Spectrum analyzer with digital intermediate-frequency signal processing system and implementation method thereof

Abstract

The invention relates to a spectrum analyzer with a digital intermediate-frequency signal processing system and an implementation method thereof. The implementation method of the digital intermediate frequency comprises the following steps of: generating two paths of signals with phase difference of 90 degrees by a digital transducer, and mixing the two paths of signals and signals SD sampled and output by an analog-to-digital converter to obtain in-phase signals ID and orthogonal signals QD; filtering out high-frequency components in two paths of the in-phase signals and orthogonal signals by using two base band filters to obtain the filtered in-phase signals I'D and orthogonal signals Q'D; performing frequency counting and amplitude detection on the two paths of filtered signals; performing video filtering on an amplitude detection result, and obtaining the final spectrum analysis result through display detection; wherein the step of performing frequency counting comprises the following sub steps of: measuring deviation of signals relative to intermediate frequency to obtain a frequency value of a signal to be detected; and judging whether the frequency value of the signal to be detected is more than or less than the intermediate frequency according to the in-phase signals I'D and orthogonal signals Q'D.

Description

technical field [0001] The invention relates to a spectrum analyzer with a digital intermediate frequency signal processing system and a digital intermediate frequency realization method thereof, belonging to the technical field of signal processing. Background technique [0002] Spectrum analyzers are usually used to measure the frequency and power of signals and display them on the display. They are generally divided into two types. One is a dynamic signal analyzer, that is, a fast Fourier transform analyzer, which is an instrument that performs FFT transformation on a signal within a specific time period to obtain frequency, amplitude and phase information. Periodic signal, but with a lower upper frequency measurement limit. The other is the sweeping spectrum analyzer, which is a superheterodyne adjustable pre-selection receiver, which can analyze the signal or the intermediate frequency signal transformed from the signal. It has a high measurement frequency range, whic...

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Problems solved by technology

For such data, usually the data will be directly sent to the DSP processor for processing, that is, the display detection is realized by using the DSP processor. This method can make full use of the flexibility of the DSP processor, and it is very convenient to realize the required Display detection processing, however, this method requires a large amount of data transfer between the digital intermediate frequency ASIC and the DSP processor, and also requires the DSP processor to process a large amount of data, which will take up a lot of DSP processor time

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