Patent ID: 7254494

Claim:
A method to obtain an ultrasonic measurement signal having an improved signal to noise ratio to determine characteristics of a fluid flow, the method comprising transmission of a predefined timed sequence of a number of ultrasonic burst signals at a first transducer, the burst signals being transmitted within a fluid flow, wherein the time periods between subsequently transmitted burst signals of said sequence are set according to a non-uniform pattern, wherein at least one time period differs from an other time period, and reception of a signal representing said transmitted sequence of ultrasonic burst signals at a second transducer, addition of multiple time-shifted copies of the received signal to said original received signal to obtain a sum of the original received signal and its time-shifted copies, wherein the time shift of a copy is related to said predefined pattern, and providing a reconstruction of an original burst signal having an improved signal to noise ratio from said sum to determine characteristics of the fluid flow.