Detection and characterization of laser clipping within communication devices

• US 20120243865A1
• Filed: 03/23/2012
• Published: 09/27/2012
• Est. Priority Date: 03/25/2011
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Kolze, Thomas J., Currivan, Bruce J.
• Granted Patent: US 9,071,397 B2
• Time in Patent Office: Days
• US Class Current: 398/17
• CPC Class Codes: H04L 1/004 by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 2001/0096 Channel splitting in point-to-point links

Abstract

Detection and characterization of laser clipping within communication devices. Identification of one or more harmonics associated with a fundamental frequency by which signaling is effectuated within the communication system for laser clipping identification. Appropriate spectral signal analysis is made to identify the presence of characteristic(s) (e.g., energy, amplitude, phase, and/or other characteristic(s)), if any, at one or more harmonic frequencies within a received signal. Appropriate time correlation is performed to distinguish whether or not characteristic(s) associated with at one or more of these harmonic bands is a result of laser clipping or from some other source (e.g., such as other signals within a communication system that happened to reside at those respective harmonic bands). Such appropriate identified correlation between characteristic(s) corresponding to a fundamental frequency band of the communication signal and characteristic(s) corresponding to one or more harmonics (e.g., of that fundamental frequency band) indicates laser clipping.

Claims

1. An apparatus, comprising:

an input to receive a communication signal from a communication network including at least one laser implemented therein to effectuate signaling; and

a processor to;

analyze spectral content of the communication signal; and

based on historical correlation between at least one characteristic corresponding to a fundamental frequency band of the communication signal and at least one characteristic corresponding to at least one harmonic of the communication signal when the at least one characteristic corresponding to the fundamental frequency band of the communication signal detected, generate a histogram corresponding to a plurality of clipping events of the at least one laser;

based on the histogram and based on current correlation between the at least one characteristic corresponding to the fundamental frequency band of the communication signal and the at least one characteristic corresponding to the at least one harmonic of the communication signal, identify clipping of the at least one laser; and

wherein;

the processor to analyze the at least one characteristic corresponding to the at least one harmonic of the communication signal when the processor detecting the at least one characteristic corresponding to the fundamental frequency band of the communication signal for use to determine the correlation.

2. The apparatus of claim 1, wherein:

the processor to perform fast Fourier transform (FFT) processing of the communication signal to analyze the spectral content within the communication signal.

3. The apparatus of claim 1, further comprising:

at least one band pass filter (BPF), tuned to the at least one harmonic of the communication signal, to identify at least one of amplitude and phase corresponding to at least one harmonic of the communication signal for use by the processor to analyze the spectral content within the communication signal.

4. The apparatus of claim 1, wherein:

he at least one characteristic corresponding to the at least one harmonic of the communication signal corresponding to a first harmonic of the communication signal and corresponding to a second harmonic of the communication signal.

5. The apparatus of claim 1, wherein:

the apparatus being a communication device operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, a fiber-optic communication system, a mobile communication system, and a cable system.

6. An apparatus, comprising:

an input to receive a communication signal from a communication network including at least one laser implemented therein to effectuate signaling; and

a processor to;

analyze spectral content of the communication signal; and

based on correlation between at least one characteristic corresponding to a fundamental frequency band of the communication signal and at least one characteristic corresponding to at least one harmonic of the communication signal, identify clipping of the at least one laser.

7. The apparatus of claim 6, wherein:

the processor to perform fast Fourier transform (FFT) processing of the communication signal to analyze the spectral content within the communication signal.

8. The apparatus of claim 6, further comprising:

at least one band pass filter (BPF), tuned to the at least one harmonic of the communication signal, to identify at least one of amplitude and phase corresponding to at least one harmonic of the communication signal for use by the processor to analyze the spectral content within the communication signal.

9. The apparatus of claim 6, wherein:

the at least one characteristic corresponding to the at least one harmonic of the communication signal corresponding to a first harmonic of the communication signal and corresponding to a second harmonic of the communication signal.

10. The apparatus of claim 6, wherein:

the processor to analyze the at least one characteristic corresponding to the at least one harmonic of the communication signal when the processor detecting the at least one characteristic corresponding to the fundamental frequency band of the communication signal for use to determine the correlation.

11. The apparatus of claim 6, wherein:

the processor to compare energy corresponding to the at least one harmonic of the communication signal with at least one threshold when the processor detecting energy corresponding to the fundamental frequency band of the communication signal for use to determine the correlation.

12. The apparatus of claim 6, wherein:

the processor to;

generate a histogram corresponding to a plurality of clipping events of the at least one laser; and

based on the histogram and based on the correlation between the at least one characteristic corresponding to the fundamental frequency band of the communication signal and the at least one characteristic corresponding to the at least one harmonic of the communication signal, identify the clipping of the at least one laser.

13. The apparatus of claim 6, wherein:

the apparatus being a communication device operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, a fiber-optic communication system, a mobile communication system, and a cable system.

14. A method for operating a communication device, the method comprising:

via an input of the communication device, receiving a communication signal from a communication network including at least one laser implemented therein to effectuate signaling;

analyzing spectral content of the communication signal; and

based on correlation between at least one characteristic corresponding to a fundamental frequency band of the communication signal and at least one characteristic corresponding to at least one harmonic of the communication signal, identifying clipping of the at least one laser.

15. The method of claim 14, further comprising:

performing fast Fourier transform (FFT) processing of the communication signal to analyze the spectral content within the communication signal.

16. The method of claim 14, further comprising:

employing at least one band pass filter (BPF), tuned to the at least one harmonic of the communication signal, to identify at least one of amplitude and phase corresponding to at least one harmonic of the communication signal for use in analyzing the spectral content within the communication signal.

17. The method of claim 14, wherein:

the at least one characteristic corresponding to the at least one harmonic of the communication signal corresponding to a first harmonic of the communication signal and corresponding to a second harmonic of the communication signal.

18. The method of claim 14, further comprising:

comparing energy corresponding to the at least one harmonic of the communication signal with at least one threshold, when energy corresponding to the fundamental frequency band of the communication signal detected, for use to determine the correlation.

19. The method of claim 14, further comprising:

generating a histogram corresponding to a plurality of clipping events of the at least one laser; and

based on the histogram and based on the correlation between the at least one characteristic corresponding to the fundamental frequency band of the communication signal and the at least one characteristic corresponding to the at least one harmonic of the communication signal, identifying the clipping of the at least one laser.

20. The method of claim 14, wherein:

the communication device operative within at least one of a satellite communication system, a wireless communication system, a wired communication system, a fiber-optic communication system, a mobile communication system, and a cable system.