Pulse measurement circuit

In a measuring instrument, a pulse measurement circuit for measuring a timing parameter of a pulse on an input signal, comprising:

• a main trigger generator for generating a main trigger signal in response to a parameter boundary of the pulse;
• a delayed trigger generator for generating a delayed trigger signal in response to a parameter boundary of the pulse;
• first adjustable delay means for sensing the main trigger signal and in response enabling the delayed trigger generator to trigger after a selectable delay;
• second delay means for delaying passage of the pulse to the delayed trigger generator until after the pulse has passed to the main trigger generator, the second delay means allowing the delayed trigger generator to be enabled by the first delay means and trigger on the same pulse as the main trigger generator for a predetermined delay;
• measurement means for measuring a first time between the main and delayed trigger signals when both are adjusted to trigger on the same pulse at a first parameter boundary and for measuring a second time between trigger signals when one generator is adjusted to trigger on the first boundary and the other generator is adjusted to trigger on a second parameter boundary;
• and
• controller means for subtracting the first time measurement from the second time measurement to measure the time of the pulse parameter.

A method of measuring a timing parameter of an input signal pulse to a measuring instrument, the instrument having a main trigger generator and a delayed trigger generator, comprising:

• causing the main and delayed trigger generators to trigger on the same pulse at a first parameter boundary;
• measuring a first time between generation of the trigger signals;
• causing one of the generators to trigger at a second parameter boundary while the other again triggers on the first parameter boundary;
• measuring a second time between generation of the trigger signals;
• and
• subtracting the first time measurement from the second time measurement to measure the time of the pulse parameter.