UNLOCKED W-BAND RECEIVER HAVING COHERENT FEATURE

摘要

PROBLEM TO BE SOLVED: To generate inter-pulse coherence by using an unlocked voltage- controlled oscillator by processing video signals and estimating the zero-offset from the center of the scanning pattern generated by an antenna. SOLUTION: A downward converter 30 downwardly converts reflected waves received 11 from radar equipment and generates corresponding video signals. After the video signals are filtrated 17 and converted 21 into digital signals 21, a digital IQ converting circuit 22 generates complex number sum and difference channel samples. After the sum and difference outputs of the circuit 2 are Fouriertransformed 23, a magnitude detector 24 detects the frequency of the signals. A peak detecting and center-of-gravity circuit 25 decides the center frequency offset of a transmitted frequency and supplies the offset to an unlocked voltage-controlled oscillator at the beam center from the transmitted frequency. A phase deciding circuit 26 decides the phase between the sum and difference signals and an angle estimating circuit 28 estimates the zero-offset from the center of a scanning pattern by using the magnitude, phase and zero- position algorithms of processed sum and difference reflected pulses.