Method for measuring frequency-phase characteristic of electrical network

Abstract

The invention relates to a method for measuring the frequency-phase characteristic of an electrical network, comprising the following steps of: (1) reading sweep frequency signals by a singlechip and judging the frequency value F of the signals; (2) calculating the frequency value F1 of counting signals by the singlechip according to the frequency value F of the sweep frequency signals; (3) outputting sweep frequency signals failing to pass the measured electrical network and the sweep frequency signals passing through the measured electrical network to a phase discriminator to obtain phase difference signals; (4) combining the phase difference signals output by the discriminator and the counting signals to obtain count pulse; (5) outputting the count pulse to a counter to obtain the count value B of pulse count; and (6) calculating the phase difference value N according to the count value B. The method for measuring the frequency-phase characteristic of the electrical network can realize equal-precision measurement of electrical network with different signal frequencies.

Description

Technical field: [0001] The invention relates to a method for measuring the phase-frequency characteristics of a circuit network used in a digital frequency characteristic tester. Background technique [0002] To measure the amplitude-frequency and phase-frequency characteristics of a circuit network system, it is generally necessary to use a frequency characteristic tester, that is, a frequency sweeper. The analog frequency sweeper is expensive, bulky, and complicated to operate, which brings a lot of inconvenience to users. Gradually unable to meet the requirements of users. The digital frequency characteristic tester has gradually replaced the analog frequency sweeper and has become the direction of research and design. A method for measuring the phase-frequency characteristics of a circuit network in the prior art is to pass the frequency sweep signal that has not passed through the circuit network under test and the frequency sweep signal that has passed through the ci...

AI Technical Summary

Problems solved by technology

[0003] This method of measuring the phase-frequency characteristics of a circuit network is accurate in testing the phase-frequency characteristics of a single-frequency circuit network system, but when measuring circuit networks with different signal frequencies, the frequency of the frequency sweep signal is often added. The frequency of the signal needs to change with the frequency of the circuit network signal, and this method of measuring the phase-frequency characteristics of the circuit network and the invariance of the external clock signal make the detection accuracy of the low-frequency signal much higher than that of the high-frequency signal, resulting in The instability of the overall phase difference value measurement, the accuracy of the measured phase difference value will change with the change of the circuit network signal frequency, and the equal precision measurement of the circuit network with different signal frequencies cannot be realized

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