An Automatic Control Method of IF Gain of Vector Network Analyzer Using Hardware Control

Abstract

A hardware-controlled automatic intermediate-frequency gain control method for a vector network analyzer includes the steps of obtaining signal power values of current frequency points by the aid of a pre-detecting circuit, setting a gain switch window by the aid of a window comparison circuit, performing comparison operation on signals obtained by detection, utilizing output of a comparator to directly control an intermediate-frequency gain switch, and sending switch states to a CPU (central processing unit). Automatic gain control is realized by the circuit, and the CPU directly acquires current frequency point data and current gain state flags and performs operation without sending out control commands and rescanning, so that a dynamic range index is increased on the premise that measuring speed of a complete machine is unaffected. Compared with the prior art, the method has the advantage that the measuring speed of the complete machine is unaffected.

Description

technical field [0001] The invention relates to an automatic control method for intermediate frequency gain, in particular to an automatic control method for intermediate frequency gain of a vector network analyzer using hardware control. Background technique [0002] Dynamic range is an important indicator of vector network analyzers, and the automatic control technology of intermediate frequency gain is one of the technologies widely used to improve dynamic range. In order to improve the dynamic range index, the currently widely used method is to add a controllable gain circuit to the IF channel. When the power of the IF signal is reduced to a certain set value, the host computer controls the increase of the IF gain to reduce noise. The mid-range host compensates the analog gain of the mid-frequency channel. When a small signal is input, the A / D converter still works in the linear region, thereby improving the dynamic range index of the whole machine. The process is: at ...

AI Technical Summary

Problems solved by technology

[0004] The disadvantage of the existing technology is: if a certain frequency point needs to switch the gain state, the CPU needs to set the hardware and scan the frequency point repeatedly, and the time spent on the frequency point that needs to switch the gain state will be more than the normal frequency point, affecting Machine measurement speed

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