Digital down converter-Hilbert-Huang transform based instantaneous frequency measuring method

A technology of digital down-conversion and instantaneous frequency, which is applied in the direction of frequency measuring devices, measuring devices, measuring electrical variables, etc., can solve the problems of low resolution, time-consuming, modal confusion, etc., and solve the problems of low frequency resolution, Excellent anti-noise effect

Inactive Publication Date: 2011-03-23
XIDIAN UNIV
View PDF0 Cites 15 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The wavelet transform (WT) analysis method is not very purposeful for signal analysis and takes a lot of time
For two superimposed signals, the Hilbert-Huang transform has low resolution and is prone to modal confusion

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Digital down converter-Hilbert-Huang transform based instantaneous frequency measuring method
  • Digital down converter-Hilbert-Huang transform based instantaneous frequency measuring method
  • Digital down converter-Hilbert-Huang transform based instantaneous frequency measuring method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0053]In order to better understand the present invention, the method will be further described below in conjunction with the accompanying drawings and specific examples. The parameter design of the example is as follows: For the input signal:

[0054] y=sin(2π×60t)+sin(2π×44t 1 )+sin(2π×42t 2 )(10)

[0055] where: t 1 ∈(0,t / 2),t 2 ∈(t / 2, t), the waveform is as image 3 shown.

[0056] 1) Carry out digital down-conversion to the signal y, and the oscillating signal generated by the NCO is: x=cos(2π×40t), the oscillating signal of x

[0057] waveform like Figure 4 As shown, then y is multiplied by the signal generated by the NCO, and the signal obtained after low-pass filtering is:

[0058] the y 1 =Asin(2π×20t)+Bsin(2π×4t 1 )+Csin(2π×2t 2 )(11)

[0059] Among them, A, B, and C are constants, which are related to the design of the filter, and the waveform is as follows Figure 5 shown.

[0060] 2) for y 1 Do HHT transformation to get y 1 The instantaneous freque...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention relates to a digital down converter-Hilbert-Huang transform based instantaneous frequency measuring method, applied to the technical filed of radio. The method includes the following steps: 1) an original signal is subject to digital down conversion, and interested signal is converted into zero intermediate frequency; 2) the converted signal is subject to Huang transform, thus obtaining all the single frequency components; 3) each single frequency component signal is subject to Hilbert transform, and instantaneous frequency of the converted signal is solved; 4) the instantaneous frequency of the original signal is recovered according to the instantaneous frequency of the converted signal finally. The invention not only can show the advantage that the traditional Hilbert-Huang transform (HHT) can realize linearization and stabilization of non-linear and non-stationary signal, but also well overcomes frequency aliasing of the traditional HHT transform and shows higher frequency resolution. The invention is verified in a designed hardware system, and the algorithm can carry out effectively real-time estimation on frequency.

Description

technical field [0001] The invention relates to a method in the field of radio technology, in particular to an instantaneous frequency measurement method based on digital down-conversion-Hilbert-Huang transform. Background technique [0002] The analysis of non-stationary signals has been paid more and more attention by people. For non-stationary signals, in order to reflect the law of frequency spectrum changing with time, people put forward the time-frequency joint analysis method, that is, the one-dimensional time signal is converted into two-dimensional time-frequency density Represented in functional form, it aims to reveal how many frequency components are contained in the signal and how each component changes with time. There are many time-frequency analysis methods, such as short-time Fourier transform (STFT), Wegener-Willi distribution (WVD), wavelet transform (WT), Hilbert-Huang change, etc., although these methods are not suitable for non-stationary signals Howev...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/02G01R23/165
Inventor 王海范文晶宣宗强孟繁杰周增建王召利
Owner XIDIAN UNIV
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap