초록 ▼

The signal delivered by a Doppler sensor is treated after amplification, filtering and digitization by: means for determining the global energy of the digitized signal; autocorrelation test means for showing up a dominant frequency; a filter for rejecting that frequency; comparators for eliminating

The signal delivered by a Doppler sensor is treated after amplification, filtering and digitization by: means for determining the global energy of the digitized signal; autocorrelation test means for showing up a dominant frequency; a filter for rejecting that frequency; comparators for eliminating signals having energy less than a threshold; a filter for isolating a particular frequency band; and means for intercorrelation with a reference signal held in memory.

대표청구항 ▼

[ There is claimed:] [1.] A method of detecting the presence of a living being of a particular species, in a monitored space in which there is disposed a microwave Doppler sensor supplying a low-frequency signal produced by beating between a transmitted wave and a reflected wave frequency shifted by

[ There is claimed:] [1.] A method of detecting the presence of a living being of a particular species, in a monitored space in which there is disposed a microwave Doppler sensor supplying a low-frequency signal produced by beating between a transmitted wave and a reflected wave frequency shifted by the Doppler-Fizeau effect by a moving target in the monitored space, wherein said signal from said sensor, after any necessary amplification and filtering, is digitized and processed to show up in the frequency spectrum of said signal peculiarities specific to the species of said living being in order to recognize the presence of a being of that species, and wherein the processing of said digitized signal comprises the following steps:a) determining the overall energy of said digitized signal and eliminating signals with energy less than a threshold energy;b) applying to the signal produced by step (a) at least one autocorrelation test adapted to detect the presence of a dominant frequency;c) filtering said digitized signal by means of an adaptive filter adjusted to reject said dominant frequency detected in step (b);d) determining the global energy of said signal produced by said filtering step (c) and eliminating signals having energy less than a threshold energy;e) filtering the signal from step (d) to isolate a particular frequency band that is stable and specific to movements of the particular species of said living being;f) applying to the signal from step (e) a test of temporal intercorrelation with a reference signal specific to the particular species of said living being and held in memory to define an interspectral energy and emitting at least one two-state signal corresponding to interspectral energies respectively greater than and less than a threshold energy.