Sliding window discrete Fourier transform (SWDFT) police signal warning receiver
In one embodiment, a police activity detector is provided. The detector includes a receiver section and a warning section. The receiver section is configured to receive signals generated in the context of law enforcement activity. The warning section is configured to respond to a pulsed signal received by the receiver section and provide an alert if a received signal correlates to a law enforcement signal. The warning section also includes a sliding window discrete Fourier transform (SWDFT) module configured to receive a plurality of time series of data corresponding to sampling a received pulsed signal at a set of sample rates corresponding to a plurality of target frequencies, perform a SWDFT determination on each of the plurality of time series of data to determine a magnitude of the received signal at each of the targeted frequencies, which reveals the presence of a received pulsed signal when the magnitude is elevated, and issue an alert if the magnitude of the received signal corresponding to at least one of the targeted frequencies is greater than or equal to a predetermined threshold.
1. A police activity detector comprising:
a receiver section configured to receive signals generated in a context of law enforcement activity; and
a warning section configured to respond to a pulsed signal received by the receiver section and provide an alert if a received pulsed signal correlates to a law enforcement signal,
wherein the warning section is configured to determine presence of the received pulsed signal corresponding to at least one of a plurality of target carrier frequencies, wherein the warning section receives a plurality of time series of data corresponding to sampling the received pulsed signal at different sample rates based on the plurality of target carrier frequencies and performs a sliding window discrete Fourier transform (SWDFT) determination on each of the plurality of time series of data to determine a magnitude of the received pulsed signal at each of the target carrier frequencies, and issues an alert if the magnitude of the received pulsed signal corresponding to at least one of the target carrier frequencies is greater than or equal to a predetermined threshold.
2. The police activity detector of claim 1 , wherein the police activity detector comprises a GPS module configured to determine if a source of the pulsed signal is mobile or fixed.
3. The police activity detector of claim 2 , wherein the warning section is configured to confirm the alert if the source is fixed.
4. The police activity detector of claim 2 , wherein the warning section is configured to suppress the alert if the source is fixed.
5. The police activity detector of claim 2 , wherein the warning section is configured to confirm the alert if the source is mobile.
6. The police activity detector of claim 2 , wherein the warning section is configured to suppress the alert if the source is mobile.
7. The police activity detector of claim 1 , wherein the warning section comprises a memory, including a plurality of bytes of storage and the time series of data corresponding to a single sample rate are stored across individual bits of a plurality of bytes of the memory.
8. The police activity detector of claim 7 , wherein the memory comprises a random access memory of a processor of the police activity detector.
9. A method of detecting police activity comprising:
receiving a pulsed signal generated in a context of a law enforcement activity at a receiver section of a detector;
receiving a plurality of pulsed time series of data with pulse rates corresponding to a set of sample rates based on a plurality of target frequencies, at a warning section of the detector;
performing a SWDFT determination on each of the plurality of time series of data to determine a magnitude of the received pulsed signal at each of the targeted frequencies, wherein presence of a pulsed signal corresponding to at least one of the targeted frequencies is indicated when the magnitude of the received pulsed signal is elevated; and
issuing an alert if the magnitude of the received pulsed signal corresponding to at least one of the targeted frequencies is greater than or equal to a predetermined threshold.
10. The method of claim 9 , wherein the detector comprises a GPS module configured to determine if a source of the pulsed signal is mobile or fixed.
11. The method of claim 10 , wherein the warning section is configured to confirm the alert if the source is fixed.
12. The method of claim 10 , wherein the warning section is configured to suppress the alert if the source is fixed.
13. The method of claim 10 , wherein the warning section is configured to confirm the alert if the source is mobile.
14. The method of claim 10 , wherein the warning section is configured to suppress the alert if the source is mobile.
15. The method of claim 9 , wherein the warning section comprises a memory, including a plurality of bytes of storage and the time series of data corresponding to a single sample rate are stored across individual bits of a plurality of bytes of the memory.
16. The method of claim 15 , wherein the memory comprises a random access memory of a processor of the detector.