System and method for resistance measurement

• US 7,429,866 B2
• Filed: 08/21/2006
• Issued: 09/30/2008
• Est. Priority Date: 08/21/2006
• Status: Expired due to Fees

• Current Assignee: Avo Multi-AMP Corporation (Thyssen Bornemisza Family)
• Original Assignee: Avo Multi-AMP Corporation (Thyssen Bornemisza Family)
• Inventors: Beene, Gerald Wayne
• Primary Examiner(s): Dole; Timothy J
• Application Number:
  US11/465,984
• Publication Number:
  US 20080042664A1
• Time in Patent Office: 771 Days
• Field of Search: 324/601, 324/707, 324/713, 324/720, 324/721
• US Class Current: 324/707
• CPC Class Codes: H04L 43/50 Testing arrangements

Abstract

A method for improved cable resistance measuring is provided including coupling a measurement test device including a master unit and a remote unit, via at least one connector, to at least one network cable and determining a terminating impedance using field calibration. The method additionally including transmitting an AC signal across the network cable for determining a resistance of the network cable, and measuring a length of the network cable. The method still further including measuring a capacitance of the network cable, and measuring an impedance of the network cable terminated by the measurement test device. The method additionally including extracting the resistance of the network cable from the impedance measurement, and correcting for error in at least one of capacitance, termination resistance, and nominal cable effects for a corrected resistance value.

Claims

1. A network analysis device for improved measurement of resistance, comprising:

an AC component to transmit and measure a signal for determining a resistance of a cable;

a master unit comprising a master source impedance transmitter to a receiving device resulting in a first master impedance, a plurality of diodes and a plurality of output capacitors resulting in a second master impedance, and a plurality of shunt diodes resulting in a third master impedance, and at least one coupling connector for connecting the network analysis device at the master unit to the cable;

a remote unit comprising a remote source impedance transmitter to a receiving device resulting in a first remote impedance, a plurality of diodes and a plurality of output capacitors resulting in a second remote impedance, and a plurality of shunt diodes resulting in a third remote impedance, and at least one coupling connector for connecting the network analysis device at the remote unit to the cable; and

a correction component for improving the accuracy of the resistance of the cable by correcting for error in at least one of cable capacitance deviation from nominal, cable termination deviation from nominal, and nominal cable effects.

2. The network analysis device for improved measurement of resistance of claim 1, further comprising a display component for displaying the resistance of the cable as corrected by the correction component.

3. The network analysis device for improved measurement of resistance of claim 1, wherein the correction component applies a polynomial function of the form y=A+Bx+Cx² to calculate a measured impedance as a function of a normal termination impedance.

4. The network analysis device for improved measurement of resistance of claim 1, further comprising a capacitance measurement component for measuring the cable capacitance.

5. The network analysis device for improved measurement of resistance of claim 4, wherein the capacitance measurement component shuts off one or more diodes at the remote unit for an open circuit at the remote unit, the master unit measures the cable impedance, and the capacitance measurement component calculates the cable capacitance by a formula of the form

$C=\frac{1}{2}$

π

×

Frequency ×



Xc 

.

6. The network analysis device for improved measurement of resistance of claim 1, wherein the correction component corrects for deviation from the nominal in cable capacitance per unit length by applying a polynomial function of the form:

g(length)=b0+b1×

length+b2×

length²;

calculating the error by equation of the form;

$\mathrm{Dc}=\frac{c_{\mathrm{actual}}-c_{24}}{c_{24}}<br><br><br><br>\mathrm{where}<br><br><br><br>c_{\mathrm{actual}}=\frac{\mathrm{cableC}}{\mathrm{length}};<br><br>$

and calculating the resistance corrected for capacitance and length by a formula of the form;

Res=Rel−

Dc×

g(length), where Rel is the measured resistance.

7. The network analysis device for improved measurement of resistance of claim 6, wherein the correction component corrects nominal cable characteristics by applying a polynomial function of the form:

ƒ

(R)=a0+a1×

R+a2×

R² to correct for nominal cable characteristics, where R is the measured resistance corrected for capacitance.

8. The network analysis device for improved measurement of resistance of claim 1, wherein the correction component corrects for fractional changes in the termination resistance from the nominal by applying a polynomial function of the form:

h(length)=d0+d1×

length+d2×

length²;

calculating the fractional change in termination resistance by an equation of the form;

$\mathrm{Dr}=\frac{\mathrm{rez}<br><br><br><br>2-\mathrm{rez}<br><br><br><br>2<br><br>n}{\mathrm{rez}<br><br><br><br>2<br><br>n};<br><br>$

and calculating the resistance corrected for termination resistance of the cable by a formula of the form;

Res2=Res−

Dr×

h(length).

