Hello, Which of the following two definitions is correct for convolution of 2 complex signals? (1): x1(t) convolve x2(t) = int from -inf...

Hello, Which of the following two definitions is correct for convolution of 2 complex signals? (1): x1(t) convolve x2(t) = int from -inf to +inf [ x1(tau) x2*(t-tau) ] dtau (2): x1(t) convolve x2(t) = int from -inf to +inf [ x1(tau) x2(t-tau) ] dtau Here x2*(.) is the complex conjugate of x2(.). I would appreciate it if you could also point me to a textbook which confirms your...

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. ...

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

For FM demodulation, on the face of it, it appears that demodulating it using a real baseband and is no different from using a complex baseband....

For FM demodulation, on the face of it, it appears that demodulating it using a real baseband and is no different from using a complex baseband. The end result is the demodulated baseband. However it would appear that there is probaly an advantage (since most implementations using a DSP describe this method) demodulating using a complex baseband as opposed to a real baseband signal. So w...

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

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 ...

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...

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...

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

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 ...

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 -- "

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