Patent ID: 7230970

Claim:
A method of determining the presence or absence of one or more nonlinear impairments in a linear medium, comprising: setting one or more pulse transmission parameter values; applying a first sequence of one or more first transmit pulses to the medium for transmission through the medium under the one or more pulse transmission parameter values; receiving from the medium a first sequence of one or more echo signals reflected from impairments in the medium in response to the first sequence of transmit pulses; digitizing the echo signals for each transmit pulse of the first sequence of first transmit pulses to produce a set of digital values for each transmit pulse of the first sequence of first transmit pulses; averaging the digital values for corresponding echo signals of the first sequence of echo signals to produce a first digitized set representing the average of the first sequence of echo signals; changing the one or more pulse transmission parameter values; applying a second sequence of one or more second transmit pulses to the medium for transmission through the medium under the one or more changed pulse transmission parameter values; receiving from the medium a second sequence of one or more echo signals reflected from impairments in the medium in response to the second sequence of transmit pulses; digitizing the echo signals for each transmit pulse of the second sequence of second transmit pulses to produce a set of digital values for each transmit pulse of the second sequence of second transmit pulses; averaging the digital values for corresponding echo signals of the second sequence of echo signals to produce a second digitized set representing the average of the second sequence of echo signals; combining the first and the second digitized sets to produce a residual digitized set; and examining the residual digitized set for a residual pulse indicating the presence of one or more nonlinear impairments.