The feedback amplifier of the oscillator is alternately biased between an oscillating and a non-oscillating state with an input signal from a bias network. Accordingly, a desirable feature of a radar detector is that it produce a quiescent signal which is nearly independent of the environment.Ä«RIEF SUMMARY OF THE INVENTION Briefly, my invention comprises a radar detector in which a pulsed oscillator includes a feedback amplifier having an input, an output, and a feedback pathconnecting the input to the output. A signal differing a predetermined amount from the quiescent signal reference thus corresponds to a condition in the space characteristic of an intrusion. ![]() This or any other quiescent signal such as a signal representative of the oscillator repetition rate can conveniently be employed as a reference for detecting an intrusion condition. If conditions within the space are quiescent, the received rf energy produces a signal in the receiving antenna which is unchanging. Commonly this circuit consists of the combination of an antenna which receives energy reflected by the environment (objects and surfaces which are located within and define the boundaries of the space) and a detector which responds to a predetermined change in the energy received by the antenna. A circuit is provided for receiving rf energy from the space and for providing an indication when the received energy corresponds to an intrusion into the space. In such applications, a detector propagates a wave in the form of pulses of radio frequency (rf) energy into the space to be protected. Such detectors are, for example, employed in security systems for what is sometimes referred to as space protection. G01S13/10- Systems for measuring distance only using transmission of interrupted, pulse modulated waves.G01S13/08- Systems for measuring distance only.G01S13/06- Systems determining position data of a target.G01S13/02- Systems using reflection of radio waves, e.g.radar systems Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified G01S13/00- Systems using the reflection or reradiation of radio waves, e.g.G01S- RADIO DIRECTION-FINDING RADIO NAVIGATION DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES ANALOGOUS ARRANGEMENTS USING OTHER WAVES.238000004519 manufacturing process Methods 0.000 description 1.229910000529 magnetic ferrite Inorganic materials 0.000 description 1. ![]()
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