dipositivo for measuring the distance and the speed of approach or departure of a moving target

摘要

A radio range measuring apparatus having a controlled modulation slope in order to keep the beat frequency between the transmitted signal and the received signal constant. The apparatus also measures the speed at which a mobile target approaches or recedes by means of a generator of a fixed frequency which, after frequency division, maintains the duration between the start of two consecutive sawtooth modulation signals fixed. A particular spectral line of the beat signal is demodulated by this fixed frequency via a mixer whose output is filtered by a passband filter. The signal at the output of the filter has a frequency which is equal to the Doppler frequency, proportional to the speed.