Broadband frequency response measuring method and broadband frequency response measuring device

Abstract

The invention relates to a broadband frequency response measuring method and a broadband frequency response measuring device. The measuring method comprises the steps of carrying out second processingon an output signal generated by a radio frequency channel of a receiver in response to a transmitting signal to obtain a receiving sequence, and the transmitting signal being generated by a radio frequency channel of a transmitter in response to a signal obtained by carrying out first processing on a ZC sequence; and calculating to obtain a frequency response measurement result of the radio frequency channel to be measured according to the ZC sequence and the receiving sequence. The ZC sequence is applied to the broadband frequency response measurement process of the transmitter or the receiver; the limitation that frequency sweeping is carried out by utilizing a single-tone signal in the past is overcome; a new measurement scheme is provided, the amplitude-frequency characteristics in the frequency response of the to-be-measured radio frequency channel can be obtained, the phase-frequency characteristics in the frequency response of the to-be-measured radio frequency channel can also be obtained, and correction and compensation of the to-be-measured channel according to the obtained amplitude-frequency characteristics and phase-frequency characteristics in the later period are facilitated.

Description

technical field [0001] The invention relates to a signal test and measurement technology, in particular to a wideband frequency response measurement method and a measurement device thereof. Background technique [0002] In the field of test and measurement, signal generators (including arbitrary waveform generators, radio frequency signal sources, vector signal generators, etc.) For waveform-shaped signals, the spectrum analyzer is used to receive and measure various signals, for example, it can measure the power (amplitude), frequency, phase, bandwidth, etc. of the signal, and even perform various modulation and demodulation analysis on the signal. These instruments and equipment often include analog signal channels and digital signal channels, and there are a large number of analog devices in the analog signal channels, such as amplifiers, filters, mixers, etc., the amplitude-frequency of the analog circuit composed of these analog devices The response curve (referred to ...

AI Technical Summary

Problems solved by technology

On the one hand, the frequency sweep method requires sweeping at equal intervals. The size of the frequency step not only affects the speed of amplitude-frequency response measurement, but also affects the measurement accuracy and final calibration accuracy. If the sweep frequency step is set too small, the acquisition It takes a long time to simulate the amplitude-frequency response of the channel, which affects the measurement and calibration efficiency, and if the frequency sweep step is too large, the obtained amplitude-frequency characteristic response curve may not be able to represent the real channel characteristics; another On the one hand, this method of using a single tone signal as a calibration signal can only obtain the amplitude-frequency response of the analog channel, but cannot obtain the phase-frequency response of the analog channel

In addition, there is still a third technical problem. This frequency sweep method based on a single tone signal cannot effectively obtain the wideband amplitude-frequency characteristics and phase-frequency characteristics of analog devices such as amplifiers, filters, and mixers in the analog channel. Characteristics, for example, for some high-order broadband modulation signals such as high-order QAM signals, the slight amplitude unevenness and nonlinear phase of the analog channel will degrade the signal quality, resulting in the inability to demodulate the transmitted or received signal; specifically , when measuring a bandwidth of 2Δf (such as [f c -Δf,f c +Δf]) for the frequency response of the analog channel, if the frequency sweep method based on a single tone signal is used, since the signal generator or the mixer in the receiver always works at the center frequency f c Therefore, only the amplitude-frequency characteristics at the center frequency can be obtained each time, but the amplitude-frequency characteristics at other frequency points within the bandwidth cannot be obtained

[0005] For another example, another existing technology is to use white noise as a signal source to measure the broadband frequency response of an analog channel. This method utilizes the characteristic that the power spectral density of white noise is evenly distributed in the entire frequency band, and the acquisition is performed in the receiver. To estimate the power spectrum of the noise signal passing through the channel under test, it is necessary to use the average value of multiple estimation results to obtain an approximate amplitude-frequency response, and the phase-frequency response of the analog channel cannot be obtained

There are also some problems in this measurement method. Because the power spectrum of white noise only has the characteristics of uniform distribution, the amplitude-frequency characteristics of the spectrum itself are not flat, but present "noise" characteristics. Therefore, the use of white noise to realize the analog channel The frequency response of the frequency response requires a very large number of average processing, which is not suitable for practical applications, especially for the application of broadband high-order modulation signals

Images