Testing method for transponder channel frequency response based on vector network

Abstract

A testing method transponder channel frequency response based on a vector network comprises the steps of (1), selecting a PNA-X-series vector network analyzer and a switching matrix with a vector network analyzer testing channel as testing equipment; (2), performing frequency scanning self-calibration on the vector network analyzer; (3), respectively calibrating an uplink testing channel and a downlink testing channel of the system by means of the vector network analyzer; (4), connecting the vector network analyzer with the switching matrix and a to-be-tested transponder, and constructing a testing channel; (5), setting related parameters in the vector network analyzer, finishing amplitude frequency characteristic measurement, outband inhibition measurement and group delay measurement through automatic controlling of the vector network analyzer, and simultaneously drawing a corresponding signal trace line; and (7), extracting testing result data of three testing items, and respectively deducing insertion loss and time delay of the testing channel, thereby obtaining a final channel frequency response testing result of the tested transponder.

Description

technical field [0001] The invention belongs to the field of communication satellite testing, and relates to a method for testing the channel frequency response characteristics of a communication satellite transponder, which is especially suitable for large-scale transponders with a large number of beams and channels and complex cross-link combinations on communication satellites, and can guarantee extremely Under the premise of high test accuracy, the test efficiency is greatly improved. Background technique [0002] With the continuous development of communication satellite platforms and the continuous improvement of users' demand for communication capacity, the number of antenna beams and transponders in the payload of communication satellites is increasing, and the cross-links between different beams are becoming more and more complex. Beam and phased array technologies are emerging in an endless stream, and the amount of radio frequency testing tasks has increased signi...

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Problems solved by technology

[0005] The above methods have certain limitations in actual engineering tests:

When the channel bandwidth of the transponder is wide, the test requires a wide expansion bandwidth and a small frequency step, the number of test points for a single transponder will be very large, so the test efficiency of multi-channel large-scale transponders is extremely low, and it may even affect the overall performance. Star development progress;

[0009] (4) During the testing of amplitude-frequency characteristics and out-of-band suppression characteristics, the system only monitors the power of the uplink and downlink signals of the transponder, without considering the connection mismatch between instruments and the non-ideal frequency response of the test instrument itself. And the use of spectrum analyzers to measure single-point power itself has a high degree of uncertainty

During the test of group delay characteristics, the phase-frequency characteristic error brought by the test link itself is not considered, so the measurement accuracy of the system is not enough;

[0010] (5) The system uses the modulation method to complete the test of the group delay characteristic, and it also needs to implement a relatively complex digital signal processing algorithm in the host computer software, so the system function has certain development, implementation and debugging difficulties, and the overall robustness of the test system Not strong

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