Started by in comp.dsp16 years ago 11 replies

Hi, I would like to ask this simple question, how can I get the complex value in DSP. when I read the sumation of complex value i got only real...

Hi, I would like to ask this simple question, how can I get the complex value in DSP. when I read the sumation of complex value i got only real value. Any help. Example: x[i].re=2; x[i].im=3; I got x2[i]=5 not 2+3i so how can I get the complex value. Thanks

## complex lms

Started by in comp.dsp20 years ago 1 reply

when doing subband, you get the signal in complex value, and you do lms in complex value, when you reconstruct the complex e back to full-band...

when doing subband, you get the signal in complex value, and you do lms in complex value, when you reconstruct the complex e back to full-band e, how will you get real value back? or just take magnitude? Lee

## Levinson algo. wtih complex coef. required

Started by in comp.dsp20 years ago 7 replies

Hi, I am desperatly looking for a generalized Levinson algorithm that can cope with complex autocorrelation values and giving complex filter...

Hi, I am desperatly looking for a generalized Levinson algorithm that can cope with complex autocorrelation values and giving complex filter coefficients... I would like to implement it in C, and i have only found the classical LPC analysis but it can not deal with complex coefficients... Anyone can help ? Thanks in advance

## Complex versus real numbers

Started by in comp.dsp14 years ago 54 replies

I repeatedly come across objections to using complex numbers for DSP. I wonder if there is a good way that I can explain without...

I repeatedly come across objections to using complex numbers for DSP. I wonder if there is a good way that I can explain without struggling? The current case concerns ultrasound, where the measurement is of pressure (on a transducer). My processing uses complex numbers, which naturally arise when I demodulate the signal. The question I am asked is, why are complex numbers necessary when the...

## Complex array Multiplications

Started by in comp.dsp16 years ago 3 replies

Hello every one I am using Microsoft Visual C++6.0 and i needed to multiply a complex data matrix with complex data vectors. Main problem is...

Hello every one I am using Microsoft Visual C++6.0 and i needed to multiply a complex data matrix with complex data vectors. Main problem is large computation time involved in these multiplications (Currently i am treating both real and imaginary parts separately). Kindly tell me is there any library in MS VC++6 for complex numbers ?, since i could not find it in my MSVC package.And can I dow...

Started by in comp.dsp15 years ago 10 replies

Hi all, I have a signal a+jb generated inside DSP. Now, I want to feed the signal to a quadrature modulator, upconvert it to 100MHz and measure...

Hi all, I have a signal a+jb generated inside DSP. Now, I want to feed the signal to a quadrature modulator, upconvert it to 100MHz and measure it with a spectrum analyzer or scope. My question is, the signal a+jb is complex, the quadrature upconversion is also complex, exp(j*2*pi*100e6). Will I see the complex signal, (a+jb)*exp(j*2*pi*100e6) on the spectrum? Also, for the complex sign...

## complex notation

Started by in comp.dsp11 years ago 22 replies

Sirs, I have few questions wrt to complex numbers. 1) I would like to know the main purpose of using complex numbers. 2) I would like to...

Sirs, I have few questions wrt to complex numbers. 1) I would like to know the main purpose of using complex numbers. 2) I would like to know given a number in complex notation, is it possible to convert this into a real number. Thanks, Manish

## Real vs. Complex

Started by in comp.dsp17 years ago 2 replies

I have a question about real and complex numbers. I want to plot the phase and magnitude of a signal that will chirp in frequency from 10MHz to...

I have a question about real and complex numbers. I want to plot the phase and magnitude of a signal that will chirp in frequency from 10MHz to 30MHz. I really want to do more than this, but I think this can easily explain my problem. This can be done in Matlab with no problem, using a complex signal. However in the real world I don't have a complex value, just a real value sampled from a...

## Practical use of Gold Codes

Started by in comp.dsp16 years ago 10 replies

Hi all, I'm planning to use Gold Codes in a DSSS Modem. The question is: The input data is complex but a gold code is not complex....

Hi all, I'm planning to use Gold Codes in a DSSS Modem. The question is: The input data is complex but a gold code is not complex. When spreading the complex data, do you simply set the imag part of the gold code to 0 and do a complex multiplication with the complex input data and again the same when despreading the data? Thanks for any suggestions, Jaco

## complex conjugate

Started by in comp.dsp8 years ago 3 replies

Hello All, Conceptually I understand complex conjugate but what is the application of complex conjugates? Thanks in advance...

Hello All, Conceptually I understand complex conjugate but what is the application of complex conjugates? Thanks in advance ... --------------------------------------- Posted through http://www.DSPRelated.com

## Complex Number tutorial

Started by in comp.dsp11 years ago 27 replies

Hi, I have begun a complex number tutorial which shows how e^jwt works. It is...

Hi, I have begun a complex number tutorial which shows how e^jwt works. It is located: http://fourier-series.com/fourierseries2/complex_tutorial.html I have more work to do on this, but come take a look. I created these programs for complex numbers in order to explain the complex representaion of the fourier series. Brent

## Complex FIR coefficients

Started by in comp.dsp14 years ago 22 replies

What is the physical significance of having an impulse response with complex coefficients ie {h0,h1,h2...hn} where the h values are...

What is the physical significance of having an impulse response with complex coefficients ie {h0,h1,h2...hn} where the h values are complex. Hardy

## Complex FIR Filters

Started by in comp.dsp17 years ago

Hello DSPers, After reading the thread about "Why cplex filters" a question comes to mind: how to generate complex filter coefficients if i do...

Hello DSPers, After reading the thread about "Why cplex filters" a question comes to mind: how to generate complex filter coefficients if i do not wish to apply desired phase and amplitude correction to the original signal? I've passed the initial real signal through a Hilber Transformer, and have thus a complex analytic signal. I'm using a Blackfin DSP, and it has a complex fir function, as...

## Complex filters

Started by in comp.dsp20 years ago 3 replies

Hi all, What is the significance of complex FIR filters used? In general the inputs are the sequences of real values, then where can the...

Hi all, What is the significance of complex FIR filters used? In general the inputs are the sequences of real values, then where can the complex filters be used? If they are used for real inputs, then how do we interpret the complex outputs? Regards, Ishtiaq.

## Complex Data/ Complex Noise Simulation

Started by in comp.dsp14 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...

## sinusoidal signals using complex conjugate exponentials

Started by in comp.dsp10 years ago 15 replies

Sirs, I would like to get a clarification on expressing cosine using complex exponentials ... It is given in texts that A * cos (pi) = A/2 *...

Sirs, I would like to get a clarification on expressing cosine using complex exponentials ... It is given in texts that A * cos (pi) = A/2 * exp pow j * A/2 * pi + exp pow -(j * pi) When I plot the above two complex exponentials, I get 2 points on the complex plane but how these correspond to a single point of cosine signal, I am unable to get. And, how thesd eventually give a cosine sign...

## complex convolution

Started by in comp.dsp19 years ago 3 replies

Dear All, I would like to convolve two complex sequences. Could anybody help me how to define the convolution of two complex sequences...

Dear All, I would like to convolve two complex sequences. Could anybody help me how to define the convolution of two complex sequences please? Thanks in advanced. Regard, nmaedewi This message was sent using the Comp.DSP web interface on www.DSPRelated.com

## Equalizer

Started by in comp.dsp16 years ago 13 replies

I have two complex signals (Input and output) of a channel I need to equalize. I can have 2 linear equalizers one for the real part and one for...

I have two complex signals (Input and output) of a channel I need to equalize. I can have 2 linear equalizers one for the real part and one for the imaginary and train them independently or I can use one complex equalizer and train it using the complex signal. My questions are which one is better? Is there any advantage of one on the other or they are equivalent ? Regards Tom ...

## getting freqz from fft (complex numbers)

Started by in comp.dsp18 years ago 9 replies

After FFT is done, result is array filled with complex numbers. What is the best way to obtain maximum signal amplitudes at corresponding...

After FFT is done, result is array filled with complex numbers. What is the best way to obtain maximum signal amplitudes at corresponding frequencies, maybe even (if possible?) without calculating roots (complex modules) in order to use as less computational resources as possible? thanx in advance, Zlatko

## Filterting a complex sequence

Started by in comp.dsp16 years ago 3 replies

I have a complex sequence with 1 million elements. I have filter five low pass filter coefficients a and b respectively. To filter the complex...

I have a complex sequence with 1 million elements. I have filter five low pass filter coefficients a and b respectively. To filter the complex sequence X - in matlab I execute the filter function. So now: xtd = filter (b,a, X); At issue: I'm having difficulty achieving the same result when I 'break' the complex sequence X in 4 sequences. In other words, I take N elements ( 1 million...