# Questions tagged [hilbert-transform]

Hilbert Transform is an operator of a function of time or frequency domain that, unlike the Fourier Transform, returns a function in the same domain. The Hilbert Transform of $x \left( t \right)$ essentially preserves magnitude and shifts the phase of all positive frequency components by -90° (Also shifts the phase of all negative frequencies by +90°).

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1answer
76 views

### IQ demodulation from specific rate

We have an acquisition hardware in our lab that acquires and digitizes data from a source generating band-limited signal in the MHz range. It samples the signal at a rate of 4 times the center ...
1answer
133 views

### BER based transmitter gain

Are there any direct relation formula between BER and Transmitter gain. The higher the transmitter gain is, the better the BER performance is. In here, I want to plot graph for the BER based on ...
0answers
391 views

### Complex bandpass filter giving quadrature signal

I have found a technique detailed on page 34 & 35 of this thesis. In this, the author states a complex bandpass filter can be derived by first making a prototype real valued IIR filter, then ...
1answer
592 views

### Instantaneous Frequency Estimation by Hilbert Transform - Theoretical Justification and Proof

I would like to better understand why the instantaneous frequency estimation by Hilbert transformation works (and especially why it doesn't work / lead to precise results in many cases). The ...
1answer
143 views

### Non-Linear, Non-Stationary spectral analysis methods! When and where?

I have been reading about non-linear non-stationary signal analysis methods and it seems to do this type of analysis the go-to method is the Empirical Mode Decomposition (EMD), then Hilbert Transform (...
0answers
664 views

### real refractive index from Kramers Kronig relation

I have a measurement of the complex part of the refractive index $k$ (where the refractive index is $m = n + i\,k$) measured at a nonlinear grid of wavelengths or frequencies that span several orders ...
0answers
367 views

### Connections between quantum field theory and signal processing

I've been working with quantum field theory on the basis of it being a stochastic signal processing formalism for a number of years. The projection to fourier components within the forward light-cone ...
0answers
663 views

### Hilbert Transform, filters - two different phase graphs

Relationship between magnitude response and phase response for minimum phase is: Phase plots are obtained from Hilbert transform of real magnitude values. Input to Hilbert transform was a vector (...
1answer
227 views

### Does the instantaneous frequency contradict the uncertainty principle?

The uncertainty principle states that there is a trade off between time and frequency. So, finding frequency components at specific time is impossible. However, the instantaneous frequency measure the ...
1answer
53 views

### minimum-phase phase via Hilbert transform returned values

Following my previous question: HRIR Minimum phase I managed to compute the minimum-phase phase of a FIR filter (in my particular case, HRTF filters). However I am not sure of the phase values ...
2answers
67 views

### Obtain Envelope and Pitch curves of my Singing Voice

I wish, in real time, to hum into a mic and produce via dsp the envelope and pitch of what I am humming, before outputting these two signals to my analog synth. This synth takes a gate and a cv signal....
0answers
37 views

### Hilbert Transform on split datastream produces phase flip

this is my first post here! I'm trying to do phase correction on a signal from a linear CCD (2048 pixels, 10bit per pixel, 250kHz linerate) in an FPGA. Therfore I need to generate an analytical ...
0answers
24 views

### How to construct marginal Hilbert spectrum

Suppose $f$ is a signal of duration $t_d$ sampled each $0.01 sec$. After employing empirical mode decomposition (EMD) to $f$, $n$ number of intrinsic mode functions (IMF) would be extracted. Using ...
1answer
118 views

### phase difference detection

For application of syncing sampling clock phase to carrier phase of received signal where the received signal is sampled with 10 times the carrier phase and modulated with the PSK shown in the figure (...
0answers
616 views

### Plotting Hilbert and Marginal Spectra in Python

I am using the PyEMD package for python 3.6. I want to create a 2d plot of hilbert spectrum (x: Time, y: Frequency, Colorbar: Amplitude) and the Marginal Spectrum (x: Frequency, y: Amplitude) I can ...
0answers
55 views

### Discrete Hilbert transform enhancements?

Consider the Discrete Hilbert Transform, which takes a sequence $u[n]$ defined on the interval $-M\leq n\leq M$ and returns the discrete convolution $$\tilde u[n]=\sum_{i=-M}^Mu[i]h[n-i]$$ where the ...
0answers
115 views

### Compute hilbert transform from DCT- FFTW3 REDFT00

My problem is similar to this but not the same. Edit: Here is a description of Neumann boundary conditions for differential equations: Neumann-type boundary conditions means derivatives are ...
0answers
898 views

### Hilbert Huang Transform: Negative value in instantaneous frequency

I'm working on Hilbert Huang Tranform and have a question on computation of instantaneous frequency. I'm using HHT toolbox by Patrick Flandrin for EMD and computing IF manually. Problem is that I am ...
0answers
173 views

### How to get the phase offset from the instantaneous phase

The phase components of a signal that they are got from the Fourier Transform, are simply, the phase offset of each sinusiod. Which is the $\phi$ in equation $1$. However, in case of Hilbert transform,...
0answers
964 views

### Instantaneous power estimation by discrete hilbert transform - how far does it smooth?

In my research area, instantaneous power in a specific frequency band is commonly estimated by the following procedure: Apply a bandpass filter on the raw signal (e.g. 80-90Hz bandpass). Estimate ...
0answers
182 views

### How to get the quaternionic analytic signal of a image?

The 2D discrete image signal's quaternionic fourier transform can be described as F(u,v), and its 2D analytic signal often be described as:  F_q(u,v) = (1 + \mbox{sgn}(u))(1 + \mbox{sgn}(v)) F(u,v) ...
1answer
102 views

### Why does the Hilbert-Huang transform not suffer from the uncertainty principle, and what are the implications of this?

