PURPOSE: To increase radiant energy by using a transmit radio wave as a frequency sweep signal, and discriminating between a transmit and a receive signal from a frequency shift corresponding to the time difference between the transmit radio wave and a reflected wave and extending the continuance of the transmit signal as a result.
CONSTITUTION: The receive signal Pc is frequency-converted and supplied to a pulse generating means 16. The pulse generating means 16 is composed of a matched filter which has such characteristics that the delay time decreases grdually by a specific value at every time in the increasing direction of a frequency (f). The delay characteristics A of this matched filter gives delay times t2Wt1 to frequency-converted receive signals Ph of minimum frequency fL1W maximum frequency fL2. Those delay times t2Wt1 are selected exactly in the opposite relation with delay characteristics B obtained by frequency sweeping. This matched filter is supplied with the output signal of a holding circuit 15 to make all frequency components of a low frequency receive signal Ph into pulses integrally at one point of time. The generation point of the pulses is proportional to the delay amount of the receive signal Pc.
ARAI IKUO
ASAKURA MASAO
NOZU TOSHIMITSU
ARAI IKUO
KODEN ELECTRONICS CO LTD