC and a sampler which samples the analog output signal from the DAC are triggered by a stream of clock pulses. Clock pulses for the sampler pass through a fixed delay line, to provide time for the DAC to stabilize. Clock pulese for the digital word generator pass through a pulse swallower capable of eliminating clock pulses to phase shift the digital word input to the DAC one step with respect to the sampler trigger signal, to move the sampling point to the next step in the cycle of the digital input waveform.
Claims4
Apparatus for measuring characteristics of a digital to analog converter (DAC) by measuring a periodic analog output signal produced by the DAC in response to a sequence of a digital input words while the DAC is operating at a high converting rate, comprising:
- clock pulse generating means;
- a digital word generator, triggered by the clock pulses, for providing a periodic sequence of digital input words to the DAC;
- sampling means, responsive to the clock pulses, for sampling the periodic analog output signal from the DAC at a sampling point having a constant delay time with respect to the triggering time of the digital word generator, to produce sampled analog values;
- and
- pulse swallowing means, connected between the clock pulse generating means and the digital word generator, for selectively eliminating clock pulses to shift the sampling point from the analog output corresponding to one digital input word to the analog output corresponding to a different digital input word from the DAC, without altering the delay time of the sampling point with respect to the triggering time of the digital word generator.
Dependencies are inferred from the claim text.