Measuring device with ALC circuit

Abstract

The invention provides a measuring device with an ALC circuit, and the ALC circuit is formed in the manner that an output end of an adjustable radio-frequency attenuator is connected with an input end of a power distribution unit; an output end of the power distribution unit is connected with an input end of a detector; an output end of the detector is connected with an input end of an analog-digital converter; an output end of the analog-digital converter is connected with an input end of a digital chip; and an output end of the digital chip is connected with an input end of the analog-digital converter. The digital chip comprises a zero point module, a comparison integrator, an ALC open-loop control module and a logarithmic amplifier, wherein the output end of the zero point module is connected with the input end of the comparison integrator. The output end of the comparison integrator is connected with the input end of the ALC open-loop control module. The output end of the ALC open-loop control module is connected with the input end of the logarithmic amplifier, and the logarithmic amplifier is set behind the comparison integrator, thereby greatly reducing the periodic distortion of AM under a part of modulation frequency.

Description

technical field [0001] The invention relates to the technical field of signal measurement and testing, in particular to a measuring device with an ALC circuit. Background technique [0002] The RF signal source is a common device in the field of measurement and testing. The main function of the radio frequency signal source is to generate radio frequency signals in a certain frequency range and amplitude range, as the excitation or reference of the device under test. It can also output various modulation signals, such as FM (Frequency Modulation, frequency modulation), AM (Aptitude Modulation, amplitude modulation), PM (Phase Modulation, phase modulation), IQ, Pulse (pulse), etc., to provide a basis for debugging of communication equipment. The amplitude accuracy and stability of the output signal of the RF signal source is one of the important indicators of the RF signal source, and AM is also an important measure of the performance of the RF signal source, and these indic...

AI Technical Summary

Problems solved by technology

Digital processing is difficult to accurately deal with rapidly changing signals, especially when the frequency of the signal changes continuously, which will cause a large deviation at the AM negative peak

This deviation is related to the AM modulation frequency. In the vicinity of some modulation frequencies, the actual modulation signal (baseband signal) of the modulated signal will periodically generate large distortion

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