PURPOSE: To lengthen the maximum detectable distance, and improve S/N by restricting a reception signal band by means of a filter by which center frequency is changed in the front stage of a pulse compressor according to frequency deviation of a transmission pulse signal.
CONSTITUTION: Preset voltage corresponding to center frequency being inputted to a voltage adder 19 for initial acquisition is set by manual operation, and a dynamic tracking filter DTF 16 is set in passage band width having prescribed center frequency. Here, when a reception IF signal is transmitted from an IF amplifier, it passes through the DTF 16, and a level detector 17 detects a significant level, and outputs a set pulse. When a sawtooth wave generator 18 receives the set pulse, it generates a sawtooth wave having a prescribed inclination, and changes the center frequency of the DTF 16 in an inclination (frequency deviation quantity/pulse width of long pulse), and sends wave filtered output based on this center frequency to a pulse compressor. Here, since a pulse uncompressed signal is a linear frequency modulated signal, the band width of the DTF 16 can be set sufficiently narrowly, so that S/N can be improved.
ICHIKAWA MITSURU
FUJIWARA TOMOHIRO
ICHIKAWA MITSURU
MITSUBISHI ELECTRIC CORP
| JPH01102382A | 1989-04-20 |