Abstract: Doppler radar sets of the type including circuitry for determining and displaying sense of target motion along the radar beam. The Doppler phase shifters in the I and Q channels of pulse radars of this type are designed to operate at frequencies much higher than the Doppler baseband frequencies by selecting one of the Doppler sidebands of the radar's pulse repetition frequency, or one of the sidebands of a harmonic of such pulse repetition frequency, for application to said Doppler phase shifters. The higher operating frequency simplifies the design and construction of the Doppler phase shifters.

Abstract: Interference between radar systems is eliminated by using shaped pulses. In one embodiment, the pulse has a cosine shape, in another a cos.sup.2 shape and in a third embodiment a cos.sup.n shape. In yet another embodiment, a single sideband shaped pulse is employed.

Abstract: A Doppler radar system in which quadrature Doppler signals are derived to eld directional information. The quadrature signals are derived by demodulating the return signals with respective odd and even harmonics of the sinusoidal signal used to frequency modulate the RF carrier.

Abstract: Interference between two or more radar systems operating on the same freqcy is eliminated by synchronizing the rotation of the scanning antennas. In another embodiment, each transmitter is blanked if the corresponding receiver detects an interfering signal from the other transmitter. In yet another embodiment, the transmitter pulses are not blanked but merely delayed, if a pulse is received from the interfering system.