## Hilbert transform of a sine wave is an inverted cos wave, right?

Started by in comp.dsp14 years ago 8 replies

The Hilbert transform of a sine wave is an inverted cos wave, right?

The Hilbert transform of a sine wave is an inverted cos wave, right?

## Calculating instantaneous phase of a simple signal

Started by in comp.dsp14 years ago 40 replies

OK, say I have the signal: signal=(sin(2*%pi*77.7811 .* x) + .39*sin(2*%pi*74.7811 .* x) + .34*sin(2*%pi*81.3811 .* x)); From this I know:...

OK, say I have the signal: signal=(sin(2*%pi*77.7811 .* x) + .39*sin(2*%pi*74.7811 .* x) + .34*sin(2*%pi*81.3811 .* x)); From this I know: the real part of the signal is identical to the signal, and the imaginary part is: Q = (-cos(2*%pi*77.7811 .* x) - .39*cos(2*%pi*74.7811 .* x) - .34*cos(2*%pi*81.3811 .* x)); Since the Hilbert transform of a sin(x) = -cos(x). Using this, I can...

## Demodulating QPSK

Started by in comp.dsp13 years ago 49 replies

Is it possible forego the joys of the Costas loop and demodulate a scalar QPSK signal using a bandpass filter, a Hilbert transformer and the...

Is it possible forego the joys of the Costas loop and demodulate a scalar QPSK signal using a bandpass filter, a Hilbert transformer and the atan2(im,re) function?

## Discrete Real Hilbert function

Started by in comp.dsp13 years ago 4 replies

I was just working on my thesis project, in which I have to make a convolution between two discrete real signals (one is the signal to...

I was just working on my thesis project, in which I have to make a convolution between two discrete real signals (one is the signal to be transformed, and tho other the Hilbert function), in order to get the Hilbert Transform. The thing is that I have two arrays of real signals, and I have to make the convolution. One array contains the signal (this signal contains real values in each position)...

## Hilbert Transform code

Started by in comp.dsp13 years ago 11 replies

I'm trying to separate a data signal of ~800Hz from a carrier wave which is ~2000Hz. As both frequencies vary slightly over time I was hoping to...

I'm trying to separate a data signal of ~800Hz from a carrier wave which is ~2000Hz. As both frequencies vary slightly over time I was hoping to use envelope detection to strip off the carrier, my sample rate is 22560. I've read about taking the Hilbert transform of the input signal and then squaring this and adding it to the square of the input signal, before finally taking a square root of t...

## constant 90-degree phase shift using parallel allpass filter networks

Started by in comp.dsp13 years ago 15 replies

One method of creating a quadrature signal is to pass an input signal through two parallel allpass networks, where the outputs of the...

One method of creating a quadrature signal is to pass an input signal through two parallel allpass networks, where the outputs of the two networks differ in phase by 90 degrees. Each allpass network is typically high-order to obtain reasonable accuracy in terms of holding the phase difference over frequency. One advantage of this technique compared with the more usual anti-symmetric Hilbert f...

Started by in comp.dsp13 years ago 8 replies

hi everyone, million thanks in advance...i would like to know about EMD which is part one of hilbert huang transform. the procedure of EMD is...

hi everyone, million thanks in advance...i would like to know about EMD which is part one of hilbert huang transform. the procedure of EMD is : 1)For a signal X(t), let m1 be the mean of its upper and lower envelopes as determined from a cubic-spline interpolation of local maxima and minima. The locality is determined by an arbitrary parameter; the calculation time and the effectiveness of the ...

## Using Z-transform with continous time signals

Started by in comp.dsp13 years ago 23 replies

Hello, can we use Z-transform on continuous time signals to find their z-domain analysis. (what do we really realize in z-domain and how is it...

Hello, can we use Z-transform on continuous time signals to find their z-domain analysis. (what do we really realize in z-domain and how is it different from frequency domain analysis) and also can we use Laplace for discrete time signals. Also what kind of analysis/information can we get from i) Laplace Transform ii) Z Transform iii) Fourier Transform iv) Hilbert Transform (PS. n...

## negative frequency and Hilbert transform

Started by in comp.dsp13 years ago 3 replies

hello forum, I might need some help understanding the usefulness of the complex analytic signal. What we measure are real valued signals...

hello forum, I might need some help understanding the usefulness of the complex analytic signal. What we measure are real valued signals whose Fourier transform can be one-sided, or, if we used complex sinusoids, two-sided and symmetric. Then the real signal is made of positive and negative frequencies in equal amount. The negative sinusoids dont really a physical meaning, I guess. Comple...

## enforce minimum phase using hilbert transform

Started by in comp.dsp13 years ago 1 reply

Hello group, I have a question regarding minimum phase system and causal enforcement. For a minimum phase system, the measured discrete...

Hello group, I have a question regarding minimum phase system and causal enforcement. For a minimum phase system, the measured discrete frequency domain data are given. To remove the measurement noise, I use the -hilbert(log(abs(H(F))) to generate the phase of the system, and then get time domain waveform through h(t) = IFFT(abs(H(F))* exp(j*phi(F))). I found h(t) is not causal. From the t...

