## Re: Complex version of an impulse

Started by in comp.dsp17 years ago

Bergers wrote: ... > We have to be careful with the terms used in describing signals. Analytic > signals and complex (I and Q) signals...

Bergers wrote: ... > We have to be careful with the terms used in describing signals. Analytic > signals and complex (I and Q) signals are not necessarily the same. Reference > pages 58-59 of Radar Detection by DiFranco and Rubin. DiFranco and Rubin define > an analytic signal as y(t) = s(t) + jx(t), > where x(t) is the Hilbert transform of the real signal s(t). The Fourier > transfo

## hilbert transform application

Started by in comp.dsp17 years ago 15 replies

Hello everyone, To begin with I would like to express my gratitude to the countless number of people who have been helping me indirectly over...

Hello everyone, To begin with I would like to express my gratitude to the countless number of people who have been helping me indirectly over the last few months. This is my first post in this group and I am sure I will not be disappointed. I am new to the field of DSP no courses ever taken, but working with it now. I have a data set that has been sampled at a rate of 44khz for a minu...

## Instantaneous frequency recovery using hilbert transform

Started by in comp.dsp17 years ago 1 reply

Hello, I am going to recover the instantaneous frequency f(t) of a chirp signal y(t) using hilbert transform. Here is my MATLAB code: Fs =...

Hello, I am going to recover the instantaneous frequency f(t) of a chirp signal y(t) using hilbert transform. Here is my MATLAB code: Fs = 1000; % Sampling frequency T = 2; % Signal time duration is 2 seconds. t=0:1/Fs:T; f0 = 50; % Initial frequency is 50hz f1 = 100; % f(t) changes from 50hz to 100Hz in 2 seconds. freq = f0 + (f1-f0)...

## Inverse Hilbert Filter

Started by in comp.dsp17 years ago 3 replies

I have a real signal from which I extract an analytic signal by Hilbert filtering. To recover the real signal, I use an inverse Hilbert filter....

I have a real signal from which I extract an analytic signal by Hilbert filtering. To recover the real signal, I use an inverse Hilbert filter. The context of this is for SSB transmission of a real signal and conversion to DSB at the receiver. Connected back to back, the forward and inverse transforms should give almost perfect recovery. However, because the ideal Hilbert filter is infinite i...

## Minimum phase vice versa minimum phase

Started by in comp.dsp17 years ago 10 replies

Hello, I'm actually confused with minimum phase. I know actually two applications for minimum phase: 1. A FIR filter is designed and the...

Hello, I'm actually confused with minimum phase. I know actually two applications for minimum phase: 1. A FIR filter is designed and the result typically is a time domain signal (or taps) with a symmetric structure = linear phase This filter can be converted to a minimum phase filter e.g. by methods described at dspguru. So for example Hilbert transforms are often used. If I do a FFT t...

## Hilbert transform and SSB power??

Started by in comp.dsp17 years ago 1 reply

I have a question on the power of SSB (Single side band) AM. if transmitted signal is expressed as: u(t)=Ac*m(t)*cos(2pi*fc*t) plus minus...

I have a question on the power of SSB (Single side band) AM. if transmitted signal is expressed as: u(t)=Ac*m(t)*cos(2pi*fc*t) plus minus Ac*H[m(t)]*sin(2*pi*fc*t), Ac=carrier amplitude, fc=carrier frequency, m(t)=message signal, and H[m(t)] is Hilbert transform of m(t). What is the equation for received power (Pr) in terms of power of message signal (Pm)? Some books say Pr=[(Ac^2)...

## Re: Hilbert transform and SSB power??

Started by in comp.dsp17 years ago

Bob wrote: > I have a question on the power of SSB (Single side band) AM. > > if transmitted signal is expressed as: > > ...

Bob wrote: > I have a question on the power of SSB (Single side band) AM. > > if transmitted signal is expressed as: > > u(t)=Ac*m(t)*cos(2pi*fc*t) plus minus Ac*H[m(t)]*sin(2*pi*fc*t), > > Ac=carrier amplitude, fc=carrier frequency, m(t)=message signal, and > H[m(t)] is Hilbert transform of m(t). What is the equation for > received power (Pr) in terms of power of message signal (P

## filtering in freq domain

Started by in comp.dsp17 years ago 15 replies

Hi all, To begin with thanks to all those who have made this wonderful group. I am a mechanical engineer working on hilbert transforms. I...

Hi all, To begin with thanks to all those who have made this wonderful group. I am a mechanical engineer working on hilbert transforms. I have a time domain signal sampled at 2100pts/sec for 60secs and has signals at 3 freqs. I do a fft, get into my freq domain and then filter all freq except the freq of interest. My question is a) What is the best way to filter in freq domain. I...

## Hilbert transform to calculate Magnitude from Phase?

Started by in comp.dsp17 years ago 14 replies

I've seen how to do the opposite (get phase response from a bandlimited magnitude response). Can the opposite be done? If so, what is...

I've seen how to do the opposite (get phase response from a bandlimited magnitude response). Can the opposite be done? If so, what is the algorithm? thanks

## changer voice

Started by in comp.dsp16 years ago 1 reply

How to change voice (disguise) without formant, pitch analysis,etc, using only simple common DSP method as Hilbert transform and...

