Police radar signal band discrimination circuitry for a police radar warning receiver

Claim 2

A police radar warning receiver adapted to indicate presence in one of at least two bands of a police radar signal, the receiver comprising: oscillator means for generating an oscillator signal which is swept in frequency between a first frequency and a second frequency; mixer means for mixing said oscillator signal with a signal correlated to a received police radar signal to provide a primary IF signal and an image IF signal; filter means for passing one of said image IF and primary IF signals; and circuit means responsive to said passed IF signal adapted to indicate reception of the police radar signal and in which band the police radar signal is present.

Claim 3

The police radar warning receiver of claim 1 further comprising: antenna means for providing to said mixer means said signal correlated to a received police radar signal.

Claim 4

The police radar warning receiver of claim 1, said circuit means including: discriminator means responsive to said passed IF signal for generating an output signal having a level which varies relative to a threshold in one of a first and a second manner, said first manner defined by said level varying from above said threshold to below said threshold in response to said passed IF signal being generated by mixing said swept oscillator signal with a received police radar signal in a first band, said second manner defined by said level varying from below said threshold to above said threshold in response to said passed IF signal being generated by mixing said swept oscillator signal with a received police radar signal in a second band; and means coupled to the discriminator means for indicating that the received police radar signal is in (1) the first band when said level varies in said first manner and (2) the second band when said level varies in said second manner.

Claim 5

The police radar warning receiver of claim 1, said circuit means including: second oscillator means for generating a second oscillator signal at a predetermined frequency; second mixer means for mixing said second oscillator signal with said passed IF signal to provide a second IF signal; and second circuit means responsive to said second IF signal to indicate reception of the police radar signal and in which band the police radar signal is present.

Claim 6

The police radar warning receiver of claim 4, said second circuit means including: discriminator means responsive to said second IF signal for generating an output signal having a level which varies relative to a threshold in one of a first and a second manner, said first manner defined by said level varying from above said threshold to below said threshold in response to said second IF signal being generated by mixing said swept oscillator signal with a received police radar signal in a first band, said second manner defined by said level varying from below said threshold to above said threshold in response to said second IF signal being generated by mixing said swept oscillator signal with a received police radar signal in a second band; and means coupled to the discriminator means for indicating that the received police signal is in (1) the first band when said level varies in said first manner and (2) the second band when said level varies in said second manner.

Claim 7

A receiver adapted to indicate from which of two bands of frequencies a signal is detected, the receiver comprising: oscillator means for generating a first swept oscillator signal and a second swept oscillator signal, said first oscillator signal swept in frequency between a first frequency and a second frequency correlated to a first band of frequencies, and said second oscillator signal swept in frequency between a third frequency and a fourth frequency correlated to a second band of frequencies; mixer means adapted to mix said first swept oscillator signal with signals in the first band and said second oscillator signal with signals in the second band for generating a primary IF signal and an image IF signal in response to receipt of a signal in either of the first and second frequency bands; filter means for passing one of said primary IF and image IF signals; discriminator means responsive to said passed IF signal for generating an output signal having a level which varies relative to a threshold (1) in a first manner from above said threshold to below said threshold in response to said passed IF signal being generated by mixing said first swept oscillator signal with a received signal in the first band and (2) in a second manner from below said threshold to above said threshold in response to said passed IF signal being generated by mixing said second swept oscillator signal with a received signal in the second band; and means coupled to the discriminator means for indicating that said received signal is in (1) the first band when said level varies in said first manner and (2) the second band when said level varies in said second manner.

Claim 8

A receiver adapted to indicate from which of two bands of frequencies a signal is detected, the receiver comprising: oscillator means for generating a first swept oscillator signal and a second swept oscillator signal, said first oscillator signal swept in frequency between a first frequency and a second frequency correlated to a first band of frequencies, and said second oscillator signal swept in frequency between a third frequency and a fourth frequency correlated to a second band of frequencies; mixer means adapted to mix said first swept oscillator signal with signals in the first band and said second oscillator signal with signals in the second band for generating a primary IF signal and an image IF signal in response to receipt of a signal in either of the first and second frequency bands; filter means for passing one of said primary IF and image IF signals; discriminator means responsive to said passed IF signal for generating an output signal having a level which varies relative to a threshold (1) in a first manner from above said threshold to below said threshold in response to said passed IF signal being generated by mixing said first swept oscillator signal with a received signal in the first band and (2) in a second manner from below said threshold to above said threshold in response to said passed IF signal being generated by mixing said second swept oscillator signal with a received signal in the second band; and means coupled to the discriminator means for indicating that said received signal is in (1) the first band when said level varies in said first manner and (2) the second band when said level varies in said second manner.

