A jitter generator produces a jittery test signal for use in performing a
jitter test on an integrated circuit (IC) device under test (DUT). The
jitter generator includes a programmable delay circuit for delaying a
non-jittery input signal with a varying delay controlled by input digital
delay control data to produce the test signal. A pattern generator
supplies a sequence of delay control data to the programmable delay
circuit causing it to produce a desired jitter pattern in the test
signal. During a calibration process, a measurement unit feeds the test
signal back to the input of the programmable delay circuit, causing the
test signal to oscillate with a period proportional to the delay through
the delay circuit. The measurement unit then measures the period of the
test signal for various values of delay control data and reports
measurement results. Based on the measurement results, host equipment
then determines an appropriate sequence of delay control data for
producing a desired jitter pattern in the test signal and programs the
pattern generator to produce that sequence of delay control data during a
jitter test. The jitter generator can form a part of a built-in,
self-test (BIST) circuit implemented within the DUT itself.