I have been studying the Hilbert-Huang transform, which I understand is a frequency analysis technique that uses the adaptive IMFs basis components to decompose a signal using EMD. I understand that ...
0answers
26 views

### Generation of Aysnchronous signals in matlab

I have to develop the MatLab code for a signal to find how the frequency and amplitude content changes during the phase of its propagation from one place to other. It has to do with Coherency losses ...
0answers
30 views

### Instantaneous amplitude of a constant frequency sine wave?

I am playing around with the Hilbert transform using Python's scipy.signal.hilbert package to better understand what the various instantaneous properties are given different input signals. One input ...
0answers
47 views

### How does the Hilbert Transform extract the in-phase and quadrature phase components of a real passband signal?

I am taking an intro to radar signal processing course and we are discussing the Hilbert Transform and how it take a real input and its output is analytically complex. I'm trying ) how a radar ...
0answers
46 views

### Decoding images from NOAA satellite APT signals

I've been working on a decoder for these APT images for a while now. I started years ago, in Python, and was able to implement a working decoder quickly. A few months ago, I came back to the project ...
0answers
35 views

### Extrapolation of band-limited frequency data

I'm now studying "How to do accurate transform from band-limited frequency data specifically S-parameter data of high speed interconnect to the causal impulse response in time domain. There are ...
0answers
7 views

### Does the EEMD (Ensemble Empricial Mode Decompsition) also reduce the sensitivity to noise?

EEMD (Ensemble Emprical Mode Decomposition) was introduced to improve the problem of mode mixing and mode splitting of the classical EMD (Emprical Mode Decomposition). How much does the EEMD reduce ...
0answers
19 views

### How to I obtain the real part of a an Analytic Signal when the real and imaginary parts have been delayed by different amounts

A real audio signal (0-3 KHz) is processed by a Hilbert filter to obtain the Imaginary component. Both the real signal and the imaginary are delayed but by different amounts. I want to obtain the real ...
1answer
21 views

### Implementing an L-System conversion from R2 to R1 for symmetric, square matrices

I have been reading for some time about L-Systems, and specifically the Hilbert Space filling curve. I am interested in writing a function to convert upper-triangular matrix coordinates into an ...
0answers
13 views

### What is the origin of the line shape in a Marginal Hilbert Spectrum

When calculating the marginal Hilbert spectrum of a discretely sampled harmonic oscillation (sine wave), I have found that the peak in the spectrum has a roughly Lorentzian line shape, albeit ...
0answers
22 views

### Why does the Marginal Hilbert Spectrum of an anharmonic oscillator have two peaks?

I've been looking at the marginal Hilbert Spectra of both the simple harmonic oscillator and the anharmonic Morse oscillator. I have found that while the SHO has a marginal spectrum with a single and ...
0answers
86 views

### Calculating Marginal Hilbert Spectrum across IMFs using mhs() in MATLAB

I'm working on an EEG dataset from which I need to extract the power of five different frequency bands. I'm doing this by performing Hilbert Transform on the ICA activations from performing channel-...
0answers
27 views

### What is the relationship between a signal's Marginal Hilbert Spectrum and Fourier Spectrum?

I am looking at the differences between Marginal Hilbert spectra and Fourier spectra and I was wondering what the mathematical relationship is between them and under what conditions they become ...
1answer
47 views

### Is there a way to break down a signal into its respective phases (4 in this case) to be later analysed individually

Is there a way to extract amplitude information but over 4 phases of the same frequency. That is, if the frequency is known could I extract amplitude peaks (between given values)in the time domain in ...
0answers
27 views

### Phase of complex nonsinusoidal signals

What's the best method for calculating phase of complex nonsinusoidal signals? I've tried using Hilbert transform, but I've found that my results change drastically depending on the amount of data I ...
0answers
43 views

### Bandwidth in the filter-Hilbert method

I understand that the Hilbert transform on broadband data produces uninterpretable results. And so we first bandpass the data, and then run the Hilbert transform. My question is, how wide can the ...
0answers
103 views

### Audio experiment with intermodulation by multiplying two analytic signals

1) First, I describe intended processing with a basic case: Let's say on left channel I have a sin wave with frequency F1, and constant amplitude A1. Then on right channel a sin wave with frequency ...
2answers
194 views

### Phase shift of all-pass bi-quadratic filter

Does anybody know how to derive this phase function for that all-pass filter structure? Many papers re-print them, and corresponding chart as well. But nobody mentions that at normalized frequency 0....
0answers
113 views

### Passband filter before Hilbert transform

I have a .wav file of human speech sampled at 48kHz. Before making the analytic signal with: hilbert(s_real) lets say in range 200 - 3,500 Hz, I probably need to do pass-band filtering, say 300 - 3,...
0answers
4k views

### Hilbert Transform - C or C++ code implementation

For a minimum phase system relationship of magnitude response to phase response is: In the search for C code implementation I have found a ht.c file on www.physionet.org. However, this code specifies ...
0answers
72 views

### What is the relationship between signal and its analytical version?

Hilbert transform is used to transfer signal into analytical signal. But why after the transform, the envelop and instant frequency (if the signal is monogenic) can be calculated. What is happened in ...
1answer
373 views

### Problem executing Hilbert transform on $x$-$y$ plot in MATLAB

I have a wav signal I have imported into MATLAB, and I would like to find its envelope. I want to do this via the Hibert transform. But whenever I try to find the Hilbert transform of the signal I ...