Transmission reception system for frequency-agile doppler radars

Abstract

A transceiver system of a frequency-agile Doppler radar comprises a transmission-side and a reception-side oscillator circuit both connected to a frequency-agility controller for concurrently varying their operating frequencies. Each of these oscillator circuits includes a high-frequency generator coupled via a frequency divider and a frequency multiplier to a pair of auxiliary mixers in a control loop of an associated microwave generator, the loop further including another frequency divider between the two mixers. The step-down ratios of the two frequency dividers of each oscillator circuit is adjustable by the frequency-agility controller. The microwave generator of the transmission-side oscillator circuit emits an outgoing signal to a duplexer connected to the radar antenna while incoming echoes are fed by the duplexer to a first principal mixer receiving a heterodyning signal from the microwave generator of the reception-side oscillator circuit. The reception-side high-frequency generator has a fixed operating frequency while its transmission-side counterpart is voltage-controlled by a phase loop including a second and a third principal mixer in cascade with each other. The second principal mixer receives the output signals of the two frequency multipliers while the third principal mixer introduces a frequency-transposition signal from a Doppler oscillator into that phase loop; the Doppler oscillator is controlled by a frequency discriminator receiving the output signal of the first principal mixer through a narrow-band filter.

Dependencies are inferred from the claim text.