ABSTRACT
The primary task of the signal processor is to extract the frequency information from the burst signal generated by a particle passing through the measuring volume, and provide an analog or digital output proportional to the frequency of the signal. The unique nature of the signals demands the use of a special signal processing system to extract the velocity information. The flow velocity is "sampled" by the particle passing through the measuring volume, and the velocity measurement is obtained only when the Doppler signal, created by the particle, is processed and output as a data point by the signal processor. If the actual data rate is so high that the output data is essentially able to characterize the flow (time history), then the output can be sampled at uniform time increments. This is similar to the procedure normally used for sampling a continuous analog signal using an ADC.
