Doppler radar system
AssigneeU.S. Philips Corporation
InventorKenneth Holford
Life of this patent
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Abstract
A Doppler radar system for controlling portable traffic signals in response to on-coming traffic. Each of two channel amplifiers of the system is fixed at high gain and passes both noise signals and Doppler signals to a phase detector. A threshold element provides a control signal when the average level of the phase detector output between high and low levels changes sufficiently, due to the presence of Doppler signals, from a mean level which is due to noise alone.
Claims9
A Doppler radar system comprising a phase detector responsive during each beat signal cycle to produce an output signal having a first level when the two beat signals have a relative phasing within specified limits and a second level when their relative phasing has shifted outside these limits, respective amplifying means to which said beat signals are applied before application to said phase detector, said amplifying means having a gain sufficient to produce, in the absence of said beat signals, output noise signals which are due to noise in the system and which render the phase detector responsive in accordance with the relative positions of their rising and falling edges to produce its output signal with either said first or second level, storage means responsive to the phase detector output signal for storing a representative level thereof, and threshold means responsive to provide an indication of a moving target when said representative level of output signal changes from a quiescent value to a threshold value.
Dependencies are inferred from the claim text.