Long range police radar warning receiver with multiple array averaging
First Claim
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1. A police radar warning receiver comprising:
- receiver means for producing a sweep pattern as an oscillator signal is swept in frequency between a first frequency and a second frequency in response to mixing of received RF signals in at least one band of police radar signal frequencies with said swept oscillator signal;
circuit means responsive to the receiver means for producing at various intervals over each sweep of the oscillator signal a respective magnitude word, each magnitude word being a relative measure of signal energy at a respective interval;
first averager means for accumulating with respect to each of at least a plurality of said intervals and in accordance with a first weighting factor, a first average of the magnitude word associated with a said interval over a plurality of sweeps of the oscillator signal whereby to produce a first array of averager words;
second averager means for accumulating with respect to each of at least a plurality of said intervals and in accordance with a second weighting factor, a second average of the magnitude word associated with a said interval over a plurality of sweeps of the oscillator signals whereby to produce a second array of averager words; and
alarm enable means responsive to said first and second averager means for providing an alarm enable if, after a given sweep of the oscillator signal, either (1) a first averager word in said first array meets at least a first criterion, or (2) a second averager word in said second array meets at least a second criterion, whereby to indicate receipt of a police radar signal.
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Abstract
A police radar warning receiver includes a DSP circuit having a correlator, multiple array averager and a peak detector to provide after each sweep of a swept local oscillator respective dynamic thresholds associated with each averager array and against which information from that sweep is evaluated to determine whether to generate an alarm enable indicative of receipt of a police radar signal. The multiple averager arrays allow for different averaging or weighting ratios to maximize sensitivity of the receiver on the one hand and enhance response time on the other rather than trading off one for the other.
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Citations
23 Claims
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1. A police radar warning receiver comprising:
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receiver means for producing a sweep pattern as an oscillator signal is swept in frequency between a first frequency and a second frequency in response to mixing of received RF signals in at least one band of police radar signal frequencies with said swept oscillator signal; circuit means responsive to the receiver means for producing at various intervals over each sweep of the oscillator signal a respective magnitude word, each magnitude word being a relative measure of signal energy at a respective interval; first averager means for accumulating with respect to each of at least a plurality of said intervals and in accordance with a first weighting factor, a first average of the magnitude word associated with a said interval over a plurality of sweeps of the oscillator signal whereby to produce a first array of averager words; second averager means for accumulating with respect to each of at least a plurality of said intervals and in accordance with a second weighting factor, a second average of the magnitude word associated with a said interval over a plurality of sweeps of the oscillator signals whereby to produce a second array of averager words; and alarm enable means responsive to said first and second averager means for providing an alarm enable if, after a given sweep of the oscillator signal, either (1) a first averager word in said first array meets at least a first criterion, or (2) a second averager word in said second array meets at least a second criterion, whereby to indicate receipt of a police radar signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of detecting a police radar signal comprising:
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repeatedly sweeping an oscillator between a first frequency and a second frequency; producing a sweep pattern by mixing received RF signals in at least one band of police radar signal frequencies with said sweeping oscillator signal; producing at various intervals over each sweep of the oscillator signal a respective magnitude word, each said magnitude word being a relative measure of signal energy at a respective interval; accumulating with respect to each of at least a plurality of said intervals and in accordance with a first weighting factor, a first average of the magnitude word associated with a said interval over a plurality of sweeps of the oscillator signal whereby to produce a first array of averager words; accumulating with respect to each of at least a plurality of said intervals and in accordance with a second weighting factor, a second average of the magnitude word associated with a said interval over a plurality of sweeps of the oscillator signal whereby to produce a second array of averager words; providing, after a given sweep of the oscillator signal, an alarm enable if either (1) first averager word in said first array meets a first criterion, or (2) a second averager word in said second array meets a second criterion, whereby to indicate receipt of a police radar signal. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A police radar warning receiver comprising:
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receiver means for producing a sweep pattern as an oscillator signal is swept in frequency between a first frequency and a second frequency in response to mixing of received RF signals in at least one band of police radar signal frequencies with said swept oscillator signal; circuit means responsive to the receiver means for producing at various intervals over each sweep of the oscillator signal a respective magnitude word, each magnitude word being a relative measure of signal energy at a respective interval; a plurality of averager means each for accumulating, with respect to each of at least a plurality of said intervals and in accordance with an associated weighting factor, an average of the magnitude word associated with a said interval over a plurality of sweeps of the oscillator signal whereby to produce a plurality of arrays of averager words; and alarm enable means responsive to said plurality of averager means for providing an alarm enable if, after a given sweep of the oscillator signal, an averager word in at least a selected one of said arrays meets at least a first criterion, whereby to indicate receipt of a police radar signal.
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22. A police radar warning receiver comprising:
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receiver means for producing a sweep pattern as an oscillator signal is swept in frequency between a first frequency and a second frequency in response to mixing of received RF signals in at least one band of police radar signal frequencies with said swept oscillator signal; circuit means responsive to the receiver means for producing at various intervals over each sweep of the oscillator signal a respective magnitude word, each magnitude word being a relative measure of signal energy at a respective interval; first averager means for accumulating over a plurality of sweeps of the oscillator signal not more than about 5% of the value of the magnitude word in each sweep associated with at least one said interval; second averager means for accumulating over a plurality of sweeps of the oscillator signal not less than about 50% of the value of the magnitude word in each sweep associated with at least one said interval, and; alarm enable means responsive to said first and second averager means for providing an alarm enable if, after a given sweep of the oscillator signal, the accumulated value in one of said averager means meets a criterion associated with that averager means, whereby to indicate receipt of a police radar signal. - View Dependent Claims (23)
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Specification