Hi all I'm working on GMSK modem simulation in MATLAB. I'm almost done with the modulation part albeit i'm not sure if the model I used...

Hi all I'm working on GMSK modem simulation in MATLAB. I'm almost done with the modulation part albeit i'm not sure if the model I used is correct adding to my trouble is the ambiguity with the Power Spectral Density of the GMSK modulated signal (also the MSK modulated signal). Here I'm writing the algorithm I followed to do the simulation: bitrate=4000bps BT=0.3 1.calculated ...

Hi all I'm working on GMSK modem simulation in MATLAB. I'm almost done with the modulation part albeit i'm not sure if the model I used...

Hi all I'm working on GMSK modem simulation in MATLAB. I'm almost done with the modulation part albeit i'm not sure if the model I used is correct adding to my trouble is the ambiguity with the Power Spectral Density of the GMSK modulated signal (also the MSK modulated signal). Here I'm writing the algorithm I followed to do the simulation: bitrate=4000bps BT=0.3 1.calculated ...

Hi there, I'm trying to simulate the adjacent channel(ACI) performance of a continuous phase modulation(CPM) scheme so that I can determine if...

Hi there, I'm trying to simulate the adjacent channel(ACI) performance of a continuous phase modulation(CPM) scheme so that I can determine if my modulator/demodulator meets a particular ETSI performance specification. I'm not sure if my simulation should include AWGN as well as the ACI? Ultimately I'm trying to chose a combination of CPM modulation parameters (alphabet size, pulse shape, pu...

I have came across a so-called soft symbol mapper in OFDM system, which I understand it is modulation by soft values, but how to do it? for...

I have came across a so-called soft symbol mapper in OFDM system, which I understand it is modulation by soft values, but how to do it? for example, QPSK modulation will make [0 0] [0 1] [1 0] [1 1] to [-0.7071-0.7071i] [-0.7071+0.7071i] [+0.7071-0.7071i] [+0.7071+0.7071i], how about soft symbol mapper?

Hello friends, I am little confused that why do we always apply fourier transform for amplitude modulation, frequency modulation why not laplace...

Hello friends, I am little confused that why do we always apply fourier transform for amplitude modulation, frequency modulation why not laplace transform. Second question is that when I studied control system then everywhere Laplace Transform is used. So please tell me why we use LT in controls and why FT in communication.

Hi, I have a doubt regarding 1 other project. I have to get the modulation transfer function of an image (and the same image defocused)....

Hi, I have a doubt regarding 1 other project. I have to get the modulation transfer function of an image (and the same image defocused). The defocus is either induced by constructing a bessel filter (similar to airy functions, defocus created by unfocused thin lens). Even though I already designed the filter, I am currently using a webcam to get the defocus by altering the focus of the le...

Hi! I want to ask what is the best digital modulation scheme used for high speed telephone modems?. Thanks. Charvee

Hi! I want to ask what is the best digital modulation scheme used for high speed telephone modems?. Thanks. Charvee

Hi, I want to make fsk modulation. For example my baseband signal is "1010001110". Ones are represent by 2200 hz and zeroes are by 1100 hz. Now I...

Hi, I want to make fsk modulation. For example my baseband signal is "1010001110". Ones are represent by 2200 hz and zeroes are by 1100 hz. Now I know that for generating a fsk signal, I have to generate a signal that shows ones(as callded s1) and another one that shows zeros(as called s0). And when "1" comes, it has to be shown in s1; and when "0" comes, it has to be shown in s0; WHILE it is sho...

QUESTION Do you know where I might find tabulated coding gains for different coding schemes? For example BICM, LDPC, MLC, Turbo Codes...

QUESTION Do you know where I might find tabulated coding gains for different coding schemes? For example BICM, LDPC, MLC, Turbo Codes etc. CONTEXT I have been working for a while on different coding schemes, so far I have studied block codes, convolutional codes and trellis coded modulation. I am interested in coding for the bandwidth limited channel, so coded modulation is of more use ...

Hi there, i was just playing around with the modulation function on Matlab here are the simple commmands I run: ? t = 5; ?...

Hi there, i was just playing around with the modulation function on Matlab here are the simple commmands I run: ? t = 5; ? t=0:0.01:10; ? y=power(sin(pi*t/(2*T)), 0.5); ? mod = modulate(y, 250, 44100, 'am'); ? plot(t, mod) so I wanted to know what I should choose my sampling frequency to be - right now it is set to 44100, but how do I know this is appropriate? When I plot (t,mod), i...

