Patent ID: 9678146
Date: 2017-06-13
CPC Classifications: G01R,H04L

Claim:
1. A temperature insensitive testing device capable of outputting a test signal through a transmission line and generating a test result, comprising: a transmission-end test sequence generating circuit operable to generate a test sequence; a transmission circuit including: a reception circuit including: a correlation-value generating circuit operable to execute a correlation calculation according to the test sequence and the digital echo signal to thereby generate a plurality of correlation values including a maximum correlation value, the correlation-value generating circuit including: a multiplier to multiply the test sequence by the digital echo signal and generate a current multiplication value, an adder to sum up a preceding addition value and the current multiplication value and generate a current addition value, and a delay element to delay the current addition value and generate the preceding addition value, in which one of the adder and the delay element is operable to output the plurality of correlation values; and a decision circuit operable to determine whether the maximum correlation value is greater than at least one threshold, so as to generate a decision result, wherein the predetermined frequency restricts a variation of the maximum correlation value within a predetermined range provided that the temperature variation of the transmission line stays within a temperature variation range; the analog-to-digital converter samples the echo signal according to a sampling delay arrangement to thereby generate A sets of reception sequences successively, in which the A is an integer greater than 1 and the correlation-value generating circuit carries out the correlation calculation by correlating each of the A sets of reception sequences with the test sequence to thereby generate at least a part of the plurality of correlation values; the decision circuit is operable to further determine whether one of the at least a part of the correlation values is greater than the at least one threshold to thereby generate an initial decision result, and if the initial decision result indicates that the one of the at least a part of the correlation values is greater than the at least one threshold, the analog-to-digital converter makes an alteration in the sampling delay arrangement according to the initial decision result to thereby generate B sets of reception sequences successively, in which the B is an integer greater than 1 and the sampling density of the sampling delay arrangement after the alteration is higher than the sampling density of the sampling delay arrangement before the alteration.