Apparatus and method for characterizing the loading pattern of a telecommunications transmission line

• US 6,263,047 B1
• Filed: 09/07/1999
• Issued: 07/17/2001
• Est. Priority Date: 09/07/1999
• Status: Expired due to Term

• Current Assignee: Focus Strategies Capital Advisors LLC
• Original Assignee: Tempo Research Corp. (Textron Inc)
• Inventors: Larrick, Ronald J., Kochan, Phillip F., Randle, William C.
• Primary Examiner(s): Woo, Stella
• Assistant Examiner(s): Taylor, Barry W
• Application Number:
  US09/392,669
• Time in Patent Office: 679 Days
• Field of Search: 379/6, 379/22, 379/24, 379/26, 379/27, 379/29, 379/30, 379/31, 324/522, 324/523, 324/533
• US Class Current: 379/31
• CPC Class Codes: H04M 3/08 Indicating faults in circuits or apparatus
• CPC Class Codes: H04M 3/28 Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor

Abstract

An apparatus and method for characterizing a loading pattern of a twisted pair telecommunications transmission line includes a variable frequency signal generator and a measurement receiver connected to the twisted pair line. The signal generator applies a variable frequency signal to the twisted pair line and the measurement receiver acquires magnitude values representative of the impedance of the twisted pair line. A controller, operating under program control, models a plurality of baseline transmission line and twisted pair lines to generate magnitude values representative of the models. Error values are generated between the acquired magnitude values and the modeled magnitude values. The error values are compared to each other to determine the model with the minimum error value which is used as the model for charactering the twisted pair transmission line.

Claims

1. An apparatus for characterizing the loading pattern of a telecommunications transmission line comprising:

a signal generator producing a variable frequency output signal coupled to the telecommunications transmission line;

a measurement receiver coupled to the telecommunications transmission line that acquires magnitude values representative of the impedance of the telecommunications transmission line as a function of the signal generator output frequency;

means for modeling a plurality of telecommunications transmission lines to generate magnitude values representative of the impedance of the modeled telecommunications transmission lines as a function of frequency;

means for calculating an error value for each of the modeled telecommunications transmission lines by comparing the acquired magnitude values with the modeled magnitude values; and

means for comparing the error values of the modeled telecommunications transmission lines to each other to determine the modeled telecommunications transmission line with the minimum error value that characterizes the loading pattern of the measured telecommunications transmission line.

2. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claims 1 wherein the modeling means, the calculating means and the comparing means further comprise a controller executing instructions stored in a memory device.

3. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claims 2 wherein the memory device contains coefficients of two-port transmission line networks representing segments of the telecommunications transmission line.

4. An apparatus for characterizing the loading pattern of a telecommunications transmission line comprising:

a signal generator producing a variable frequency output signal having a magnitude value coupled to the telecommunications transmission line;

a measurement receiver coupled to the telecommunications transmission line that acquires magnitude values representative of the impedance of the telecommunications transmission line as a function of the signal generator output frequency;

means for normalizing the acquired magnitude values by the magnitude value of the variable frequency output signal;

means for modeling a plurality of telecommunications transmission lines and a plurality of baseline telecommunications transmission lines to generate magnitude values representative of the impedance of the modeled and baseline telecommunications transmission lines as a function of frequency;

means for calculating an error value for each of the modeled and baseline telecommunications transmission lines by comparing the acquired magnitude values with the modeled and baseline magnitude values;

means for estimating a wire gauge for the telecommunications transmission line using the baseline telecommunications transmission lines having the minimum error value;

means for estimating a first missing load coil in the telecommunications transmission line by modeling baseline transmission lines with a missing load coil at various locations in the baseline transmission line at the estimated wire gauge and using the modeled baseline transmission line with the minimum error value;

means for estimating additional missing load coils in the telecommunications transmission line using the modeled telecommunications transmission lines at the estimated wire gauge and the estimated location of the first missing load coil; and

means for comparing the error values of the modeled telecommunications transmission lines with the estimated additional missing load coils to each other to determine the modeled telecommunications transmission line with the minimum error value that characterizes the loading pattern of the measured telecommunications transmission line.

5. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claims 4 wherein the calculating means generates an RMS error value for each of the modeled and baseline telecommunications transmission lines using ratio values derived from the acquired magnitude values divided by the magnitude values of the respective modeled and baseline telecommunications transmission lines at common frequency values.

6. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claims 5 further comprising an additional comparing means that compares the ratio values of the respectively modeled baseline telecommunications transmission lines to a threshold value to select modeled baseline telecommunications transmission lines that may characterize the loading pattern of the measured telecommunications transmission line.

7. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claims 4 wherein the calculating means generates an average difference error value for each of the modeled and baseline telecommunications transmission lines using difference values derived by the difference between the acquired magnitude values and the magnitude values of the modeled and the baseline telecommunications transmission lines at common frequency values.

8. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claims 4 further comprising an additional comparing means that compares the difference values of the respectively modeled telecommunications transmission lines to a threshold value to select modeled telecommunications transmission lines that may characterize the loading pattern of the measured telecommunications transmission line.

9. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claims 4 wherein the normalizing means, the modeling means, the calculating means, the various estimating means and the comparing means further comprise a controller executing instructions stored in a memory device.

10. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claims 4 wherein the memory device contains coefficients of a plurality of two-port transmission line network models at selected frequencies and wire gauges representing segments of the telecommunications transmission line and baseline telecommunications transmission lines.

11. The apparatus for characterizing the loading pattern of a telecommunications transmission line as recited in claim 10 wherein the coefficients of the plurality of two-port transmission line networks representing the baseline telecommunications transmission lines models at various wire gauges have a plurality of load coils with the plurality of load coils being in the range of thirty-six load coils.

14. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 11 wherein the modeling step comprises the steps of:

a) concatenating multiple two-port transmission line model segments to generate coefficients that model a plurality of sections of the telecommunications transmission line;

b) concatenating multiple two-port transmission line model sections to generate coefficients that model a plurality of telecommunication transmission lines;

c) generating impedance values as a function of frequency using the plurality of two port transmission line network models; and

d) generating magnitude values representative of the impedance of the modeled telecommunications transmission lines as a function of the generated impedance values.

12. A method of characterizing the loading pattern of a telecommunications transmission line comprising the steps of:

a) applying a variable frequency signal to the telecommunications transmission line;

b) acquiring magnitude values representative of the impedance of the telecommunications transmission line as a function of the variable frequency signal;

c) modeling a plurality of telecommunications transmission lines to generate magnitude values representative of the impedance of the modeled telecommunications transmission lines as a function of frequency;

d) calculating an error value for each of the modeled telecommunications transmission lines by comparing the acquired magnitude values with the modeled magnitude values; and

e) comparing the error values of the modeled telecommunications transmission lines to each other to determine the modeled telecommunications transmission line with the minimum error value that characterizes the loading pattern of the measured telecommunications transmission line.

13. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 12 wherein an initial step comprises storing coefficients of a plurality of two-port transmission line network models at selected frequencies and transmission line wire gauges that represents segments of the telecommunications transmission.

15. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 12 wherein an initial step comprises storing coefficients of two-port transmission line network models at selected frequencies and transmission line wire gauges that represents sections of the telecommunications transmission line.

16. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 15 wherein the modeling step comprises the steps of:

a) concatenating multiple two-port transmission line model sections to generate coefficients that model a plurality of telecommunication transmission lines;

b) generating impedance values as a function of frequency using the plurality of two port transmission line network models; and

c) generating magnitude values representative of the impedance of the modeled telecommunications transmission lines as a function of the generated impedance values.

17. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 16 wherein the variable frequency signal has a magnitude and the acquiring magnitude value step further comprises the step of normalizing the acquired magnitude values as a function of the magnitude of the variable frequency signal.

