Hi all, I've got an analyic signal for which I'm designing an IIR filter with purely real valued coefficients. I'd like to look at the...

Hi all, I've got an analyic signal for which I'm designing an IIR filter with purely real valued coefficients. I'd like to look at the impulse response of this filter, but since the normal impulse is purely real and the coefficients are all real, the impulse response is also purely real. In order to get a complex impulse response, I need a complex impulse. Is this: .... 0 0 0...

Hello, I measured the execution time of a 2^20 point FFT in MATLAB. It takes 703ms do do one 2^20 point complex FFT in MATLAB. If I do a 2^20...

Hello, I measured the execution time of a 2^20 point FFT in MATLAB. It takes 703ms do do one 2^20 point complex FFT in MATLAB. If I do a 2^20 complex FFT in C it takes 3.3 seconds. How come it takes 4 times longer in C compared to in MATLAB? Has anyone compared the Intel Math Kernel Library (MKL) FFT with MATLAB in terms of execution time? Thanks for any replies.

Hi all, I have a need to sample audio from my sound card and process it. However, the hardware I am processing it on works faster in...

Hi all, I have a need to sample audio from my sound card and process it. However, the hardware I am processing it on works faster in complex domain than real domain. I know this may sound funny, but it is true. Read on... In essence, I need to convert a real stream sampled at N to a complex stream sampled at N/2. Not sure what the best way to do this is or if it can even be don...

I am working on a fixed-point DSP-based coherent BPSK modem. In order to improve the computational dynamic range of the clock recovery...

I am working on a fixed-point DSP-based coherent BPSK modem. In order to improve the computational dynamic range of the clock recovery and carrier tracking algorithms, I put a complex limiter on the complex baseband. It comes after the signal has been filtered with a rectangular pulse with length equal to one bit time. What it does is compute phi=atan2(y/x) and then looks up sin(phi) and cos(...

seldata=rand(1,25)> 0.5; seldata2=2*seldata-1; %serial data in the form of -1 and 1 complex=complex(seldata2) %Mapping...

seldata=rand(1,25)> 0.5; seldata2=2*seldata-1; %serial data in the form of -1 and 1 complex=complex(seldata2) %Mapping of data in complex nos aparadata=reshape(seldata2,5,5) %S to P in a 5x5 matrix sym=fliplr(aparadata) %Flipping of 5x5 matrix to acheive symmetry data=[sym aparadata] %data matrix wh

I have an overconstrained system of equations (m equations in n variables with m> n) where the variables are complex. Using the...

I have an overconstrained system of equations (m equations in n variables with m> n) where the variables are complex. Using the Moore-Penrose pseudoinverse method of solution is giving me results that are terribly counterintuitive. Does anyone know what exactly is minimized in the least squares sense when the variables and solution coeficients are complex? Thanks, Bob -- "

Hi All, My question is as follows. When calculating an N-point IFFT with the inputs conjugate symmetric (real output), this can be performed...

Hi All, My question is as follows. When calculating an N-point IFFT with the inputs conjugate symmetric (real output), this can be performed using a single N/2-point IFFT and some pre and post processing. Is there any method to do this (use a single N/2-point IFFT) with half the inputs set to zero instead of the complex conjugate? (and thus getting the complex analytic output instead of the ...

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, estdev

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

I am using FFTW 3.0.1 with a C-program I'm developing. My input data consists of a block of complex data for M channels ordered in the following...

I am using FFTW 3.0.1 with a C-program I'm developing. My input data consists of a block of complex data for M channels ordered in the following fashion: input = [ chan1_sample0, chan1_sample1,...,chan1_sampleN-1, chan2_sample0,...,chan2_sampleN-1,...,...,chanM_sample0,...,chanM_sampleN-1] I would like to take advantage of the "Advanced Complex DFT" capability (e.g.-fftw_plan_many_dft()) to...

Hi, I have a question regarding complex numbers in FFT. I used an ADC to convert an analogue signal to a digital signal and send it to the...

Hi, I have a question regarding complex numbers in FFT. I used an ADC to convert an analogue signal to a digital signal and send it to the computer through the parallel port. It is a 8-bit ADC. When i got the data inside the computer, how do I change it into a complex number? Can anyone advise me on how to deal with this problem? Another thing is about the N-points. How do i determin...

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? ...

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, 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.

[Question] A problem originated in engineering: H is a (N*SF+L-1)*(N*SF) complex matrix and is generated with a Matlab...

[Question] A problem originated in engineering: H is a (N*SF+L-1)*(N*SF) complex matrix and is generated with a Matlab command H=filter(h,1,[eye(N*SF);zeros(L-1,N*SF)]) where h is a L*1 complex vector. C is a (N*SF)*(N*K) complex matrix and is generated with a Matlab command C=kron(eye(N),c) where c is a SF*K matrix whose columns are Walsh codes. I find out with a Matlab program that C'*H'*H...

Hi, May I know what is the main difference between real and complex spreading code for CDMA? When should we apply real spreading code &...

Hi, May I know what is the main difference between real and complex spreading code for CDMA? When should we apply real spreading code & when should we apply complex spreading code? Many thanks.

Hello everybody, I'm implementing a filter as Ecualization to simulate a digital system communication in JAVA. My trouble is easy to...

Hello everybody, I'm implementing a filter as Ecualization to simulate a digital system communication in JAVA. My trouble is easy to understand, I have a matrix with complex values, and I need to compute the pseudoinverse matrix. I found package/class/methods like the package JAMA/JAMALAB that makes the pseudoinverse Matrix with real values, but... with complex?? Know anybody some package...

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

Why am i getting complex output when i compute the inverse fft of a vector of complex numbers? This does not happen always and the imaginary...

Why am i getting complex output when i compute the inverse fft of a vector of complex numbers? This does not happen always and the imaginary part of the output is very small compared to the real part. thanks for any insight jeremy

Hello out there, I am confused about hardware implementation of complex sampling. Can I just set up two ADCs sampling at the same rate, but...

Hello out there, I am confused about hardware implementation of complex sampling. Can I just set up two ADCs sampling at the same rate, but with their clock signals 90 degrees out of phase, or do I actually need to multiply my input signal by a sine-wave? I assume that by sampling with 2 ADCs with out-of-phase clocks, this is the equivalent of multiplying by complex sine wave which is in p...