Claim 9

The receiver of claim 6, said level being a voltage level and said threshold being a threshold voltage.

Claim 10

The receiver of claim 6, further including: second oscillator means for generating a third oscillator signal at a predetermined frequency; and second mixer means for mixing said third oscillator signal with said passed IF signal to provide a further signal to said discriminator means.

Claim 11

The receiver of claim 6, said last named means including: first circuit means coupled to said discriminator means for providing evaluation signals which are alternatively in either a first state or a second state at a given time, said state being indicative of said level of said output signal relative to said threshold at said given time; and second circuit means coupled to said first circuit means for generating a first band signal indicative of receipt of a signal in the first band and a second band signal indicative of receipt of a signal in the second band, said first band signal being generated when said evaluation signals are in only said first state throughout a first time interval and are in only said second state throughout a third time interval, said third time interval beginning a second time interval after said first time interval ends, said second band signal being generated when said evaluation signals are in only said second state throughout said first time interval and are in only said first state throughout said third time interval.

Claim 12

The receiver of claim 6, said last named means including: first circuit means coupled to said discriminator means for providing evaluation signals which are alternatively in either a first state or a second state at a given time, said state being indicative of said level of said output signal relative to said threshold at said given time; second circuit means coupled to said first circuit means for generating a first status signal when said evaluation signals are in only said first state throughout a time interval and a second status signal when said evaluation signals are in only said second state throughout said time interval; and third circuit means coupled to said second circuit means for generating a first band signal indicative of receipt of a signal in the first band and a second band signal indicative of receipt of a signal in the second band, said first band signal being generated when said first status signal is generated throughout a first consecutive number of said time intervals and said second status signal is generated throughout a third consecutive number of said time intervals, said third consecutive number of said time intervals beginning a second consecutive number of said time intervals after said first consecutive number of said time intervals ends, said second band signal being generated when said second status signal is generated throughout said first consecutive number of said time intervals and said first status signal is generated throughout said third consecutive number of said time intervals.

Claim 13

The receiver of claim 10, said second circuit means comprising: first latch means coupled to said first circuit means for generating a first latch signal which is in a third state if said evaluation signals are in said first state during any portion of said time interval and which is in a fourth state if said evaluation signals are in only said second state throughout said time interval; second latch means coupled to said first circuit means for generating a second latch signal which is in a fifth state if said evaluation signals are in said second state during any portion of said time interval and which is in a sixth state if said evaluation signals are in only said first state throughout said time interval; and means coupled to the first and second latch means for generating (1) said first status signal when said first latch signal is in said third state while said second latch signal is in said sixth state, and (2) said second status signal when said first latch signal is in said fourth state while said second latch signal is in said fifth state.

Claim 14

The receiver of claim 6, said last named means including: first circuit means coupled to said discriminator means for providing evaluation signals which are alternatively in either a first state or a second state at a given time, said state being indicative of the voltage of said output signal relative to said threshold at said given time; first latch means coupled to said first circuit means for generating a first latch signal which is in a third state if said evaluation signals are in said first state during any portion of a time interval and which is in a fourth state if said evaluation signals are in said second state throughout said time interval; second latch means coupled to said first circuit means for generating a second latch signal which is in a fifth state if said evaluation signals are in said second state during any portion of said time interval and which is in a sixth state if said evaluation signals are in said first state throughout said time interval; first shift register means coupled to said first latch means for sequentially storing said state of said first latch signal during a first consecutive number of said time intervals; second shift register means coupled to said first latch means for sequentially storing said state of said first latch signal during a second consecutive number of said time intervals, said second consecutive number of said time intervals beginning a third consecutive number of said time intervals after said first consecutive number of said time intervals ends; third shift register means coupled to said second latch means for sequentially storing said state of said second latch signal during said first consecutive number of said time intervals; fourth shift register means coupled to the second latch means for sequentially storing said state of said second latch signal during said second consecutive number of said time intervals; second circuit means coupled to said first shift register means for generating a first hit signal if each said stored first latch signal state is said fourth state; third circuit means coupled to said second shift register means for generating a second hit signal if each said stored first latch signal state is said fourth state; fourth circuit means coupled to said third shift register means for generating a third hit signal if each said stored second latch signal state is said sixth state; fifth circuit means coupled to said fourth shift register means for generating a fourth hit signal if each said stored second latch signal state is said sixth state; sixth circuit means coupled to said second and fourth circuit means for indicating that the received signal is in the first band when said first hit signal and said third hit signal are both generated as said swept oscillator signals are swept in frequency; and seventh circuit means coupled to said third and fifth circuit means for indicating that the received signal is in the second band when said second hit signal and said fourth hit signal are both generated as said swept oscillator signals are swept in frequency.

