Attenuation parameter measurement device based on lock-in amplifier

Abstract

The invention discloses a phase-locked amplifier based attenuation parameter measurement device. The device comprises a radio frequency signal source, an excitation signal input end, an attenuation signal input end, a local oscillator source, a frequency mixer, a program-controlled stepping standard attenuator and a phase-locked amplifier. According to the scheme, a method of replacing combination by radio frequency series connection and low and medium frequency series connection is adopted to carry out improvement on the system, a method of phase-locked amplifier correlation detected is introduced, the phase-locked amplifier is used to act as a medium frequency receiving device, useful signals are extracted from weak signals, and influences imposed on attenuation measurement by noise interference in the surrounding environment are eliminated. The bandwidth is compressed and the noises are suppressed to the maximum degree through the scheme disclosed by the invention, thereby enabling the measurement accuracy and the dynamic range of the system to be greatly improved, and thus solving an interference problem of various noises in the high attenuation measuring process.

Description

technical field [0001] The invention relates to the field of attenuation parameter measurement. More specifically, it relates to a device for measuring attenuation parameters using a lock-in amplifier. Background technique [0002] Microwave radio attenuation is a very important and popular parameter in the radio field, and both at home and abroad attach great importance to the establishment of attenuation parameter standards. Attenuation measurement and verification devices widely used at present require a high-sensitivity measurement receiver, so the measurement receiver is a key part of the test system. The measurement receiver is used to process the received intermediate frequency signal, and requires a large dynamic range and good linearity. . [0003] At present, the attenuation measurement in the world adopts series low intermediate frequency replacement technology, and the replacement is performed at a lower fixed intermediate frequency, so that the attenuator used...

AI Technical Summary

Problems solved by technology

Newly developed measurement receivers in the world, such as FSMR of RS Company and N5531 of Agilent Company, are multi-parameter measurement receivers. Their working principles are realized through software on the basis of spectrum analyzers, and the price The cost is more than one million yuan, which brings a great cost burden to the metering institution; for the country, the coaxial attenuation standard developed by the National Defense Second Center during the Eleventh Five-Year Plan also adopts the series low-intermediate frequency replacement technology, and uses the induction voltage divider as the standard attenuation The receiving end adopts the method of true effective value detection to convert the AC signal into a DC signal, and then the high-level A / D converter performs data sampling, and then transmits the data to the computer for data processing and display

The disadvantage of all the above methods is that the requirements for the environment are very high. When measuring large attenuation, any small vibration or electromagnetic interference around and ground noise may cause large fluctuations in the measurement results, resulting in reduced measurement accuracy.

At present, the environmental requirements of many laboratories are difficult to meet the uncertainty requirements of the test.

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