Frequency domain bitmap triggering using color, density and correlation based triggers

• US 8,489,350 B2
• Filed: 09/28/2009
• Issued: 07/16/2013
• Est. Priority Date: 03/13/2009
• Status: Active Grant

• Current Assignee: Tektronix Incorporated (Fortive Corp.)
• Original Assignee: Tektronix Incorporated (Fortive Corp.)
• Inventors: Engholm, Kathryn A., Gee, Edward C., Hillman, Alfred K. Jr., Eby, David
• Primary Examiner(s): COSIMANO, EDWARD R
• Application Number:
  US12/568,141
• Publication Number:
  US 20100231398A1
• Time in Patent Office: 1,387 Days
• Field of Search: 734/321, 738/658, 324/76.11, 324/76.12, 324/76.13, 324/76.16, 346/45, 346/46, 377/1, 377/13, 702/1, 702/57, 702/66, 702/127, 702/128, 702/179, 702/180, 702/187, 702/189, 708/100, 708/105, 708/200, 708/212, 715/200, 715/273, 715/275
• US Class Current: 702/66
• CPC Class Codes: G01R 13/0263 for non-recurrent functions, e.g. transients
• CPC Class Codes: G01R 23/16 Spectrum analysis; Fourier analysis

Abstract

An RF test and measurement device, including a front end for receiving a time-varying signal and a real-time engine for generating digital frequency domain spectrums based on the time-varying signal. The device also includes a memory subsystem containing a frequency domain bitmap which is updated through sequential receipt and storage of the digital frequency domain spectrums. The real time engine is further configured to monitor the frequency domain bitmap for occurrence of a signal characteristic, and in response to detection of the signal characteristic, cause a capture of the time-varying signal into a storage location of the RF test and measurement device.

Claims

1. A method for triggering upon signal events in an RF test and measurement device, comprising:

repeatedly sampling a time-varying signal;

generating, over time, a plurality of digital frequency domain spectrums based on the sampling of the time-varying signal;

repeatedly updating a frequency domain bitmap for the time-varying signal by sequentially applying the digital frequency domain spectrums to a data store containing the frequency domain bitmap; and

triggering a capture of the time-varying signal in response to detection of an occurrence of a pre-defined characteristic in the frequency domain bitmap.

2. The method of claim 1, where triggering a capture of the time-varying signal includes:

specifying a region of interest on the frequency domain bitmap;

establishing a trigger criteria based on a color or intensity characteristic of a display device rendering of data from the region of interest; and

performing the capture of the time-varying signal upon satisfaction of the trigger criteria.

3. The method of claim 1, where triggering a capture of the time-varying signal includes

specifying a region of interest on the frequency domain bitmap;

establishing a trigger criteria based on a density characteristic of a display device rendering of data from the region of interest; and

performing the capture of the time-varying signal upon satisfaction of the trigger criteria.

4. The method of claim 1, where triggering a capture of the time-varying signal includes

specifying a region of interest on the frequency domain bitmap;

establishing a trigger criteria based on a bitmap hit count for the region of interest; and

performing the capture of the time-varying signal upon satisfaction of the trigger criteria.

5. The method of claim 1, where triggering a capture of the time-varying signal includes

specifying a region of interest on the frequency domain bitmap;

specifying a reference in the region of interest;

establishing a trigger criteria based on a degree of correlation between collected spectral data and the reference; and

performing the capture of the time-varying signal when collected spectral data meets or exceeds a threshold degree of correlation to the reference.

6. The method of claim 1, further comprising periodically sampling the frequency domain bitmap and using said sampling to provide a spectrum display on a display device.

7. The method of claim 6, further comprising receiving a user input in reference to the spectrum display to establish the selected portion of the frequency domain bitmap.

8. The method of claim 1, where the frequency domain bitmap is a two-dimensional grid with cells having specified frequency/power values for frequency and power, and where repeatedly updating the frequency domain bitmap includes, for each one of the digital frequency domain spectrums, incrementing specific cells of the frequency domain bitmap if corresponding values are present in said one of the digital frequency domain spectrums.

9. The method of claim 8, where triggering a capture of the time-varying signal in response to detection of an occurrence of a predefined characteristic in the frequency domain bitmap includes determining, for a selected portion of the frequency domain bitmap, whether a spectrum waveform prevalence of the digital frequency domain spectrums exceeds a threshold in such selected portion.

10. The method of claim 8, further comprising periodically sampling the frequency domain bitmap and using said sampling to provide a spectrum display.

11. The method of claim 10, where the spectrum display is configured so that coloration of individual cells in the spectrum display is dependent upon a prevalence of corresponding frequency/power values present in the digital frequency domain spectrums applied to the data store containing the frequency domain bitmap.

12. The method of claim 11, where the predefined characteristic is expressed in terms of the coloration of individual cells on the spectrum display.

13. The method of claim 12, where the spectrum display is configured so that intensity of individual cells in the spectrum display is dependent upon a prevalence of corresponding frequency/power values present in the digital frequency domain spectrums applied to the data store containing the frequency domain bitmap.

14. An RF test and measurement device, comprising:

a front end section for receiving a time-varying signal;

a real-time engine operatively coupled with the front end section and configured to generate digital frequency domain spectrums based on the time-varying signal as the time-varying signal is received and processed through the front end section; and

a memory subsystem containing a frequency domain bitmap which is updated through sequential receipt and storage of the digital frequency domain spectrums,

where the real time engine is further configured to monitor the frequency domain bitmap for occurrence of a signal characteristic, and in response to detection of the signal characteristic, cause a capture of the time-varying signal into a storage location of the RF test and measurement device.

15. The device of claim 14, further comprising a user interface configured to receive user inputs that yield specification of a region of interest on the frequency domain bitmap, and specification of the signal characteristic in terms of a color-based characteristic of the frequency domain bitmap, where the color-based characteristic pertains to coloration of the region of interest of the frequency domain bitmap when the frequency domain bitmap is rendered for display on a display device of the RF test and measurement device.

16. The device of claim 14, further comprising a user interface configured to receive user inputs that yield specification of a region of interest on the frequency domain bitmap, and specification of the signal characteristic in terms of a density-based characteristic of the frequency domain bitmap, where the density-based characteristic is an occupancy rate within the region of interest of the frequency domain bitmap.

17. The device of claim 14, further comprising a user interface configured to receive user inputs that yield specification of a region of interest on the frequency domain bitmap, and specification of the signal characteristic in terms of a degree of correlation between spectral data collected for the region of interest and a reference.

18. The device of claim 17, where the reference is externally supplied.

19. The device of claim 17, where the reference is generated based on internal data acquired from the frequency domain bitmap.

20. A method for triggering upon signal events in an RF test and measurement device, comprising:

establishing a region of interest on a frequency domain bitmap which is configured to store digitized power data as a function of frequency;

specifying triggering criteria for the region of interest in terms of a predefined characteristic;

repeatedly sampling a time-varying signal;

generating, over time, a plurality of digital frequency domain spectrums based on the sampling of the time-varying signal;

repeatedly updating the frequency domain bitmap by sequentially applying the digital frequency domain spectrums to a data store containing the frequency domain bitmap; and

triggering a capture of the time-varying signal in response to detection of the pre-defined characteristic in the region of interest of the frequency domain bitmap.

21. The method of claim 20, where specifying triggering criteria for the region of interest in terms of a predefined characteristic includes specifying coloration of the region of interest when the region of interest is rendered upon a display device of the RF test and measurement device.

22. The method of claim 20, where specifying triggering criteria for the region of interest in terms of a predefined characteristic includes specifying an occupancy rate in the region of interest when the region of interest is rendered upon a display device of the RF test and measurement device.

23. The method of claim 20, where specifying triggering criteria for the region of interest in terms of a predefined characteristic includes specifying a correlation threshold, where the correlation threshold indicates a degree of correlation existing between a reference and spectral data in the region of interest.