Doppler data processor with digital computing pulse rate filter

Claim 1

A doppler data processor apparatus for processing frequency burst type data produced to a laser doppler velocimeter comprising in combination: an analog filter unit to receive an output doppler data burst, said analog filter unit filtering said input doppler data burst to attenuate extraneous noise, said analog filter unit providing doppler burst data in response to said input doppler data burst, a sampling unit connected to said analog filter unit to receive said doppler burst data, said sampling unit providing a D pulse and a Delta pulse signal of four and eight doppler time periods respectively, a time base unit to provide clock pulses, and a digital pulse rate computing filter connected to said sampling unit to quantize the time interval of said D and Delta pulse signals, said digital pulse rate computing filter receiving said clock pulses to provide a time base, said digital pulse rate computing filter utilizing said time base and said time interval of said D and Delta pulse signals to establish predetermined doppler period limits, said digital pulse rate computing filter comparing the time interval difference between the D and Delta pulse signals with said predetermined doppler period limits, said digital pulse rate computing filter accepting valid doppler period data.