obtaining a plurality of measurements, using at least one measurement channels system, for a plurality of selected signal edges within a transmitted data stream, wherein the transmitted data stream comprises a repeating data pattern, wherein each iteration of the data pattern has a given number of multiple pulses, wherein each iteration of the data pattern does not correspond to uniform repetition of a single pulse, and wherein the time difference between adjacent measurements is determined by an event count increment equal to an integer multiple (M) of the given number of multiple pulses within the repeating data pattern;

computing a time interval error (TEI) value, using a processor circuit, for each measured signal edge in said obtaining step;

transforming TIE values, using the processor circuit, into corresponding TIE components for selected of the measured signal edges, wherein said TIE frequency components are representative of both noise floor as well as multiple distinct frequency peaks;

separating the noise floor from the multiple distinct frequency peaks, using the processor circuit;

computing the power of the noise floor within the TIE frequency components, using the processor circuit; and

providing an output indicative of the computed power of the noise floor to obtain an estimate of the random jitter variance using the processor circuit.