## Impulse response of the hilbert transform

Started by in comp.dsp12 years ago 1 reply

hi there, i was going through a paper on using hilbert transform for edge detection in image processing.It said over there that the hilbert...

hi there, i was going through a paper on using hilbert transform for edge detection in image processing.It said over there that the hilbert transform works better than differentiation for edge detection as it has longer impulse response which helps reduce the effect of noise.I am new to the subject and dont understand what exactly does a longer impulse response mean.??.and how does the impulse res...

## Hilbert-Huang Transformation

Started by in comp.dsp12 years ago 10 replies

Anyone heard of it? Is it the next best thing since sliced bread and the Fourier Transform? I just discovered it and it seems to have some...

Anyone heard of it? Is it the next best thing since sliced bread and the Fourier Transform? I just discovered it and it seems to have some interesting potential... "The HHT technology is a highly efficient, adaptive, and user-friendly set of algorithms capable of analyzing time-varying processes. Designed specifically for nonlinear and nonstationary signals, HHT can be used to analyze ...

## Any one can explain the Hilbert transform related question for me?

Started by in comp.dsp12 years ago 2 replies

Hi, I read a paragraph of "Theory and application of digital signal processing" of L. R. Rabiner on page 70. It says: For v(n), a...

Hi, I read a paragraph of "Theory and application of digital signal processing" of L. R. Rabiner on page 70. It says: For v(n), a Hiltert transformed signal, its Fourier transform V(e^ (jw)) has the property V(e^(jw))=0 pi < w

## Hilbert Transform Problem

Started by in comp.dsp12 years ago 4 replies

Dear All, I have a question regarding hilbert transformer. If i take the bandpass signal and sample it it would be real. Now when i multiply...

Dear All, I have a question regarding hilbert transformer. If i take the bandpass signal and sample it it would be real. Now when i multiply it with a complex exponential to downconvert it I get a complex baseband signal. On the other hand, if i take the bandpass signal, pass it through a hilbert transformer and get a complex signal, and then downconvert using complex multiplication i get di...

## Using Hilbert-Huang transfor in audio?!

Started by in comp.dsp12 years ago 1 reply

Dear all, As I know, the Hilbert-Huang transform (HHT) (http://techtransfer.gsfc.nasa.gov/HHT/) is a powerfull tool declared by NASA. Compared...

Dear all, As I know, the Hilbert-Huang transform (HHT) (http://techtransfer.gsfc.nasa.gov/HHT/) is a powerfull tool declared by NASA. Compared to Fourier transform (FFT), HHT is capable of analyzing time-varying processes, nonlinear & nonstationary signals that are in a real world. It seems to be interesting if we can use it in audio signal processing like identification, noise cancellation......

## Complex Data/ Complex Noise Simulation

Started by in comp.dsp12 years ago 1 reply

I have a data set that is complex that i generated by using a hilbert transform. I wanted to add guassian noise (complex) to the data and then...

I have a data set that is complex that i generated by using a hilbert transform. I wanted to add guassian noise (complex) to the data and then do some processing. When i do this, is the correct method to add the hilbert tranform of the data to the hilbert transform of the noise? Or do i use a 'different' noise sequence and create complex additive noise to keep the I and Q of the noise uncorrela...

## IIR Hilbert - Matlab help anyone

Started by in comp.dsp12 years ago 9 replies

Hi, I'm (trying to) implement an IIR Hilbert Transformer. I found a reference to a design which provides the z domain poles and zeros...

Hi, I'm (trying to) implement an IIR Hilbert Transformer. I found a reference to a design which provides the z domain poles and zeros as listed at the bottom of this post. The function is 12th order and I figured that I could implement this conveniently with 6 cascaded biquads (which I happen to have available in my FPGA DSP design). I calculated out the IIR filter coeffs by taking the c...

## HILBERT HUANG TRANSFORM

Started by in comp.dsp12 years ago 3 replies

hi I've a doubt whether there is any possibility to implement HHT on hardware.Whether it can be implemented on FPGA.Thanks in advance

hi I've a doubt whether there is any possibility to implement HHT on hardware.Whether it can be implemented on FPGA.Thanks in advance

## HILBERT HUANG TRANSFORM

Started by in comp.dsp12 years ago

sir I've tried simulating the program in mathlab and got satisfying results.I 've little knowledge in verilog is there is any way to convert the...

sir I've tried simulating the program in mathlab and got satisfying results.I 've little knowledge in verilog is there is any way to convert the mathlab code into hdl code so that i can use.is there is any sites or books which gives necessary for implementing on fpga for HILBERT HUANG TRANSFORM

## Inverse of Hilbert transform

Started by in comp.dsp12 years ago 7 replies

Hi, I need to extract the envelope of an audio signal and do some changes in its spectum of magnitude, and then I need to reconstruct the...

Hi, I need to extract the envelope of an audio signal and do some changes in its spectum of magnitude, and then I need to reconstruct the signal and take it to the time domain. I thing thatt I can do that taking the hilbert transform of the original signal, find the magnitu and perform the changes; but what i do not know is how to go back to the time domain. How to take the inverse of the hi...