Sampling wave-form digitizer for dynamic testing of high speed data conversion components

A sampling waveform digitizer for testing a waveform under test that is developed by a Device Under Test (DUT) in response to a test stimulus, the sampling waveform digitizer comprising:

• (a) a comparator/integrator loop having an inverting input (43), a noninverting input (44), a strobe input (42), and an output (33), said inverting input for accepting the waveform under test;
• (b) a test signal generator having an output for coupling the test stimulus to the DUT;
• and
• (c) programmable delay means having an input coupled to an output of the test signal generator and having an output coupled to the strobe input of the comparator/integrator loop for supplying to the strobe input a sequence of strobe pulses having a controlled phase relative to the waveform under test, so that, in response to the sequence of strobe pulses, the comparator/integrator loop samples the waveform under test until the signal at output (33) assumes a predetermined relationship with respect to the waveform under test at a time/point at which the waveform under test is sampled.

A method for characterizing a Device Under Test (DUT), the method comprising the steps of:

• (a) applying a test stimulus signal to the DUT so that the DUT generates a test waveform;
• (b) coupling the test waveform to a first input of a latching comparator;
• (c) coupling a signal related to the test stimulus signal to a programmable delay element so that the programmable delay element generates a sequence of strobe pulses;
• (d) coupling the strobe pulses to a strobe input of the latching comparator so that the latching comparator samples the test waveform in response to the strobe pulses;
• (e) integrating the output of the latching comparator so as to generate an integrated signal;
• (f) coupling the integrated signal to a second input of the latching comparator;
• and
• (g) controlling the operation of th programmable delay element so that the strobe pulses are generated at times that cause the value of the integrated signal to exhibit a predetermined relationship with respect to the value of the test waveform as sampled by the latching comparator.

A sampling waveform digitizer for testing a waveform under test, the sampling waveform digitizer comprising:

• (a) a comparator/integrator loop having an inverting input (43), a noninverting input (44), a strobe input (42), and an output (33), said inverting input for accepting the waveform under test;
• (b) programmable delay means having an output coupled to the strobe input of the comparator/integrator loop for supplying to the strobe input a sequence of strobe pulses having a controlled phase relative to the waveform under test so that, in response to the sequence of strobe pulses, the comparator/integrator loop samples the waveform under test until the signal at output (33) assumes a predetermined relationship with respect to the waveform under test at a time/point at which the waveform under test is sampled;
• and
• (c) control means coupled to the programmable delay means for controlling the time/point at which strobe pulses are supplied to the strobe input of the comparator/integrator loop.

A method for characterizing a test waveform, the method comprising the steps of:

• (a) coupling the test waveform to a first input of a latching comparator;
• (b) causing a programmable delay element to generate a sequence of strobe pulses;
• (c) coupling the strobe pulses to a strobe input of the latching comparator so that the latching comparator samples the test waveform in response to the strobe pulses;
• (d) integrating the output of the latching comparator so as to generate an integrated signal;
• (e) coupling the integrated signal to a second input of the latching comparator;
• and
• (f) controlling the operation of the programmable delay element so that the strobe pulses are generated at times that cause the value of the integrated signal to e exhibit a predetermined relationship with respect to the value of the test waveform as sampled by the latching comparator.