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, 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...

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

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)?

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...

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

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 ...

As was kindly suggested to me, I've been experimenting with OFDM for my TCP/IP over tin cans project. Since the modulation on the "wire" is...

As was kindly suggested to me, I've been experimenting with OFDM for my TCP/IP over tin cans project. Since the modulation on the "wire" is at baseband, and I'm using a sound card as a DAC, this means my signals are audible. When modulating a random bitstream, the resulting audio is full of popping noises. I have taken steps to ensure that no clipping is occurring, so these pops are really...

hey guys, just wanted to know if any1 could please shred sum light on wat would the differnce in demodulation schemes of double side band...

hey guys, just wanted to know if any1 could please shred sum light on wat would the differnce in demodulation schemes of double side band suppressed carrier and single side band suppressed carrier. This is what i done with matlab coding for modulation and demodulation. 1. DSB-SC: - Modulation: (message signal 500hz) multiply by (carrier frequency 7000hz) ie: cos (2 pi 500 t) x cos (2pi700...

Hi all can any one tell me how to do 16, 64 non-uniform modulation in matlab,and how to calculate the distance between points, BER Thanks

Hi all can any one tell me how to do 16, 64 non-uniform modulation in matlab,and how to calculate the distance between points, BER Thanks

Hi, How the pilot symbol assisted QAM works ? What are the symbol information sent on this Pilot ? It's in the same frequency band than...

Hi, How the pilot symbol assisted QAM works ? What are the symbol information sent on this Pilot ? It's in the same frequency band than the QAM modulation ? I think we send a BPSK pilot over the QAM modulation in time duplex ? Do you have good paper on that, I found nothing over google... Thanks

Hey, What is the difference between multicarrier modulation and FSK (Frequency Shift Keying)? Can OFDM considered to be a hybrid of the...

Hey, What is the difference between multicarrier modulation and FSK (Frequency Shift Keying)? Can OFDM considered to be a hybrid of the two? Thanks TD

Humans resolve 2 nearly equal musical tones by listening for the "beat" notes (given that trigonometry formulas indicate that adding 2 sinusoids...

Humans resolve 2 nearly equal musical tones by listening for the "beat" notes (given that trigonometry formulas indicate that adding 2 sinusoids is equivalent to modulating one sinusoid). So why can't one resolve two very close sinusoids by examining the envelope of the mixed waveform for some sort of modulation artifact? If the envelope fits some fraction of one full cycle of modulation, t...

I have a very basic question with regards to beam-forming or MRC. When I apply complex weigths for example while doing co-phasing for MRC,...

I have a very basic question with regards to beam-forming or MRC. When I apply complex weigths for example while doing co-phasing for MRC, does this phase rotate my constellation. Everywhere I read , I never see a beamforming effect on the demodulation. Given Im using a PSK kind of modulation,don't these complex weights affect my constellations.After all isnt pSk modulation some form of Sin(wct + ...

Hello, I am a bit unsure how the demodulator recovers the original IQ modulation frequency of a DVB-T baseband signal. In the standard the...

Hello, I am a bit unsure how the demodulator recovers the original IQ modulation frequency of a DVB-T baseband signal. In the standard the frequency "fc" is (IMHO) not specified, however there could be read (ETSI EN 300 744 V1.5.1 (2004-06), Page 45) "A subsequent up-conversion process then gives the real signal s(t) centred on the frequency fc". So it should be correct to look for the "ce...