A device and method for realizing the spread spectrum function of a signal analysis instrument

Abstract

The invention belongs to the technical field of signal processing, and relates to a device and a method for realizing the frequency spread function of a signal analyzer. The device comprises a waveguide adapter, a first waveguide switch, a second waveguide switch, a high-pass filter, a lowpass filter, a basic wave frequency mixer, a dot frequency local oscillator and a medium frequency filter amplifier; the method comprises the steps of defining a medium frequency range FIF of a frequency spread device according to the cover range of a host preselector, then configuring a dot frequency local oscillator frequency FLO according to the device frequency range FRF and FIF, and optimizing the filter design to perform waveband partitioning, wherein a frequency conversion formula (FRF-FLO) is used for the low-frequency band and is matched with the low-pass filter; a frequency conversion formula (FLO-FRF) formula is used for the high-frequency band and is matched with the high-pass filter, so the frequency spread function of the signal analyzer is comprehensively realized. The device has the function of restraining the frequency spread function of the signal analyzer by a mirror signal when the frequency range is higher than 67GHz.

Description

Technical field [0001] The invention relates to the spread spectrum technology of a signal analysis instrument, in particular to a device and a method for realizing the spread spectrum function of a signal analysis instrument, and belongs to the technical field of signal processing. Background technique [0002] There are many instruments for parameter testing of signals. The instruments and equipment for measuring single pair of frequency parameters are frequency meters, and the instruments and equipment for measuring single pair of signal amplitude are power meters. The two functions are integrated into one is the signal analysis instrument, which is characterized by a wide measurement frequency range and a large amplitude measurement range. . [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 continuo...

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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 signal analysis instrument, n is the harmonic 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 the results need to be superimposed twice each time, resulting in slower measurement speed, which does not meet the amplitude measurement accuracy of the signal analysis instrument 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

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