Hi, everyone! I use TMS320c6713 DSP. I compared result of complex fft library in TI DSP with result of complex fft in Matlab. Those waveform...

Hi, everyone! I use TMS320c6713 DSP. I compared result of complex fft library in TI DSP with result of complex fft in Matlab. Those waveform in frequency domain are similar, but exactly not matched. It means.. Range of result in DSP library is wider than one in Matlab. Why? Regards.

Hi comp.dps, I have a baseband complex signal ( i & q ). I want to transmit it somehow, meaning that I have to modulate it in a...

Hi comp.dps, I have a baseband complex signal ( i & q ). I want to transmit it somehow, meaning that I have to modulate it in a carrier ( s(t) = i(t)*cos(wt) + q(t)*sin(wt) ). What if I still want it to be in baseband ( but a transmitable real value, not a complex value ) ? Would a s(t) = i(t) * cos( 0*t ) + q(t)*sin( 0*t ) = i(t) be still valid, containing all the inform...

Hi All, I'm trying to get code together that calculates the complex cepstrum of a waveform. I want to be able to use the cepstral analysis both...

Hi All, I'm trying to get code together that calculates the complex cepstrum of a waveform. I want to be able to use the cepstral analysis both as input to a database, and to be able to re-constitute the waveform using inverted complex cepstra. I understand this requires unwrapped phase, but know of no FFT equivalent that doesn't wrap the phase. Does anyone know of unwrapped phase FFT code? ...

Dear All, I would like to share your smart idea to calculate the magnitude of a complex, and without calculating the sqrt value of the power of...

Dear All, I would like to share your smart idea to calculate the magnitude of a complex, and without calculating the sqrt value of the power of the complex. (a+bj)*conj(c+dj)/magnitude(c+dj)=? Thanks, Fan

I'm using FFTWf version 3.2 and have a question about whether I can do in-place 2d real-complex and complex-real? The docs seems to say yes but...

I'm using FFTWf version 3.2 and have a question about whether I can do in-place 2d real-complex and complex-real? The docs seems to say yes but I get very bad results. Thanks, RON C

Hi again, I'm sorry to insist on the same subject but I don't see clearly the difference in the relationships between EbN0 and SNR for complex...

Hi again, I'm sorry to insist on the same subject but I don't see clearly the difference in the relationships between EbN0 and SNR for complex and real signals, specially because in the matlab version I have (7.0.1) the "Describing the Noise Level of an AWGN Channel" of the help is different from the last version of Matlab (or the online help). For complex signals: Eb/N0 = S/N * fs/R For re...

Dear All, I am learning how to use viterbi in GSM Channel Equalization. As a newer, I have some basic questions about this method. Q1, What...

Dear All, I am learning how to use viterbi in GSM Channel Equalization. As a newer, I have some basic questions about this method. Q1, What I learn from textbook, viterbi can handle bit sequence with some mistakes, and output correct bit sequence. How can it handle complex data inputs? Because the received signal are complex. Q2, Can you kindly introduce some papers with simple math deriv...

I suspect the answer is "no!", but is there a good approximate way (better than abs(re) + abs(im)) to calculate the magnitude of a complex...

I suspect the answer is "no!", but is there a good approximate way (better than abs(re) + abs(im)) to calculate the magnitude of a complex number that doesn't involve square roots or division? How about one that includes division, but not square roots? I'm looking for something that'll be fast on a PC initially, but will later be moved to a platform with an embedded processor with an F...

Lets say we design a filter which can give quadratic phase response. H = exp( j * alpha * w^2...

Lets say we design a filter which can give quadratic phase response. H = exp( j * alpha * w^2 ). (http://www.dsprelated.com/showmessage/113932.php?Sort=mostrecentfirst) Since it will won't have odd symmtery in phase does it mean that zeros of freq transfer function wont be complex conjugates and therefore will have complex tap coefficients in time domain. (I understand that if a filt...

I'm looking for a method (preferably of low computational complexity) that will allow me to extend a sum of complex exponential from a...