18. A method of characterizing the loading pattern of a telecommunications transmission line comprising the steps of:

a) applying a variable frequency signal having a magnitude value to the telecommunications transmission line;

b) acquiring magnitude values representative of the impedance of the telecommunications transmission line as a function of the variable frequency signal;

c) normalizing the acquired magnitude values as a function of the magnitude of the variable frequency signal;

d) modeling a plurality of baseline telecommunications transmission lines to generate magnitude values representative of the impedance of the baseline telecommunications transmission lines as a function of frequency;

e) calculating an error value for each of the baseline telecommunications transmission lines by comparing the acquired magnitude values with the baseline magnitude values;

f) estimating a wire gauge for the telecommunications transmission line using the baseline telecommunications transmission line having the minimum error value;

g) estimating a first missing load coil in the telecommunications transmission line by modeling baseline transmission lines with a missing load coil at various locations in the baseline telecommunications transmission line at the estimated wire and using the baseline missing load coil transmission line model with the minimum error value;

h) modeling a plurality of telecommunications transmission lines using the estimated wire gauge and the estimated location of the first missing load coil to generate magnitude values representative of the impedance of the modeled telecommunications transmission lines as a function of frequency;

i) estimating the wire gauge by calculating a difference value between a first local minimum magnitude value in the acquired magnitude values and the corresponding magnitude value for each of the modeled telecommunications transmission lines and using the modeled telecommunications transmission line with the minimum difference value;

j) estimating additional missing load coils in the telecommunications transmission line using the modeled telecommunications transmission lines at the estimated wire gauge and the estimated location of the first missing load coil to generate amplitude and frequency error values; and

k) comparing the error values of the modeled telecommunications transmission lines with the estimated additional missing load coils to each other to determine the modeled telecommunications transmission line with the minimum error value that characterizes the loading pattern of the measured telecommunications transmission line.

19. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 18 wherein an initial step comprises storing coefficients of a plurality of two-port transmission line network models at selected frequencies and transmission line wire gauges that represents baseline telecommunications transmission lines and segments of the telecommunications transmission line.

20. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 19 wherein the modeling step further comprises initial steps of:

a) estimating a beginning length for the transmission line as a function of the acquired magnitude value at a moderately high acquired frequency; and

b) estimating a length for the transmission line as a function of the acquired magnitude value at the lowest acquired frequency.

21. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 20 further comprising the step of estimating a load coil count for the transmission line that represents the estimated number of load coils in the transmission line using the estimated length of the transmission line.

22. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 21 wherein the baseline transmission line modeling step further comprises the steps of:

a) generating impedance values as a function of frequency using the plurality of two port transmission line network models; and

b) generating magnitude values representative of the impedance of the baseline telecommunications transmission lines as a function of the generated impedance values.

23. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 22 wherein the baseline transmission line error value calculating step further comprises the steps of:

a) calculating deviation values between the acquired magnitude values and the baseline magnitude values for each of the modeled baseline telecommunications transmission lines;

b) comparing the deviation values to a threshold value to select modeled baseline telecommunications transmission lines that may represent a correct wire gauge for the telecommunications transmission line;

c) generating an RMS error value for each of the selected modeled baseline telecommunications transmission lines using averaged normalized ratio values derived from the acquired magnitude values divided by the magnitude values of the respective modeled baseline telecommunications transmission lines at common frequency values.

24. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 23 wherein the deviation value calculating step further comprises the step of normalizing the acquired magnitude values by the magnitude values of the respective modeled baseline telecommunications transmission lines at common frequency values.

25. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 23 wherein the deviation value calculating step further comprises the step of determining the difference between the acquired magnitude values and the magnitude values of the respective modeled baseline telecommunications transmission lines at common frequency values.

26. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 23 wherein the first missing load coil estimating step further comprises the steps of:

a) establishing load coil parameters for the first missing load coil position using the respective beginning length of the telecommunications transmission line and the load coil count;

b) calculating deviation values between the acquired magnitude values and the baseline magnitude values for each of the modeled baseline missing load coil telecommunications transmission lines within the load coil parameters;

b) comparing the deviation values to a threshold value to select modeled baseline missing load coil telecommunications transmission lines that may represent the correct location of the missing load coil;

c) generating an RMS error value for each of the selected modeled baseline missing load coil telecommunications transmission lines using averaged normalized ratio values derived from the acquired magnitude values divided by the magnitude values of the respective modeled baseline missing load coil telecommunications transmission lines at common frequency values; and

d) selecting the modeled baseline missing load coil telecommunications transmission line model with the minimum RMS error as representing the location of the first missing load coil.

27. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 26 wherein the first missing load coil estimating step further comprises the steps of:

a) calculating deviation values between the acquired magnitude values and the baseline magnitude values for each of the modeled baseline missing load coil telecommunications transmission lines at various wire gauges;

b) comparing the deviation values to a threshold value to select the modeled baseline missing load coil telecommunications transmission lines that may represent the correct wire gauge;

c) generating an RMS error value for each of the selected modeled baseline missing load coil telecommunications transmission lines using averaged normalized ratio values derived from the acquired magnitude values divided by the magnitude values of the respective modeled baseline missing load coil telecommunications transmission lines at common frequency values; and

d) selecting the modeled baseline missing load coil telecommunications transmission line model with the minimum RMS error as having the correct wire gauge.

28. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 27 wherein the telecommunications transmission line modeling step further comprises the steps of:

a) concatenating multiple two-port transmission line model segments to generate coefficients that model a plurality of sections of the telecommunications transmission line;

b) concatenating multiple two-port transmission line model sections to generate coefficients that model a plurality of telecommunication transmission lines;

c) generating impedance values as a function of frequency using the plurality of two port transmission line network models; and

d) generating magnitude values representative of the impedance of the modeled telecommunications transmission lines as a function of the generated impedance values.

29. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 28 wherein the estimating wire gauge step further comprises the steps of:

a) determining a frequency of a local minimum value in the acquired magnitude values;

b) calculating deviation values between the acquired magnitude value at the local minimum frequency and the corresponding magnitude value for each of the modeled telecommunications transmission lines at the various gauges;

d) generating an RMS amplitude error value for each of the modeled telecommunications transmission lines using averaged normalized ratio values derived from the acquired magnitude values divided by the magnitude values of the respective modeled telecommunications transmission lines at common frequency values; and

f) selecting the modeled telecommunications transmission line model with the minimum first local minimum deviation values and RMS amplitude error values as having the correct wire gauge.

30. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 29 wherein the estimating additional missing load coil step further comprises the steps of:

a) determining frequencies of local minimum and maximum magnitude value in the acquired magnitude values;

b) calculating deviation values between the magnitude values in the acquired magnitude values at the local minimum and maximum frequencies and the corresponding magnitude value for each of the modeled telecommunications transmission lines;

c) comparing the deviation values to a threshold value to select the modeled telecommunications transmission lines that may represent the correct modeled transmission line with additional missing load coils;

d) generating an RMS amplitude error value for each of the modeled telecommunications transmission lines using averaged normalized ratio values derived from the acquired magnitude values divided by the magnitude values of the respective modeled telecommunications transmission lines at common frequency values;

e) generating an RMS frequency error value for each of the modeled telecommunications transmission lines using averaged normalized ratio values derived from the frequency difference between the local minimum and maximum acquired magnitude values and corresponding minimum and maximum magnitude values of the modeled telecommunications transmission lines; and

f) comparing the first local minimum deviation values, RMS amplitude and RMS frequency error values of the modeled telecommunications transmission lines with the estimated additional load coil to each other to determine the modeled telecommunications transmission line with the minimum first local minimum difference value, RMS amplitude and RMS frequency value that characterizes the loading pattern of the measured telecommunications transmission line.

31. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 30 wherein the deviation value calculating step further comprises the step of normalizing the local minimum and maximum acquired magnitude values by the corresponding magnitude values of the respective modeled telecommunications transmission lines at common frequency values.

32. The method of characterizing the loading pattern of a telecommunications transmission line as recited in claim 30 wherein the deviation value calculating step further comprises the step of determining the difference between the local minimum and maximum acquired magnitude values and the corresponding magnitude values of the respective modeled telecommunications transmission lines at common frequency values.