Biphase digital phase-locking amplifier and digital domain synchronous phase-locking algorithm thereof

Abstract

The invention relates to a biphase digital phase-locking amplifier (as shown in chart 1) and a digital domain synchronous phase-locking algorithm of the biphase digital phase-locking amplifier. The biphase digital phase-locking amplifier can be used for detecting weak current signals, and realize the functions of automatic filtering tracking and synchronous phase-locking. The biphase digital phase-locking amplifier can solve the problems that the volume of the existing phase-locking amplifier is large, the temperature excursion exists, and the speed is slow when the existing phase-locking amplifier is connected with a computer to carry out automatic measurement and control. The biphase digital phase-locking amplifier has the technical characteristics that the weak current signals pass through a 9-step RLC (radio link control) mixed type high-pass filter by a precise I / V conversion circuit, and is then connected with two low-noise instrument amplifiers, the connecting modes of which are different; the rear ends of the instrument amplifiers are respectively connected with an 8-step RLC mixed type high-pass filter, and a differential signal is formed by signals output by two low-pass filters. Meanwhile, reference signals pass through a 90-degree phase shifter of a phase-locking loop to output two TTL square waves, the phase difference of two phases of which is 90 degrees. Signals of three paths are collected by a data acquisition card, and are then transmitted to a PC (personal computer) machine. The biphase digital domain synchronous phase-locking algorithm (as shown in chart 2) provided by the invention is applied on the PC machine to carry out signal processing and filtering.

Description

technical field [0001] The invention relates to a dual-phase digital lock-in amplifier and a digital lock-in algorithm used for detecting weak current signals output by differential detectors of terahertz time-domain spectrometers, and can also be used in other weak signal detection fields. Background technique [0002] Lock-in amplifiers are widely used in the field of weak signal detection. Most of the foreign-made lock-in amplifiers sold in the market, such as PE7220, SR830 and other typical general-purpose lock-in amplifiers, are too bulky to be integrated into the system. If automated testing equipment is required, lock-in amplifiers such as PE7265 and SR830 will slow down the entire system due to the limitation of communication speed. [0003] There are many institutions or companies that have also studied various lock-in amplifiers. The characteristics of each lock-in amplifier are analyzed one by one below. a. Gong Xiangpeng (public number CN1885043, Institute of E...

AI Technical Summary

Problems solved by technology

[0004] The present invention solves the problem of using miniaturized lock-in amplifiers in some precision instruments such as terahertz time-domain spectrometers, and meets the needs of rapid response of the instruments

Solve the problem of phase drift caused by the jitter or drift of the output frequency of the chopper in the terahertz time-domain spectrometer

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