I'm looking for a method (preferably of low computational complexity) that will allow me to extend a sum of complex exponential from a small period to a greater one. More precisely I have (discrete): sum(a_i * E^(i*2pi*f_i + theta_i)) for t over {1,K} for some set of a_i, f_i, theta_i... and would like to produce: sum(a_i * E^(i*2pi*f_i + theta_i)) for t over {1,N} for N > > K K is

I'm using a microcontroller (dsPIC30F3013) to do an FFT on some "real" data (from a microphone) and I don't have enough internal RAM to get...

I'm using a microcontroller (dsPIC30F3013) to do an FFT on some "real" data (from a microphone) and I don't have enough internal RAM to get the frequency resolution I need. I found a forum entry by Rick Lyons as follows: -quote- Does the dsPIC33 allow you to perform 512-point FFT on complex-valued input samples? If so, there's a way to perform a 1024-point *real-input* FFT using ...

Hi. i read a lot of article focusing on real input. In physical world, does the input in complex form? If exist, where it comes from and what...

Hi. i read a lot of article focusing on real input. In physical world, does the input in complex form? If exist, where it comes from and what is the application? Or actually it is just theory only? Thanks

hello forum, Two sinusoids of different frequency w1 and w2 are orthogonal if integral of their product (one time the complex conj of the...

hello forum, Two sinusoids of different frequency w1 and w2 are orthogonal if integral of their product (one time the complex conj of the other) gives zero. That is only true if the integral of integration is T, and and the period of w1 and the period of w2 fit an integer number of times in T... That means that two sinusoids are orthogonal only if their frequencies are different and one an ...

Hello, I would like to know how to generate a gaussian complex vector ( ~N(0,1) ) with Matlab. Thanks you for your help. Vincent

Hello, I would like to know how to generate a gaussian complex vector ( ~N(0,1) ) with Matlab. Thanks you for your help. Vincent

I am searching for a robust wavelet based MATLAB toolbox that could be used for complex images. There are some good toolboxes available however...

I am searching for a robust wavelet based MATLAB toolbox that could be used for complex images. There are some good toolboxes available however they can only work for real images. Thanks Sylvia

Good morning all, This conundrum may be due to it being too early in the day for me to think clearly, so please tell me where I've gone...

Good morning all, This conundrum may be due to it being too early in the day for me to think clearly, so please tell me where I've gone wrong! It would appear to me that complex conjugation would satisfy the properties of linearity and time-invariance, and therefore could be categorised as an LTI operation. However, clearly it creates frequency content that was not present in the origin...

Hi All, I have two problems that have been giving me sleepless night, I will appreciate assistance from members of this group. I have two...

Hi All, I have two problems that have been giving me sleepless night, I will appreciate assistance from members of this group. I have two complex numbers , let say z1= a+ ib z2=c +id if z1 and z2 are not equivalent. By multiplication, z1z2 = (ac-bd) +i(ad + bc). What expression in term of z1 and z2 will give ac + ibd. Secondly, I am trying to do simple multiplication using ta...

Can anyone please tell me one thing that in communication receiver, after performing matched filtering and timing recovery seperately for I...

Can anyone please tell me one thing that in communication receiver, after performing matched filtering and timing recovery seperately for I and Q data, whether equalization works separately on I and Q data or we first get the complex signal (combining I and Q) and perform equalization on complex signal (or what is preferable) ? I am sorry for if this question is silly but its my first que...

The article "Complex Algorithm R&D: Harder Than Many Think" has been published on the Math Blog. The article discusses using...

The article "Complex Algorithm R&D: Harder Than Many Think" has been published on the Math Blog. The article discusses using advanced mathematics to solve real world problems, including specific examples in video compression and speech recognition. The article is for a general audience and may be useful for anyone interested in this specialized field. The article discusses the mathematical...

Hello, I am trying to model the effect of group delay of an analog filter with complex transfer function H(f) on a phase modulated signal s(t),...

Hello, I am trying to model the effect of group delay of an analog filter with complex transfer function H(f) on a phase modulated signal s(t), with a complex spectrum S(f). The analog filter I would like employ is a Chebyshev n=4, with 0.1dB ripple, but the exact filter is not important right now. In continuous time, the answer seems simple: The filtered signal is just the inverse fourier...