# 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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### Proof of bedrosian theorem

I was looking for a straightforward proof for Bedrosian's identiy (or theorem) which says the Hilbert transform of the baseband signal times the passband signal is the original baseband signal times ...
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### Implementation of Hilbert Spectrum in MATLAB

I am trying to implement this equation on Matlab, where i have wj values in the form of an array, cumtrapz command of MATLAB implements this, but its confusing which way is exact. such as cumtrapz(t,...
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### 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 ...
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 ...
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### 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 ...
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### Meaning of Hilbert Transform

I understand the Fourier Transform which is a mathematical operation that lets you see the frequency content of a given signal. But now, in my comm. course, the professor introduced the Hilbert ...
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### 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 ...
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 ...
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### Obtain I/Q Components from a Real Signal On the Fly - Hilbert Transform or Digital Downconversion?

I'm planning to build a data acquisition system for a software-defined radio receiver. Basically, it just uses an ADC which samples an analog signal and send the signal to a processor. And then a ...
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### Negative instantaneous frequency with hilbert transform using scipy hilbert

When I produce a chirp signal with a duration of 2 sec, sampling frequency of 200Hz, with frequencies ranging from 20Hz-100Hz, I get negative instantaneous frequencies using the scipy(Python) Hilbert ...
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### 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 ...
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### Validity of an argument that two transfer functions are minimum-phase based on their ratio being minimum-phase

Update I think the essence of my question below is this: If the ratio of two transfer functions may be represented exactly as a minimum-phase filter (MPF) plus a pure delay (in the title, I simply ...
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### Design causal FIR filter to approximate hilbert transform

I'm attempting to design an FIR filter that approximates the Hilbert transform in order to get a $90^{\circ}$ phase shift and unity gain. However, I'm having trouble adjusting the filter to make it ...
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### 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 ...
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### 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 ...
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### Why does Hilbert filter distorts the shape of the signal?

If all the harmonics composing a the signal are shifted by the same amount, this would be the same as sampling later or earlier in time. I think. Take a simple pulse train as an example. If Fourier ...
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### Effects of interchanging sine terms with cosine terms

Suppose we have a real signal $x(t)$. Now, we know that $x(t)$ can be represented as a sum of sines and cosines. w be the angular frequency. If $a(\omega)$ be the coefficients of the cosine terms, ...
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### Discrepancies between FFT-based Hilbert Transform and FIR filter results

I compared the results of Hilbert Transform as provided in scipy.signal.hilbert() (which is uses I/FFT as you can see in the source code) with its approximation implemented as FIR filter using coeffs ...
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### 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....
146 views

### Not able to reach minimum phase using Hilbert transform

My problem is pretty simple, I've designed a magnitude response and I would like to find the corresponding minimum phase filter. I'm using the code below and unless there is a bug my eyes don't want ...
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### 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 (...
128 views

### Difference between Analog IQ sampling and creating IQ digitally

In the context of wideband receiver design, what are the advantages and disadvantages of Analog IQ sampling vs creating IQ digitally (with Hilbert transform)? Why do we use different ADCs to create ...
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### 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 ...
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### 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 ...
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### Relation between Fourier phase and Analytic Signal Phase

Do you know if there is a relation between the phase of the Fourier Transform and the phase of the Analytic signal? I mean, if i have a signal s(t) then... ...
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....
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### 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 (...
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### Something like Hilbert Transform to obtain arbitrary Phase Shift? [duplicate]

I was wondering if there is something like a Hilbert Transform but that can implement an arbitrary phase shift to every frequency component. I mean, I know that the magnitude response of a "...
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### Is there any practical application for performing a double Fourier transform? …or an inverse Fourier transform on a time-domain input?

In mathematics you can take the double derivative, or double integral of a function. There are many cases where performing a double derivative models a practical real-world situation, like finding the ...
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### 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 ...
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### Hilbert transform in the frequency domain

As I know, the Hilbert transform $$H(x(t))=\frac{1}{\pi t}\star x(t)$$ in time domain is equal to $$-j \operatorname{sgn}(f) \cdot X(f)$$ in frequency domain. so I tried simple example using ...
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### Magnitude of the analytic signal

It's well known that magnitude of the analytic signal for narrowband signals gives the envelope. For example we can demodulate AM signal by abs(hilbert(s_AM)) in ...
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### How to handle edge effects with EMD (HHT)?

In the application of the Huang Hilbert Transform (HHT) (or aka EMD, Empirical Mode Decomposition), there is the notable challenge of handling the edges (boundaries) of the signals; as noted in the ...
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### 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 ...
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### 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 ...
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### IIR Hilbert Transformer

I'm beginning to explore discrete Hilbert transformers - ways to achieve 90°. phase shift across a band of perhaps 6 kHz at a 44.1 kHz sampling rate. I'm trying to stick with IIR filters in order to ...
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### Noise sensitivity of the (classical) Empirical Mode Decomposition routine

I tried to apply a MATLAB Empirical Mode Decomposition routine to denoise a signal, basically retaining only the last IMFs, with a criterion based on the mode energy. To validate the routine, I have ...
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### 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 ...
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### Pre-envelope of an FM signal $s(t) = A\cos[\omega_ct + B\sin(\omega_xt)]$ [duplicate]

I want to ask a question about pre-envelope of an FM wave: $$s(t) = A\cos[\omega_ct + B\sin(\omega_xt)]$$ Can someone explain briefly how we calculate the pre-envelope of this signal?
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### Question about Hilbert transform of a cosine signal

In the paper entitled "On instantaneous frequency", it is claimed that the Hilbert transform of a signal in the form of $A(t)cos(\phi(t))$ would result in $A(t)sin(\phi(t))$, where $A(t)$ is ...
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### Question about Hilbert transform

Hilbert transform of a function $g(t)$ which is defined in time domain, would result in another function in time domain. Is there any other transformation like Hilbert that the results be in time ...
### Is $H\left\{x_h(t)\right\} = H\left\{x\left(t-\frac{\pi}{2w_c}\right)\right\}$ where $H$ is Hilbert transform
Accordind to my understanding of the following: $$H\left\{X(f)\right\} = -j\;sgn(f)\; X(f) \qquad(1)$$ my work so far: since $x_h(t) = x\left(t-\frac{\pi}{2w_c}\right)$, Their Hilbert ...