Abstract: A measuring apparatus is provided in one of two objects moving relatively to each other. The apparatus includes a circuit for effecting a direct spread modulation with respect to a transmission carrier signal using modulation codes; an antenna unit for transmitting the modulated carrier signal toward the other of the two objects and for receiving a reflection wave therefrom; a circuit for demodulating the received reflection wave signal using the transmission carrier signal; a circuit for making correlation between the demodulated output signal and a signal having the same code as that of the modulation code and having a phase delayed by a predetermined time; a unit for extracting a Doppler frequency component contained in a signal which has been propagated through a propagation path existing in a specified distance range; and a circuit for properly processing the extracted Doppler frequency component.

Abstract: A speed measuring apparatus includes: a modulation circuit for carrying out a direct spread modulation with respect to a transmission carrier signal using coded two-phase random signals; an antenna unit for transmitting the modulated transmission carrier signal as a radio-wave toward an object and for receiving a reflected wave from the object; a demodulation circuit for demodulating a signal corresponding to the received reflected wave using the transmission carrier signal, to thereby generate intermediate frequency signals; a correlation circuit for making correlation between the intermediate frequency signals and signals each having the same code as that of the coded two-phase random signal and having a phase delayed by a predetermined time; a Doppler detecting unit for extracting from an output signal of the correlation circuit a Doppler frequency component contained in a signal which has been propagated by way of a propagation path existing in a specified distance range, and for generating speed informat