ADAPTIVE PULSE WIDTH TIME DOMAIN REFLECTOMETER
First Claim
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1. A method for using a time domain reflectometer (TDR) to locate a fault in a digital subscriber line (xDSL) having a characteristic impedance, the method comprising:
- a) providing a TDR transmitter and receiver;
b) transmitting at least one launch pulse into the xDSL with the TDR transmitter and initiating a start time in a timebase;
c) receiving a return signal trace from the xDSL with the TDR receiver;
d) amplifying the return signal trace from the xDSL with an adjustable gain amplifier;
e) digitizing the amplified return signal trace to generate an array of digital samples and sampling time information from the timebase;
f) recording the array of digital samples and sampling time information; and
g) differentiating the array of digital samples numerically by generating an arithmetic difference between at least two digital samples sampled at sampling times separated by an adjustable time offset;
wherein the adjustable time offset is increased as a function of elapsed time from the start time.
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Abstract
An adaptive pulse width (APW) Time Domain Reflectometer (TDR) comprises an enhancement to the standard Pulse TDR by adjusting the effective pulse width as a function of time. Improved resolution for a large range of cable lengths is obtained, as well as allowing an all-in-one view of the processed return signal trace.
29 Citations
14 Claims
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1. A method for using a time domain reflectometer (TDR) to locate a fault in a digital subscriber line (xDSL) having a characteristic impedance, the method comprising:
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a) providing a TDR transmitter and receiver; b) transmitting at least one launch pulse into the xDSL with the TDR transmitter and initiating a start time in a timebase; c) receiving a return signal trace from the xDSL with the TDR receiver; d) amplifying the return signal trace from the xDSL with an adjustable gain amplifier; e) digitizing the amplified return signal trace to generate an array of digital samples and sampling time information from the timebase; f) recording the array of digital samples and sampling time information; and g) differentiating the array of digital samples numerically by generating an arithmetic difference between at least two digital samples sampled at sampling times separated by an adjustable time offset; wherein the adjustable time offset is increased as a function of elapsed time from the start time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification