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    • 5. 发明授权
    • Intrusion detection radar system with amplitude and frequency carrier
modulation to eliminate targets at short and long ranges
    • 入侵检测雷达系统具有幅度和频率载波调制,可消除短距离和远距离目标
    • US4697184A
    • 1987-09-29
    • US578539
    • 1984-02-09
    • James ChealJames R. FitzsimmonsEdward J. Foley
    • James ChealJames R. FitzsimmonsEdward J. Foley
    • G01S13/56G01S13/38G08B13/24
    • G01S13/56
    • An outdoor microwave transceiver area intrusion detection system includes circuitry for both amplitude and frequency modulation of the microwave carrier signal pulses, which are transmitted at approximately a 50% duty cycle pulses, from a radar antenna to a target. The return signal is mixed with a portion of the transmitted signal to produce first and second doppler frequency signals which are amplified and sampled during a narrow gating pulse. The two resulting sampled doppler frequency signals are alternately switched, in synchronization with the amplitude and frequency modulation signals, into first and second sample/hold circuits to reconstruct the first and second doppler frequency signals. The reconstructed signals are coupled to a differential amplifier to obtain a "range signal" which is proportional to the phase difference between the first and second doppler signals. The range signal is amplified and used to set an alarm circuit if its amplitude exceeds a certain threshold level for a certain interval of time. Signals from "close in" targets, due to rain on the radome surface and the like, are eliminated by the low value of the range signal. Signals from distant targets are cut off by the narrow gating pulse.
    • 室外微波收发机区域入侵检测系统包括用于从雷达天线到目标以大约50%占空比脉冲传输的微波载波信号脉冲的幅度和频率调制的电路。 返回信号与发射信号的一部分混合,以产生第一和第二多普勒频率信号,其在窄选通脉冲期间被放大和采样。 将两个产生的采样多普勒频率信号与幅度和频率调制信号同步地交替地切换到第一和第二采样/保持电路中以重构第一和第二多普勒频率信号。 重构的信号被耦合到差分放大器以获得与第一和第二多普勒信号之间的相位差成比例的“范围信号”。 范围信号被放大并用于设置报警电路,如果其幅度在一定时间间隔超过某个阈值电平。 “靠近”目标的信号由于雷达罩表面上的雨等而被消除,因为距离信号的低值。 来自远处目标的信号被狭窄的门控脉冲切断。