PURPOSE: To increase radiant energy and improve S/N by sweeping the frequency of a transmit radio wave linearly to specific frequency width, and mixing its transmit signal and receive signal by a mixer and then knowing the time difference up to the transmission point from the frequency of the generated single frequency signal.
CONSTITUTION: A reflected ratio wave received by a receiving antenna 9 is supplied to a balance transformer 11 for balance-unbalance conversion, and its output is amplified by a wide band amplifier 12 and supplied to the mixer 13. The mixer 13 is supplied with a frequency sweep signal which is swept from f1 to fn from a sweep signal oscillator 1 and a signal of f0+fn for the sum or (f1+f0+ fn)W(f2+f0+fn) for the difference is led out. Here, fn=Δf×τ/Δt, where Δf=f2- f1, Δt is sweep time width, and is the delay time of the receive signal. The output of the mixer 13 is supplied to a band-pass filter 14 to obtain a signal of f0+ fn. This signal is amplified to increase the S/N ratio and then mixed with f0 to lead a signal of fn proportional to τ out of a low-pass filter 17. Consequently, the radiation time of a radio wave is made long and the radiant energy is increased.
ARAI IKUO
ASAKURA MASAO
NOZU TOSHIMITSU
ARAI IKUO
KODEN ELECTRONICS CO LTD
| JPS51113490A | 1976-10-06 |