Phase coherent decoy radar transmitter

摘要

A decoy radar transmitter governed by a control signal derived from a main radar transmitter to emit radiation which is phase coherent with the carrier frequency of the main radar transmission is disclosed. A section of the main radar transmitter generates a control signal compositely formed by the combination of derived signals including a phase coherent subharmonic of the carrier frequency of the main radar, a frequency shift keyed signal and a signal having a power content. The frequency shift keyed signal is representative of a phase coded modulation sequence of the carrier frequency transmissions, each frequency fo the frequency shift keying corresponds to a phase polarity of the phase coding. A single coaxial cable conducts the composite control signal to the decoy radar transmitter. Upon receiving the composite control signal, a section of the decoy radar transmitter separates the power signal from the received control signal for use in energizing the decoy radar transmitter. The other signals are also separated from the compositely received control signal, whereupon the separated phase coherent subharmonic is frequency multiplied to approximately the carrier frequency of the main radar and the frequency shift keyed signal is frequency discriminated to obtain the phase coding sequence. Thereafter, the frequency multiplied phase coherent subharmonic is modulated with the obtained phase coding sequence to form a signal which governs the radar emissions of the decoy radar transmitter.