Hi, I noticed that the value for AWGN & multipath channel could be real & complex value. Thus, in a practical wireless system, these values...

Hi, I noticed that the value for AWGN & multipath channel could be real & complex value. Thus, in a practical wireless system, these values should be real or complex? For simulation purpose, when should I apply the real value and when should I apply the complex value? Or it is dependent on the transmitted signal? Many thanks. Richard

Hi all, I recently got to know there is a type of Fourier Transform called "Generalized or Complex Fourier Transform". It extends the...

Hi all, I recently got to know there is a type of Fourier Transform called "Generalized or Complex Fourier Transform". It extends the frequency domain variable to a strip on the complex plane. There is regularity associated with the transform in this domain. I am not familiar with the complex/generalized Fourier Transform though I knew the Fourier transform with the transform domain variab...

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...

Hello: I'm trying to figure out how best to convert a complex signal to a real. I've heard of one approach that says to take the magnitude...

Hello: I'm trying to figure out how best to convert a complex signal to a real. I've heard of one approach that says to take the magnitude of the complex sample and use that as the real sample. And another approach where you just drop the imaginary part. Are there other techniques? If I'm looking to convert the complex signal to an audio format, is one approach better than the other?...

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.

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

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...

Hi All, I've a rather simple question related to the corelation between two complex baseband signals. I haven't been able to figure it out yet,...

Hi All, I've a rather simple question related to the corelation between two complex baseband signals. I haven't been able to figure it out yet, or find an answer in any of the textbooks that I own. I've finally decided to resort to the wisdom behind 'Ask-the-Audience' life line :) So here is the question: If we compute cross-corelation between two complex-baseband signals, we know that the r...

A DDC requires an output bandwidth of 80% of the output sample rate. A complex mixer generates I and Q signals from the real input, I and...

A DDC requires an output bandwidth of 80% of the output sample rate. A complex mixer generates I and Q signals from the real input, I and Q are decimated and filtered. To achieve the 80% complex bandwidth requirement are the individual I and Q the filter passbands at Fs-out * 0.8 or 0.4? Thanks!

Hi Richard, One of your comments gave me a little laugh-- "I don't have too much problem with complex notation and its advantages per...

Hi Richard, One of your comments gave me a little laugh-- "I don't have too much problem with complex notation and its advantages per se." In contrast, I have a terrible problem with complex notation. I'd even go so far at to call it the "scourge of DSP." Let me stand on my soap box a bit. There is no question that complex numbers are elegant and enable some techniques that could not ...

hi! i make an envelope detector for AM demodulation using Hilbert Transform and complex envelope... but i don't really understand about the...

hi! i make an envelope detector for AM demodulation using Hilbert Transform and complex envelope... but i don't really understand about the advantages of using Hilbert Transform and complex envelope... what is the advantages of using Hilbert Transform and complex envelope? why using Hilbert Transform method is more effective than square-law? and i think i can make an envelope detector...

Is it possible to generate a scalar sampled data stream from a sampled complex data stream without losing information? For example, can I...

Is it possible to generate a scalar sampled data stream from a sampled complex data stream without losing information? For example, can I take complex data that was sampled at 100 Hz. with a bandwidth of +/- 50 Hz around 0 Hz. and convert it to a scalar data stream that is sampled (effectively) at 200 Hz and preserve all the information between 0 and 100 Hz?

Hello Comp.DSP, I need to perform forward and inverse FFT of multi-dimensional, real data. I am already successful to do this using the complex...

Hello Comp.DSP, I need to perform forward and inverse FFT of multi-dimensional, real data. I am already successful to do this using the complex FFT separably. Now I would like to do this using the real FFT for computational savings. However, after I perform real FFT of the first dimension, the data is complex and it seems I must use the complex FFT for subsequent dimensions. It makes s...

Hi all, Suppose my signal is a complex valued signal, and it is complex conjugated with respect to the center t=0. That's to say...

Hi all, Suppose my signal is a complex valued signal, and it is complex conjugated with respect to the center t=0. That's to say f(-t)=f(t)*, where "*" denotes the complex conjugate. Suppose now I do the truncation of above signal into between [-B, B), and I sample it using stepsize dB, then in Matlab, the sampling points are cfs=[-B:dB:B-dB], which has 2B/dB data points, e.g. ...

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 ...

Computing the magnitude of a complex number using a CORDIC is efficient when implemented on FPGAs. I need to compute the inverse of the...

Computing the magnitude of a complex number using a CORDIC is efficient when implemented on FPGAs. I need to compute the inverse of the magnitude of a complex number i.e. (1/|x|) where x is complex using FPGA. Can I use a CORDIC ? If not what is the best pipelined algorithm? Thanks Tom

Howdy, For FM/AM demod, you require a complex baseband. I am downconverting the IF from 1MHz to baseband by multiplying the input stream (12...

Howdy, For FM/AM demod, you require a complex baseband. I am downconverting the IF from 1MHz to baseband by multiplying the input stream (12 bits) from the ADC with Sin and Cosine outputs of a DDS and therefore, generating I, Q I am using standard 18x18 signed multipliers in Xilinx to do the mixing. Is this right or should I use a complex multiplier? The reason why I am asking this question...

I use the following code to get an RFT of an 8 byte complex data array. sPadding=1 in this case. typedef struct...

I use the following code to get an RFT of an 8 byte complex data array. sPadding=1 in this case. typedef struct Complex_Struct { float fReal; float fImaginary; } Complex; ERROR_NUMBER CMyLib::FFTWMake1DInverseFourierTransform(Complex *cpInputVector, float **fppOutputVector, DWORD dwVectorLength, short sPadding) { fftw_complex *in, *out; fftw_plan p; size_t stNumElem...

Hi, I would like to know on the implementation complexity issues beween FIR Filter vs. IIR Filter (Chebyshev). I know that IIR is more...

Hi, I would like to know on the implementation complexity issues beween FIR Filter vs. IIR Filter (Chebyshev). I know that IIR is more complex than FIR. But, in case of the FIR filter has higher order number than IIR, FIR can be more complex. If I have IIR Chebyshev 10th order vs. FIR with 59 Taps. Which one is the most complex one? Thanks, Berry

I have a simple question regarding equivalent complex and real sequences. I know that by sampling in quadrature (I and Q complex samples) you...

I have a simple question regarding equivalent complex and real sequences. I know that by sampling in quadrature (I and Q complex samples) you can satisfy the Nyquist criteria at the sample rate (fs) and if I took real samples only and sampled at 2fs, then I should get equivalent power spectra in the bandwidth 0