Method for ADC phase frequency response testing

Abstract

The invention discloses a method for ADC phase frequency response testing. The method comprises the steps of measuring frequency reduction conversion delay time of an analog frequency mixer and a low-pass filter (MLPF) to a specific carrier frequency narrow bandwidth frequency modulation (FM) signal based on a high-definition oscilloscope (HDO) and a phase expansion sine approximation method (PUSAM); determining a required effective sampling frequency in acquiring the FM signal by an ADC based on an Nyquist sampling theorem, a bandpass sampling theorem and a protective bandwidth, thereby ensuring an effective frequency spectrum array of the FM signal; acquiring a high-carrier-frequency FM signal and a low-carrier-frequency FM signal before and after MLPF frequency reduction conversion by the ADC by an effective sampling frequency, realizing demodulation of an acquired FM signal based on PUSAM, correcting the modulated signal initial phase of the low-carrier-frequency FM signal by meansof the measured analog MLPF frequency reduction conversion delay time, and calculating the phase frequency response of the ADC in the high-carrier-frequency through the modulated signal initial phaseof two FM signals after correction. The method can accurately and quickly realize ADC phase frequency response testing and furthermore has advantages of simple testing process, wide frequency range with frequency which can be higher than the highest sampling frequency of the ADC, and multichannel simultaneous testing.

Description

technical field [0001] The invention belongs to the technical field of ADC frequency response testing, and more specifically relates to a method for testing ADC phase-frequency response. Background technique [0002] As an indispensable core component of today's measuring instruments, ADC is widely used in precision instruments, test and measurement, aerospace, communication and other fields. Frequency response is a key characteristic parameter of ADC. Currently, the amplitude-frequency response test technology of ADC is relatively mature, but there are still many problems to be solved urgently in the phase-frequency response test technology. The phase-frequency response of the ADC directly affects the real-time performance of the acquisition signal, and further affects the performance of ADC-based measuring instruments. Especially for real-time motion control, real-time monitoring, inertial navigation and other fields, the higher the real-time performance of the ADC acquisi...

AI Technical Summary

Problems solved by technology

[0004] Therefore, in view of the shortcomings such as limited test accuracy and limited test frequency range in the existing ADC phase-frequency response test method, the present invention proposes a method with high test accuracy, fast speed, wide frequency range, and a maximum sampling frequency higher than that of the ADC. , ADC phase-frequency response test method that can realize multi-channel test at the same time

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