Technique for computing a measure on an ultrasonic signal having application to identify valve defects in operating engines

A method of generating a number value representative of the width of a noisy pulse in an analog signal, where the analog signal is a down-converted ultrasonic signal emitted from a cylinder of a locomotive engine, said method comprising:

• sampling the analog signal at predetermined sample intervals to generate a sampled signal including samples;
• creating bunches of successive samples in the sampled signal over a predetermined bunched sample period to generate a sequence of bunched samples;
• generating a root mean square of each bunched sample;
• multiplying at least two successive bunched samples to generate a first product value;
• cubing each root mean squared bunched sample to generate a second product value;
• averaging the first product value and the second product value over a plurality of product values to generate a first averaged product value and a second averaged product value;
• and
• ratioing the first averaged product value and the second averaged product value to generate the number value.

A system for generating a number value representative of the width of a noisy pulse in an analog signal, said system comprising:

• a sampling device for sampling the analog signal at predetermined sample intervals to generate a sampled signal including samples;
• a bunching device for bunching successive samples in the sampled signal over a predetermined bunched sample period to generate a sequence of bunched samples;
• and
• a first multiplying device for multiplying the bunched samples over at least two successive bunched sample periods to generate a first product value, where the first product value is representative of the width of the noisy pulse.