Fast low frequency jitter rejection methodology

A measurement instrument configured to measure at least one signal characteristic associated with at least one signal under test, said measurement instrument comprising:

• an input circuit adapted to receive at least one signal under test from a device under test and a reference signal;
• a processor circuit coupled to said input circuit, said processor circuit configured to control the input circuit to alternately sample the at least one signal under test and the reference signal in an interleaved fashion such that the signal under test is sampled in one block and the reference signal is sampled in a subsequent block;
• and wherein the alternate sampling process implemented by the input circuit is repeated until N samples of the at least one signal under test and the reference signal are collected in a series of interleaved sampled waveform blocks, for some positive integer N;
• at least one measurement channel coupled to said input circuit and to said processor circuit, said at least one measurement channel adapted to receive the series of interleaved sampled waveform blocks from the input circuit and to measure at least one signal characteristic of the interleaved sampled waveform blocks, wherein said processor circuit is further configured to average selected samples obtained from the at least one signal under test;
• average selected samples obtained from the reference signal;
• and subtract the average of the selected reference signal samples from the average of the selected signal under test samples.

A method of measuring signals provided from a device under test to reduce low frequency measurement instrument noise, said method comprising the steps of:

• providing at least one signal under test from a device under test to a measurement instrument;
• providing a reference signal to the measurement instrument;
• alternately sampling the at least one signal under test and the reference signal in an interleaved fashion such that the signal under test is sampled in one block and the reference signal is sampled in a subsequent block;
• repeating the alternate sampling process until N samples of the at least one signal under test and the reference signal are collected in a series of interleaved sampled waveform blocks, wherein N is a positive integer;
• measuring at least one signal characteristic of the interleaved sampled waveform blocks;
• providing an output indicative of the at least one measured signal characteristic;
• and
• wherein the time duration of each sampled block of the at least one signal under test and the reference signal is at least ten times smaller than the inverse of an upper threshold of the low frequency noise that is to be reduced.