| 摘要 |
A target detecting and ranging system of the type transmitting search pulses and receiving echo pulses is disclosed. The system employs an input receiver receiving return signals and feeds them to an extracting circuit, a gate and cancellation circuit. The extracting circuit, functions to supply an input to the gate of signals containing relevant information such that gate output is only irrelevant information. The cancellation circuit, receiving the gate output and the return signals, eliminates irrelevant signals by mutual cancellation. The circuit for extracting relevant signals comprises in one embodiment a differentiator, analog store and parallel adder with a shaping circuit, clipping the output below a threshold level. Digital implementation is also discribed. The differentiator may also be replaced by a compression circuit. In a second embodiment of the system an integrator is interposed between the gate and the cancellation circuit. The integrator has a long time constant for short duration return pulses, that is containing relevant data and a short time constant for long duration pulses and functions to improve shaping of the irrelevant signals supplied to the cancellation circuit. The output of the cancellation circuit to both embodiments is fed to an amplifier and then to a display device.
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