Device and method for achieving spread spectrum function of spectrum analyzer

Abstract

The invention belongs to the technical field of signal processing, and relates to a device and method for achieving the spread spectrum function of a spectrum analyzer. The device comprises a waveguide adaptor, a first waveguide switch, a second waveguide switch, a high-pass filter, a low-pass filter, a fundamental wave mixer, a dot frequency local oscillator and an intermediate frequency filter amplifier. The method includes the steps that firstly, FIF of the intermediate frequency range of a spread spectrum device is defined according to the coverage area of a preselector of a host, and then FLO of frequency of the dot frequency local oscillator is configured according to FRF of the frequency range of the device and the FIF; secondly, the design of the filters is optimized, wavebands are divided, the frequency conversion formula (FRF-FLO) is used for a low-frequency band, and the low-pass filter is matched; the frequency conversion formula (FLO-FRF) is used for a high-frequency band, and the high-pass filter is matched, and then the spread spectrum function of the spectrum analyzer is comprehensively achieved. According to the device and method, when the frequency range is higher than 67GHz, the spread spectrum function of the spectrum analyzer for image signal curbing can be also achieved.

Description

technical field [0001] The invention relates to a spectrum analyzer spread spectrum technology, in particular to a device and method for realizing the spectrum analyzer spread spectrum function, and belongs to the technical field of signal processing. Background technique [0002] At present, there are many kinds of instruments for testing the spectrum parameters of the signal. The instrument for measuring frequency parameters alone is a frequency meter, the instrument for measuring signal amplitude alone is a power meter, and the instrument that integrates the two functions into one is a spectrum analyzer, which is characterized by a wide range of frequency measurement and a large range of amplitude measurement . [0003] There are currently two types of signal input connectors: coaxial and waveguide. Coaxial connectors are suitable for lower frequency ranges and waveguide connectors are suitable for higher frequency ranges. The coaxial continuous measurement range of th...

AI Technical Summary

Problems solved by technology

However, it often has the following defects: 1. At present, the front-end of the mixer is usually used to filter out the image response (during the mixing process, there are two input signals that can produce the same intermediate frequency signal as the local oscillator signal of the same frequency. One intermediate frequency lower than the local oscillator, one intermediate frequency higher than the local oscillator, one of the signals is called the image response of the other signal) preselector, which cannot be realized in the frequency band above 67GHz; 2, the current general spread spectrum module adopts high harmonic order , The low-IF frequency output mode directly enters the IF channel of the host, and the image signal cannot be filtered out; 3. At present, the image response suppression of the general-purpose spread spectrum module mostly adopts the built-in content software algorithm of the instrument, and utilizes the characteristic that the stray signal changes with the frequency of the local oscillator , divided into two scans, the local oscillator frequency difference is 2IF / n (IF is the intermediate frequency frequency of the spectrum analyzer, n is the harmonic frequency mixing frequency of the spread spectrum module), and the measurement results are taken to be small, so that it does not follow the local oscillator The changing signal is a real signal, but due to the software algorithm, the signal amplitude is smaller than the real value, and each time the results need to be superimposed twice, resulting in slower measurement speed, which does not meet the accuracy of spectrum analyzer amplitude measurement High and fast measurement speed requirements; 4. The image response suppression also uses the instrument external control software algorithm or manual calculation method to calculate the frequency interval of each response point according to the intermediate frequency frequency and harmonic times of the specific instrument, and through harmonic mixing The calculation method can distinguish the real signal from the spurious signal, which not only requires strong professional knowledge of the instrument, but also requires a long calculation time to separate the spurious signal, and the measurement speed is slower, which does not meet the test requirements; 5. The existing The spread spectrum method adopts the harmonic mixing method to increase the frequency conversion loss, which reduces the small signal measurement capability for the host

Images