| 摘要 |
An instantaneous gain controlling system particularly for coherent (MTI) radar systems. A gain controllable intermediate frequency amplifier, a COHO, and a phase detector are shown along with an MTI canceller which itself includes a delay device and a differencer are shown. The delay device provides a full pulse repetition period of delay, and the differencer operates to subtract the coherent video at the phase detector output from the same signal train, one pulse repetition interval earlier, to provide MTI cancellation. The delayed video train is full wave rectified, passed through a threshold circuit and an adjustable gain video amplifier and used as a pulse-by-pulse gain controlling signal for the intermediate frequency amplifier. Large signal blocks are thus prevented from overloading the receiver channel with consequent spectral spreading and MTI cancellation degradation.
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