Heterodyne sweep-frequency type spectrum analyzer based on low frequency detection

Abstract

The invention relates to the technical field of spectrum analyzers, specifically to a heterodyne sweep-frequency type spectrum analyzer based on low frequency detection. The heterodyne sweep-frequency type spectrum analyzer based on low frequency detection includes a to-be-detected signal conditioning module, a mixer module, a local oscillator signal generation module, a low frequency signal processing module, an AD sampling module, an FPGA module and a display screen module; two inputs of the mixer module are connected with the to-be-tested signal conditioning module and the local oscillator signal generation module respectively, the output of the mixer module is connected with the input of the low frequency signal processing module, the output of the low frequency signal processing module is connected with the input of the AD sampling module, and the FPGA module is connected with the local oscillator signal generation module, the AD sampling module and the display screen module. The spectrum analyzer realizes accurate measurement of any spectrum, has the characteristic that a superheterodyne frequency spectrograph has a wide range of application, simplifies system complexity, improves measurement accuracy of the system, and avoids the problem of image frequency interference brought by a band-pass filter that intermediate frequency detection adopts.

Description

technical field [0001] The invention belongs to the technical field of spectrum analyzers, in particular to a heterodyne frequency sweeping spectrum analyzer based on low-frequency detection. Background technique [0002] A spectrum analyzer is an effective tool for analyzing the frequency domain characteristics of electrical signals. By analyzing the frequency domain of the signal, the frequency, power, harmonics, clutter, noise, interference, distortion and other information of the measured signal can be obtained, and some parameters of the amplifier and filter circuit system can be measured. It is a multi-purpose Electronic measuring instruments can also be called frequency domain oscilloscopes. [0003] Spectrum analyzers can be divided into digital spectrum analyzers and analog spectrum analyzers. [0004] Digital spectrum analyzer can be divided into digital filtering method and FFT method. The digital filtering method samples the signal to be tested and directly pa...

AI Technical Summary

Problems solved by technology

In order to avoid image frequency interference, it is often required that the dynamic range of the local oscillator frequency of the spectrum analyzer is twice the signal measurement range, which makes the system complex, resulting in problems such as expensive, inconvenient to carry, complex structure, and poor specificity.

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