9. The network analysis device for improved measurement of resistance of claim 8, wherein the correction component corrects for error in nominal cable characteristics by applying a polynomial function of the form:

ƒ

(R)=a0+a1×

R+a2×

R² to correct for nominal cable characteristics, where R is the measured resistance corrected for termination and capacitance.

10. The network analysis device for improved measurement of resistance of claim 1, wherein the correction component improves the accuracy of the resistance of the cable by correcting for error in the following order:

first, cable capacitance deviation from nominal;

second, cable termination deviation from nominal; and

third, nominal cable effects.

11. A method for improved cable resistance measuring, comprising:

coupling a measurement test device comprising a master unit and a remote unit, via at least one connector, to at least one network cable;

determining a terminating impedance using field calibration;

transmitting an AC signal across the network cable for determining a resistance of the network cable;

measuring agent of the network cable;

measuring a capacitance of the network cable;

measuring an impedance of the network cable terminated by the measurement test device;

extracting the resistance of the network cable from the impedance measurement; and

correcting for error in at least one of capacitance, termination resistance, and nominal cable characteristics for a corrected resistance value.

12. The method for improved cable resistance measuring of claim 11, further comprising displaying the corrected resistance value.

13. The method for improved cable resistance measuring of claim 11, wherein coupling a measurement test device, via at least one connector, to at least one network cable comprises coupling the master unit in a first position on the network cable and coupling the remote unit in a second position on the network cable, the first position and the second position being physically remote from one another.

14. The method for improved cable resistance measuring of claim 11, further comprising measuring temperature and correcting the resistance value for temperature.

15. The method for improved cable resistance measuring of claim 11, wherein measuring the capacitance of the network cable comprises:

setting up an open circuit at the remote unit;

measuring, by the master unit, an impedance of the cable; and

based on the impedance, calculating the capacitance according to an equation of the form;

$C=\frac{1}{2\times <br><br>\mathrm{\pi <br><br>}\times <br><br>F\times <br><br><br><br>\mathrm{Xc}<br><br>}.$

16. The method for improved cable resistance measuring of claim 11, wherein correcting for error in capacitance for a corrected resistance value comprises:

applying a polynomial function of the form;

g(length);

=b0+b1·

length+b2·

length²

calculating the fractional change in capacitance by equation of the form;

$\mathrm{Dc}=\frac{c_{\mathrm{actual}}-c_{24}}{c_{24}}<br><br><br><br>\mathrm{where}<br><br><br><br>c_{\mathrm{actual}}=\frac{\mathrm{cableC}}{\mathrm{length}};<br><br>$

and

calculating the corrected resistance value corrected for capacitance and length by a formula of the form;

Res=Rel−

Dc×

g(length), where Rel is the measured resistance.

17. The method for improved cable resistance measuring of claim 16, wherein correcting for cable characteristics for a corrected resistance value comprises applying a polynomial function of the form:

ƒ

(R)=a0+a1×

R+a2×

R²

to correct for nominal cable effects, where R is the measured resistance corrected for capacitance.

18. The method for improved cable resistance measuring of claim 11, wherein correcting for error in termination resistance for a corrected resistance value comprises:

applying a polynomial function of the form;

h(length);

=d0+d1·

length+d2·

length²

 

calculating the fractional change in termination resistance by an equation of the form;

$\mathrm{Dr}=\frac{\mathrm{rez}<br><br><br><br>2-\mathrm{rez}<br><br><br><br>2<br><br>n}{\mathrm{rez}<br><br><br><br>2<br><br>n};<br><br>$

and

calculating the resistance corrected for termination resistance of the cable by a formula of the form;

Res2=Res−

Dr×

h(length).

19. The method for improved cable resistance measuring of claim 18, wherein correcting for nominal cable effects for a corrected resistance value comprises applying a polynomial function of the form:

ƒ

(R)=a0+a1R+a2×

R²

to correct for nominal cable effects, where R is the measured resistance corrected for termination.

20. The method for improved cable resistance measuring of claim 11, wherein correcting for error occurs in the following order:

first, cable capacitance deviation from nominal;

second, cable termination deviation from nominal; and

third, nominal cable effects.