A delay calibration device and method for a coherent vector signal generation system

Abstract

The invention discloses a time delay calibration device and method oriented to a coherent vector signal generation system. Through the edge-to-edge time measurement function of an oscilloscope, the time delay between each coherent signal output channel and a reference channel is obtained and compensated; and then the oscilloscope is used to Measure the phase difference and instantaneous frequency at the start and end positions of each coherent chirp signal, use the relationship between the chirp signal delay, phase difference, and instantaneous frequency to form an equation, and calculate the distance between the output channel of each coherent signal and the reference channel Accurate time delay and control compensation, so as to complete the time delay calibration between channels of the coherent vector signal generation system.

Description

technical field [0001] The invention belongs to the technical field of coherent signal generation system calibration, and more specifically relates to a precise calibration device and method for inter-channel time delay oriented to a coherent vector signal generation system. Background technique [0002] The coherent vector signal generation system is a multi-channel radio frequency coherent signal generation system. The system has multiple radio frequency signal output channels and can generate multi-channel coherent radio frequency signals. The frequency of each signal is consistent, the phase is coherent, and the time delay and amplitude controllable; the coherent vector signal generation system can generate various types of coherent signals, such as phase parameter word modulation signals, coherent radar pulse modulation signals, and even coherent noise signals. The coherent vector signal generation system has a wide range of applications, and can be used for wireless co...

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Problems solved by technology

[0004] When calibrating the time delay of coherent vector signal generation system, the system is often controlled first to generate multi-channel coherent pulse modulation signals, and the time delay between the signals is measured by the amplitude demodulation function of the high sampling rate oscilloscope. Factors such as noise, consistency between multiple signals, and oscilloscope measurement errors lead to limited measurement accuracy of this measurement method: Take a 40GHz high-sampling rate oscilloscope as an example, when the measurement average is not enabled, the measurement error is > 20 ps; even if it is enabled The average function in the oscilloscope, and the number of averages > 256 times, the delay measurement error is still greater than 5ps

[0005] In addition, the cross-correlation calculation of coherent signals can also be used to measure the delay difference of coherent signals, but limited by the sampling rate of the oscilloscope, taking the oscilloscope with a high sampling rate of 40GHz as an example, the measurement error of this method is >12.5ps, and the calculation amount is large

[0006] With the increase of coherent signal modulation bandwidth, the above delay measurement error has more and more serious influence on the coherent characteristics of coherent vector signal generation system. Taking QPSK signal as an example, when the symbol rate is 100MHz, the delay measurement of ±5ps The error leads to about ±0.3° coherence angle deviation; and when the symbol rate increases to 1GHz, the delay measurement error of ±5ps leads to about ±3° coherence angle deviation, the above delay measurement error seriously affects the high symbol rate , Coherent properties of high bandwidth signals

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