How to change voice (disguise) without formant, pitch analysis,etc, using only simple common DSP method as Hilbert transform and forth. Unfortunetly I have some mips only. Maybe this problem hasn't decision in these circumstances ?

## FFT and Hilbert

Started by in comp.dsp16 years ago 2 replies

Hi Folks, I am having problems trying to understand why would you apply a Hilbert Transform after a FFT i.e. X(f)XH(f) where H denotes...

Hi Folks, I am having problems trying to understand why would you apply a Hilbert Transform after a FFT i.e. X(f)XH(f) where H denotes the Hilbert transform. What are the benefits for doing this? Cheers Paul

## Hilbert Transform

Started by in comp.dsp16 years ago 3 replies

I'm looking for an introductory article on the theory of the Hilbert transform. Anyone know of a good reference? This message was sent...

I'm looking for an introductory article on the theory of the Hilbert transform. Anyone know of a good reference? This message was sent using the Comp.DSP web interface on www.DSPRelated.com

## 90 degrees phase shift

Started by in comp.dsp16 years ago 24 replies

Hi, I'm an hold analog engineer , actually developing a DSP based application and I need to change of 90 degrees the phase of a signal on the...

Hi, I'm an hold analog engineer , actually developing a DSP based application and I need to change of 90 degrees the phase of a signal on the range of 50 - 250 Hz aving the system a 200uSec sampling rate. I have considered the Hilbert FIR filter but for the moment I cannot get it to work not even reducing the sampling rate. In particular I nedd to phase shift by 90 degrees a signal (voltage)...

## Disperately seeking Hilbert filter coefficients

Started by in comp.dsp16 years ago 11 replies

Hi everybody thanks to the support I received on a previous post I have been able to get working my implementation of a 90 degrees phase...

Hi everybody thanks to the support I received on a previous post I have been able to get working my implementation of a 90 degrees phase shifter, all I need now is a good guy which can calculate and post for me the coefficients for a 67 order Hilbert with Hamming windowing, because my tool just reach 35, or some reference to a free tool on the net for this job. ( I'm not planning to buy a 1K...

## Software Pulse Amplitude Demodulation

Started by in comp.dsp16 years ago 2 replies

Hi all, I am doing a simple demodulation of a sampled RF signal. I set my digitizer at a fixed 1 GS/s. I don't know what my carrier will be,...

Hi all, I am doing a simple demodulation of a sampled RF signal. I set my digitizer at a fixed 1 GS/s. I don't know what my carrier will be, but it will be less that 200MHz. The signal is pulse amplitude modulated, and I want to recover the original signal. To do this, I have applied a Hilbert transform, and then derived the magnitude which gives me a good approximation of the encoded signa...

## Envelope Detector using Hilbert Transform

Started by in comp.dsp16 years ago 7 replies

All I have been kind going through previous threads in this group on similar concern and question that I have. Still I feel my feet is not on...

All I have been kind going through previous threads in this group on similar concern and question that I have. Still I feel my feet is not on the ground yet...with this issue.. Background: I have working with ultrasound signals (300 Khz) from a solid state sensor to a target at 3". The received signals from the sensor (300 Khz) are digitized through a sampling card and imported into MATLAB,...

## Hilbert transform using FFT approach

Started by in comp.dsp16 years ago 48 replies

Hi All.. 1. As MATLAB uses the FFT approach computing the hilbert transform of the signal, is this approach suitable for real time...

Hi All.. 1. As MATLAB uses the FFT approach computing the hilbert transform of the signal, is this approach suitable for real time implementation on a SHARC or TI DSP. ? 2. Can somebody point out some good references for real time implementation of Hilbert transform. Thanks Paul This message was sent using the Comp.DSP web interface on www.DSPRelated.com

## LTI systems? (non-HW non-test questions...)

Started by in comp.dsp16 years ago 6 replies

Hi all, Is a Foureir Transformer an LTI system? (input x(t), output the foureir transform of the input x(t)) Is a Hilbert Transformer...

Hi all, Is a Foureir Transformer an LTI system? (input x(t), output the foureir transform of the input x(t)) Is a Hilbert Transformer an LTI system? (input x(t), output the hilbert transform of the input x(t)) are these systems stable? Thanks a lot!

## Alternative to Hilbert Transform

Started by in comp.dsp16 years ago 4 replies

I am analysing data from an optical velocimetry probe (PDV) using FFTs and Hilbert transforms. The signal is a varying frequency sinusoid embedded...

I am analysing data from an optical velocimetry probe (PDV) using FFTs and Hilbert transforms. The signal is a varying frequency sinusoid embedded in a noisy background - with a quasi DC baseline that may also vary more slowly with time. I have had good luck using FFT based spectrogram techniques (with high and low pass filters where appropriate) to extract a weak S/N sinusoid, or multiple freq...

## Applying hilbert transform close to DC

Started by in comp.dsp16 years ago 9 replies

Hello, I've been trying to apply a hilbert transform from DC to around 10kHz @ a 57600Hz sample rate however the 90 degree phase shift doesn't...

Hello, I've been trying to apply a hilbert transform from DC to around 10kHz @ a 57600Hz sample rate however the 90 degree phase shift doesn't work well close to DC (which is expected). Btw, this is for an implementation of the phasing method for SSB-SC modulation. Is there some way to get around this problem? or a better way to perform the phase shift? I've been experimenting with up...