Measuring device with ALC

Abstract

The invention discloses a measuring device with an ALC. The ALC is characterized in that the input end of a variable attenuation unit is connected with the input end of the ALC, the output end of the variable attenuation unit is connected with a power distribution unit, the first output end of the power distribution unit serves as the output end of the ALC, the second output end of the power distribution unit is connected with the input end of a detector, the detector is connected with the input end of a log amplifier, the log amplifier is connected with the first input end of an addition unit, the second input end of the addition unit is connected with the reference voltage, the output end of the addition unit is connected with the input end of an integrator, the integrator is connected with the input end of a voltage conversion unit, and the voltage conversion unit is connected with the adjusting end of the variable attenuation unit. The log amplifier, the addition unit, the integrator and the voltage conversion unit are achieved through a digital chip, an analog-digital converter is arranged between the detector and the log amplifier, and an analog-digital converter is arranged between the voltage conversion unit and the variable attenuation unit. The temperature stability of the ALC is good.

Description

technical field [0001] The invention relates to the technical field of measurement and testing, in particular to a measuring device with an ALC circuit. Background technique [0002] In the field of measurement and testing, the RF signal source is a necessary measurement and testing instrument for RF and microwave workers. The radio frequency signal source is a radio frequency signal transmitting device, which can output continuous wave radio frequency signals with various parameters such as frequency and amplitude. Of course, it can also output various modulation signals, such as FM, AM, PM, IQ, Pulse and other modulation signals. 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 these indicators are generally realized by the ALC circuit (Automatic Level Control automatic level control circuit). [0003] The Chinese patent application document with the patent application number ...

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Problems solved by technology

[0027] 1. Since the entire automatic level control circuit is implemented by an analog circuit, temperature has a great influence on the entire circuit, and it is difficult to eliminate the influence of temperature through various means such as temperature compensation, which in turn affects the amplitude accuracy of the automatic level control circuit and stability;

[0028] 2. Since the AM modulation and ALC circuits are designed together, it is extremely difficult to design the entire circuit;

[0029] 3. There are certain limitations in the constant current drive and constant voltage drive modes of the variable attenuator, which cannot meet the needs of the variable attenuator in the measurement device

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