Hi, It's recently come to my attention that the FM index of modulation is also the peak phase deviation in radians. This was in regards...

Hi, It's recently come to my attention that the FM index of modulation is also the peak phase deviation in radians. This was in regards to a question about the linear region of phase/frequency detector. My question is (and excuse me if the answer is simple): How can you show that this is indeed the case? A mathematical proof would be interesting. Thanks! ...

Hi folks, Can anyone give me some idea about demapping/detection algorithm for Dual carrier modulation . its used in OFDM based UWB...

Hi folks, Can anyone give me some idea about demapping/detection algorithm for Dual carrier modulation . its used in OFDM based UWB systems. DCM is like mapping same databits into different constellation points from different constellation diagrams. In OFDM UWB 4databits are mapped into 2 I/Q points in (16 QAM like constellation) from 2 different constellation digrams. http://www.wi...

Hi, I made a complete DSSS demodulator with DBPSK and DQPSK demodulation. In the case of DQPSK demodulation I've got the same PN_code on I...

Hi, I made a complete DSSS demodulator with DBPSK and DQPSK demodulation. In the case of DQPSK demodulation I've got the same PN_code on I and Q branchs. What is the advandatage to put different PN_code on I and Q ? And what is the advantage to make a complex spreading like this : At spreading (modulation) : (I+jQ).(PN_I+jPN_Q) So I signal becomes : I.PN_I-Q.PN_Q and Q signal become...

Hi,everyone I'm kind of a newbie in everything relatated to modulation/demodulation and as I am now working with it on Matlab, I'm just...

Hi,everyone I'm kind of a newbie in everything relatated to modulation/demodulation and as I am now working with it on Matlab, I'm just learning it by myself. With the amplitude modulation I get by, but I now have to demodulate a BPSK modukated signal and I don't really know how to do it. What I have is a 847KHz signal (actually it's the side band signal) modulated with what I think is t...

Hi there, I have the following question: 1) For each modulation scheme, there is a corresponding bandwidth efficiency (let's call it n). n =...

Hi there, I have the following question: 1) For each modulation scheme, there is a corresponding bandwidth efficiency (let's call it n). n = R/B where R is the data rate and B is the bandwidth. My question is can I simple say R = n*B no matter how big B is. i.e. can I reach higher data rate by increasing the bandwidth using the same modulation scheme. 2) If the above equation can not be a...

While I was reading through the aacPlus decoder code, I wasn't sure what the following function's usage, is this an implementation of the IMDCT?...

While I was reading through the aacPlus decoder code, I wasn't sure what the following function's usage, is this an implementation of the IMDCT? Or something else? Any help is appreciated. Thanks in advance. /* * * \brief Perform complex-valued inverse modulation of the subband * samples stored in rSubband (real part) and iSubband (imaginary * part) and stores the ...

Hi all, I am told that there are Shannon Limit (Eb/No) with every code-rate BPSK modulation. Are there Shannon Limit (Eb/No) with every...

Hi all, I am told that there are Shannon Limit (Eb/No) with every code-rate BPSK modulation. Are there Shannon Limit (Eb/No) with every code-rate QAM(like 16QAM and 64QAM) modulation? Any suggestions will be appreciated! Best regards, Davy

hi, i want to take FM modulation to a signal which is changing in its amplitude and frequency. Give me a idea how to...

hi, i want to take FM modulation to a signal which is changing in its amplitude and frequency. Give me a idea how to start. Thanks, Senthil This message was sent using the Comp.DSP web interface on www.DSPRelated.com

What is coherent OFDM? Does this refer to the type of modulation I use(coherent modulation - QPSk, BPSK)?

What is coherent OFDM? Does this refer to the type of modulation I use(coherent modulation - QPSk, BPSK)?

Given an analog bandlimited signal, is it possible to create a continuous time reversible procedure to reduce the bandwidth without losses?...

Given an analog bandlimited signal, is it possible to create a continuous time reversible procedure to reduce the bandwidth without losses? In the other words, is it possible to create a bandwidth reducing analog modulation? Looks like the answer is no, however I can't make a mathematical proof of this. VLV