Double-tone quadrature measuring method for frequency conversion system group delay
A technology of frequency conversion system and measurement method, used in transmission systems, multi-carrier systems, digital transmission systems, etc.
Active Publication Date: 2016-01-27
TSINGHUA UNIV
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[0003] In order to overcome the technical shortcomings of the existing two-tone method for measuring the group time delay of the frequency conversion system, the purpose of the present invention is to provide a two-tone orthogonal measurement method for the group time delay of the frequency conversion system, which is completely consistent with the local oscillator signal of the system under test. irrelevant, overcome the influence of local oscillator signal drift on the measurement accuracy of group delay
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[0035] The input center frequency of the simulated frequency conversion system is 1225MHz, and the corresponding output center frequency is 50MHz. The bandwidth of the analog system is 2MHz, and the sampling rate is fixed at 1GHz. Ideally, the local oscillator signal frequency of the frequency conversion system should be 1075MHz. In order to simulate the impact of the frequency drift of the local oscillator signal, the frequency of the local oscillator signal is set to 1075.0002MHz.
[0036] 1. The simulation generates two-tone signals with frequencies of 1224MHz and 1224.01MHz and random initial phases, such as figure 2 shown.
[0037] 2. Then, divide the generated dual-tone signal into two paths, one path is input to the first A / D converter, and the other path is input to the frequency conversion system after appropriate attenuation, and the output signal of the frequency conversion system is used as the second frequency conversion system after a certain attenuation. The...
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The invention provides a double-tone quadrature measuring method for frequency conversion system group delay. A vector signal source generates double-tone signals having a frequency difference of Delta f, by means of a power divider, one of the signals is input into a first A / D converter, the other one of the signals enters into a frequency conversion system after certain attenuation, the output signals of the frequency conversion system serve as the input of a second A / D converter after certain attenuation, during the measurement, the two A / D converters perform sampling synchronously, the input signals and the output signals are subjected to digital quadrature processing after being subjected to A / D sampling, and then two single-tone signals at the frequency of Delta f can be obtained, the group delay values of the frequency conversion system can be obtained by comparing the phases of the single-tone signals of the frequency of Delta f, the measurement of the group delay of the frequency points within the bandwidth of the frequency conversion system can be realized by synchronously changing the frequency values of the double-tone signals under the condition of maintaining the frequency difference Delta f of the double-tone signals unchanged, and the accuracy of the measurement results relays on the estimation accuracy of the phases of the single-tone signals of the frequency of Delta f.
Description
technical field [0001] The invention relates to a dual-tone orthogonal measurement method for group time delay of a frequency conversion system, which is used for precise measurement of group time delay of a frequency conversion system. Background technique [0002] Group delay is an important index to describe the performance of the medium and the receiving-transmitting system, and is closely related to the distortion and delay of the signal when it passes through the system. Since the input and output frequencies of the frequency conversion system are different, the measurement of the group delay of the frequency conversion system is a difficult point in the field of group delay measurement. A two-tone group delay measurement method is proposed in the document "Groupdelay and phase measurements at converters and multistage converters without LO access" (Proceedings of IEEE International Conference on Microwaves, Communications, Antennas and Electronics Systems, Tel Aviv, 2...
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IPC IPC(8): H04L27/36H04L27/38
CPCH04L27/368H04L27/3854
Inventor 王建武冯正和
Owner TSINGHUA UNIV