Advanced parameter encoder with dual integrated pulse present detection and channel/sector arbitration

• US 5,550,546 A
• Filed: 05/03/1995
• Issued: 08/27/1996
• Est. Priority Date: 11/19/1993
• Status: Expired due to Term

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: TRW Inc. (Northrop Grumman Corporation)
• Inventors: Porter, Donald A., Noneman, Mark E.
• Primary Examiner(s): Pihulic, Daniel T.
• Application Number:
  US08/433,174
• Time in Patent Office: 482 Days
• Field of Search: 342/13, 342/20
• US Class Current: 342/13
• CPC Class Codes: G01S 7/021 Auxiliary means for detecting or identifying radar signals or the like, e.g. radar jamming signals

Abstract

In a channelized receiver there is dual pulse present detection in which an RF signal is converted to a digital word and there are dual digital thresholds, each digital threshold having a programmable standard for determining when a pulse is present after said pulse has exceeded the particular threshold value and for determining which pulse will be reported based on which pulse arrived first. The invention also involves arbitration between adjacent channels in a channelized receiver to determine which signals are real and which signals represent spill-over energy from signals in adjacent channels and also including arbitration between spatial sectors to determine which signals are real and which signal represents spill-over energy from adjacent sectors.

Claims

1. A pulse present detection system comprising:

receiver means for receiving an RF signal and amplifier means for amplifying said RF signal;

converter means connected to said amplifier means for converting said received RF signal to digital words representing the instantaneous amplitude over selected periodic time increments of said RF signal,

detector means having multiple threshold levels in which the digital value of said sampled RF signal is compared to the threshold values,

each threshold value having a separate and programmable number of amplitude samples that must occur above said threshold before a pulse presence is declared,

each threshold level having a separate reporting means for reporting a separate pulse presence signal, and

resolution means for selecting between pulse present signals reported by said threshold levels wherein the first threshold level to report a pulse present is selected.

3. The pulse present detection system of claim 1 including:

hysteresis means associated with each threshold means for lowering said threshold value by a preprogrammed amount when a pulse presence is detected for that threshold.

4. The pulse present detection system of claim 1 including:

hysteresis means associated with each threshold means for lowering said threshold value by a preprogrammed amount when a pulse presence is detected for that threshold.

5. The pulse present detection system of claim 1 wherein said digital samples are taken at a predetermined time interval from between 20 nanoseconds and 100 nanoseconds.

2. A pulse present detection system comprising:

receiver means for receiving an RF signal and amplifier means for amplifying said RF signal,

converter means connected to said amplifier means for converting said received RF signal to digital words representing the instantaneous amplitude over selected periodic time increments of said RF signal, and

detector means for detecting high amplitude, short duration pulses and low amplitude, long duration pulses, said detector means having multiple threshold levels in which the digital value of said sampled RF signal is compared to the threshold values, a first of the threshold levels being higher in amplitude than a second of the threshold levels, said detector means identifying a pulse presence signal upon the occurrence of either of the following events;

1) when X samples are above the first threshold level;

or

2) when Y samples are above the second threshold level, wherein both X and Y are integers and are separately programmable, both the first and second threshold levels also are separately programmable, and wherein Y is greater than X so that the first threshold level detects said high amplitude short duration pulses and the second threshold level detects said low amplitude long duration pulses.

6. A system for arbitrating between RF signals in adjacent frequency bands comprising:

receiver means for receiving an RF signal,

amplifier means connected to said receiver means for amplifying said received RF signal,

converter means for converting said amplified RF signal to digital words, said conversions taking place instantaneously on a periodic basis,

arbitration means having a present and a past integration register, said arbitration means having programmable arbitration events, said arbitration events being the initial presence of a pulse and loss of stable, said arbitration means further having means for indicating the end of a signal,

second amplifier means connected to said receiver means for amplifying said received RF signal,

second converter means for converting said amplified RF signal to digital words, said conversions taking place instantaneously on a periodic basis,

second arbitration means having a second present and a second past integration register, said arbitration means having programmable arbitration events, said arbitration events being the initial presence of a pulse and loss of stable, said arbitration means further having means for indicating the end of a signal,

said arbitration means integrating a predetermined number of amplitude samples at the beginning of a pulse and storing said amplitude samples in said present integration register, said arbitration means establishing a coincident window wherein if a pulse in said second arbitration means arrives within said coincidence window, said second arbitration means integrates a predetermined number of amplitude samples of said pulse and stores said integrated value in said second present integration register of said second arbitration means, said first arbitration means comparing the contents of said present integration register to the larger of the contents of said second past and present integration registers.

7. The system of claim 6 wherein:

said arbitration means further storing amplitude samples upon loss of stable and establishing a coincidence window at loss of stable for comparison to a signal in said second arbitration means occurring during said coincidence window and transferring the contents of said present integration register to said past integration register and comparing the larger of the contents of said second past and present integration register to the contents of said first present integration register to determine which signal will be reported.

8. The system of claim 6 wherein:

said amplifier means convert said received RF signal to a log video signal.

9. The system of claim 6 wherein:

the coincidence window established by said arbitration means is programmable in width.

10. The system of claim 7 wherein:

the coincidence windows established by said arbitration means are programmable in width.

11. A system for arbitrating between RF signals in adjacent frequency bands comprising:

receiver means for receiving an RF signal,

amplifier means connected to said receiver means for amplifying said received RF signal,

converter means for converting said amplified RF signal to digital words, said conversions taking place instantaneously on a periodic basis,

arbitration means having a present and a past integration register, said arbitration means having programmable arbitration events, said arbitration events being the initial presence of a pulse and loss of stable, said arbitration means further having means for indicating the end of a signal,

second amplifier means connected to said receiver means for amplifying said received RF signal,

second converter means for converting said amplified RF signal to digital words, said conversions taking place instantaneously on a periodic basis,

second arbitration means having second present and a second past integration register, said arbitration means having programmable arbitration events, said arbitration events being the initial presence of a pulse and loss of stable, arbitration means further having means for indicating the end of a signal,

said arbitration means integrating a predetermined number of amplitude samples at the end of a pulse and storing said amplitude samples in said present integration register, said arbitration means establishing a coincident window wherein if a pulse in said second arbitration means arrives within said coincidence window, said second arbitration means integrates a predetermined number of amplitude samples of said pulse and stores said integrated value in said second present integration register of said second arbitration means, said first arbitration means comparing the contents of said present integration register with the contents of second integration register.

12. A radio frequency (RF) receiver system comprising:

a plurality of antennas, each antenna covering a separate but adjacent sector in space;

amplifier means connected to each of the antennas;

detector means, coupled to the amplifiers, for sensing when RF signals are received by multiple antennas within a given coincidence window of time; and

arbitration means for selecting the RF signal detected by only one of the antennas by comparing the strengths of the signals received by the antennas within the coincidence window and choosing the signal having the greatest power.

13. The system of claim 12 wherein the time of the coincidence window is programmable.

14. The system of claim 12 wherein said arbitration means is preprogrammed to select a predetermined single antenna signal in the event that plural signals have substantially the same power.

15. A system for arbitrating between RF signals in adjacent frequency bands comprising:

a receiver having a plurality of channels having adjacent frequency bands, each frequency band having an amplifier providing an output signal;

threshold means for determining when the output signals from a plurality of amplifiers exceed a given threshold level within a programmable coincidence window of time; and

arbitration means for selecting the output signal from the amplifier having the greatest power and rejecting signals from the other amplifiers thereby eliminating energy spill-over from channels adjacent to the channel associated with the proper frequency of the received signal.