＜正＞ This paper analyses the principles of the recommended method for measuring errors of PAL chrominance signal demodulation angle, which is constituted in IEC Publication 107-1[1]. Analysis shows that by means of above method, the measured phase matching error and amplitude matching error of delayed and undelayed signals are mixed with other errors. Thus the measurement results, especially for phase matching error, cannot correctly reflect the errors in associated circuits and cannot be used for assessing the properties of the comb filter or the receiver. In this paper, authors propose that the measuring signal and the measured point in the receiver should be changed. Practical measurement and observation of the line crawl on screen show that the modified method is more effective and more reasonable.
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