SHIELDING INTEGRITY TESTING FOR CABLE DROP

• US 20130110466A1
• Filed: 10/27/2011
• Published: 05/02/2013
• Est. Priority Date: 10/27/2011
• Status: Active Grant

• Current Assignee: ComSonics, Inc.
• Original Assignee: ComSonics, Inc.
• Inventors: Zimmerman, Dennis A., Comeau, Marc-Yvon, Early, Joseph R.
• Granted Patent: US 9,091,712 B2
• Time in Patent Office: Days
• US Class Current: 702/189
• CPC Class Codes: G01R 29/0835 Testing shielding, e.g. for efficiency
• CPC Class Codes: H04B 17/102 Power radiated at antenna
• CPC Class Codes: H04B 17/27 for locating or positioning the transmitter
• CPC Class Codes: H04B 17/318 Received signal strength

Abstract

Signal ingress at an installations site forming a part of a broadband communication system is quantitatively evaluated for resistance to signal ingress using a computed ambient broadcast signal level based on a known location and effective radiated power of one or more transmitters. Anomalies due to signal path obstruction and/or multi-path reception are compensated by performing computations for a plurality of broadcast transmitters located in different directions from the installation site.

Claims

1. A testing instrument for quantitatively measuring shielding integrity in a subscriber installation comprising

a tunable signal detector that can be tuned to a frequency of an over-the-air broadcast signal,

a global positioning system receiver, and

a data processor that is programmed to provide a computation of a signal power level of said over-the-air signal at a location of said testing instrument based on a location of a transmitter of known effective radiated power of said over-the-air broadcast signal.

2. The testing instrument as recited in claim 1, wherein said testing instrument comprises a spectrum analyzer.

3. The testing instrument as recited in claim 1, wherein said testing instrument comprises a signal strength meter.

4. The testing instrument as recited in claim 1, wherein said programmed data processor controls tuning of said tunable signal detector.

5. The testing instrument as recited in claim 4, wherein said tunable signal detector is tuned to a sequence of broadcast signal frequencies, each of said broadcast signal frequencies being separated from another broadcast signal frequency by a frequency interval.

6. The testing instrument as recited in claim 5, wherein said broadcast signal frequencies are FM band broadcast frequencies.

7. The testing instrument as recited in claim 1, wherein said tunable signal detector is tuned to a sequence of broadcast signal frequencies, each of said broadcast signal frequencies being separated from another broadcast signal frequency by a frequency interval.

8. The testing instrument as recited in claim 7, wherein said broadcast signal frequencies are FM band broadcast frequencies.

9. The testing instrument as recited in claim 1, further including

a GPS receiver for determining said location of said testing instrument.

10. A testing instrument as recited in claim 1, wherein said programmed data processor provides sorting of signals detected by said tunable signal detector based on signal strength received from an installation site of a broadband communication system.

18. The testing instrument as recited in claim 1, wherein said data processor computes said signal power level at said over-the-air signal at said location of said testing instrument from said location of said transmitter and said effective radiated power.

19. The testing instrument as recited in claim 1, wherein said data processor is programmed to include compensation for signal path obstruction and multi-path effects on said over-the air signal.

11. A method of measuring resistance to signal ingress in an installation site of a broadband communication system, said method including steps of

detecting a received signal level of a signal in said installation site having a frequency which corresponds to a broadcast signal frequency while said installation site is disconnected from said broadband communication system,

computing an over-the-air signal level at said broadcast frequency based on a distance from a broadcast transmitter of known effective radiated power, and

comparing signal levels determined in said detecting and computing steps to determine a resistance to signal ingress in said installation site of said broadband communication system.

12. The method as recited in claim 11, wherein said broadcast frequency is an FM broadcast signal frequency.

13. The method as recited in claim 11, including the further step of

storing locations and effective radiated power of a plurality of radio frequency transmitters in a testing instrument capable of performing said detecting step.

14. The method as recited in claim 11, including a further step of matching a plurality of signals detected in said detecting step with frequencies of transmitters local to said installation site.

15. The method as recited in claim 14, including the further step of

sorting signals detected in said detecting step by received signal strength.

16. The method as recited in claim 15, wherein an over-the-air signal strength is computed for a maximum of two transmitters in each quadrant around said installation site.

17. The method as recited in claim 11, including the further step of

determining a location of said installation site using a GPS receiver.

20. The method as recited in claim 11, wherein said computing step is further based on said effective radiated power of said transmitter.

21. The method as recited in claim 11, wherein said computing step includes compensation for signal path obstruction and multi-path effects on said over-the air signal.