LASER DOPPLER SPEED METER Russian patent published in 1996 - IPC

FIELD: control and test methods used for measurement of movement speed of light scattering surfaces, liquids and gasses. SUBSTANCE: output electrical signal of meter optical sensor is fed to inputs of quadrature converter of Doppler signal, that has two mixers, quadrature generator of carrier and two output filters of lower frequencies, from output of which signal is fed to inputs phase comparator and to inputs of first and second squarers exercising doubling of information signal frequency. Signal from squarers output is fed to inputs of adder and subtracter, that together with connected to its output divider forms first subtracter of circuit of M in series connected analog computers exercising functions of conversion upward of Doppler signal carrier and normalization of its amplitude. EFFECT: improved quality and accuracy of measurements.