Claim 19

The method of claim 14 wherein said level is a voltage level and said threshold is a threshold voltage.

Claim 20

The method of claim 14 wherein generating an indicator comprises: generating evaluation signals which are alternatively in either a first or a second state at a given time, said state being indicative of said level of said output signal relative to said threshold at said given time; generating a first band signal indicative of receipt of a signal in the first band when said evaluation signals are in only said first state throughout a first time interval and are in only said second state throughout a third time interval, said third time interval beginning a second time interval after said first time interval ends; and generating a second band signal indicative of receipt of a signal in the second band when said evaluation signals are in only said second state throughout said first time interval and in only said first state throughout said third time interval.

Claim 21

The method of claim 14 wherein generating an indicator comprises: generating evaluation signals which are alternatively in either a first or a second state at a given time, said state being indicative of said level of said output signal relative to said threshold at said given time; generating a first status signal when said evaluation signals are in only said first state throughout a time interval; generating a second status signal when said evaluation signals are in only said second state throughout said time interval; generating a first band signal indicative of receipt of a signal in the first band when said first status signal is generated throughout a first consecutive number of said time intervals and said second status signal is generated throughout a third consecutive number of said time intervals, said third consecutive number of said time intervals beginning a second consecutive number of said time intervals after said first consecutive number of said time intervals ends; and generating a second band signal indicative of receipt of a signal :n the second band when said second status signal is generated throughout said first consecutive number of said time intervals and said first status signal is generated throughout said third consecutive number of said time intervals.

Claim 22

The method of claim 17 wherein generating said status signals comprises: generating a first latch signal which is in a third state if said evaluation signals are in said first state during any portion of said time interval and which is in a fourth state if said evaluation signals are in only said second state throughout said time interval; generating a second latch signal which is in a fifth state if said evaluation signals are in said second state during any portion of said time interval and which is in a sixth state if said evaluation signals are in only said first state throughout said time interval; generating a said first status signal when said first latch signal is in said third state while said second latch signal is in said sixth state; generating a said second status signal when said first latch signal is in said fourth state while said second latch signal is in said fifth state.

Claim 23

The method of claim 14 wherein generating an indicator comprises: generating evaluation signals which are alternatively in either a first state or a second state at a given time, said state being indicative of said level of said output signal relative to said threshold at said given time; generating a first latch signal which is in a third state if said evaluation signals are in said first state during any portion of said time interval and which is in a fourth state if said evaluation signals are in only second state throughout said time interval; generating a second latch signal which is in a fifth state if said evaluation signals are in said second state during any portion of said time interval and which is in a sixth state if said evaluation signals are in only said first state throughout a said time interval; sequentially storing said state of said first latch signal during a first consecutive number of said time intervals; sequentially storing said state of said first latch signal during a second consecutive number of said time intervals, said second consecutive number of said time intervals beginning a third consecutive number of said time intervals after said first consecutive number of said time intervals ends; sequentially storing said state of said second latch signal during said first consecutive number of said time intervals; sequentially storing said state of said second latch signal during said second consecutive number of said time intervals; generating a first hit signal if each said stored first latch signal state is said fourth state during said first consecutive number of said time intervals; generating a second hit signal if each said stored first latch signal state is said fourth state during said second consecutive number of said time intervals; generating a third hit signal if each said stored second latch signal state is said sixth state during said first consecutive number of said time intervals; generating a fourth hit signal if each said stored second latch signal state is said sixth state during said second consecutive number of said time intervals; generating an indicator that the received signal is in the first band when said first hit signal and said third hit signal are both generated as said oscillator signals are swept in frequency; and generating an indicator that the received signal is in the second band when said second hit signal and said fourth hit signal are both generated as said oscillator signals are swept in frequency.