Sirs, For some of the cellular communications standards, multiple modulations schemes are adopted (16QAM, 64QAM etc.). I have feq questions on...

Sirs, For some of the cellular communications standards, multiple modulations schemes are adopted (16QAM, 64QAM etc.). I have feq questions on this, - are these modulation used for modulation of carrier signals or this is baseband related modulation -- assuming this is for carrier modulation, how does the receiver know what modulation has been done used while transmission -- if 16Q...

We have two digital modulations, both are the same, the only different is the symbol rate. Usually low symbol rate modulation have less BER...

We have two digital modulations, both are the same, the only different is the symbol rate. Usually low symbol rate modulation have less BER than high symbol rate modulation. But my question is if in the case of a bad carrier stability, high symbol rate modulation could have less BER than low symbol rate modulation. I think answer is YES, but i am not sure.

I am little unsure about line coding in the digital baseband transmission. I know that in passband modulation, for most cases we do apply...

I am little unsure about line coding in the digital baseband transmission. I know that in passband modulation, for most cases we do apply some pulse-shaping signal to make sure that we are limiting the bandwidth of the symbols before modulation, so that we avoid ISI, and even from spilling to another the adjacent channel in Multi-channel modulation systems. But, I was reading some informatio...

Hi, I have a few basic doubts in the QPSK modulation & drawing of constellation, 1) For the QPSK modulation complex signal is required (or)...

Hi, I have a few basic doubts in the QPSK modulation & drawing of constellation, 1) For the QPSK modulation complex signal is required (or) real signal is enough? 2) In the drawing of constellation x-axis is the real value ,y-axis is imaginary & how the angle is represented in the constellation? 3) If the QPSK signal is the complex signal,which formula will suits for the representation...

Hi, I simulate (or want to simulate) an RF system. My simulation Nyquist rate is 50GHz, the signals are 8 Msamples long and there is a...

Hi, I simulate (or want to simulate) an RF system. My simulation Nyquist rate is 50GHz, the signals are 8 Msamples long and there is a 5MHz transmission at 1GHz (using standard I/Q modulation). In any case, I am playing around with modulation. When I create a modulation sequence fc = 1GHz + 6.103515624999999kHz % note the non-integer multiple m1(t) = cos(2*pi*fc*t) then...

Hi, Turbo codes implementation through BCJR algorithm for binary modulation is straightforward. Can someone inform me about how to do that...

Hi, Turbo codes implementation through BCJR algorithm for binary modulation is straightforward. Can someone inform me about how to do that for multi-level modulation, say QPSK or 16-QAM. Specifically, how does the decoder function. Any reference paper is also welcome. Thanks. _____________________________ Posted through www.DSPRelated.com

Which modulation scheme is most suitable for transmitting information (a bitstream) over an acoustic channel? i.e. a loudspeaker outputs...

Which modulation scheme is most suitable for transmitting information (a bitstream) over an acoustic channel? i.e. a loudspeaker outputs the modulated signal and a cell phone microphone picks up the acoustic signal and extracts the information from the modulated signal. I'm looking for a modulation/signaling scheme which is robust with respect to ambient noise in the acoustic channel.

Shouldn't amplitude modulation really be called "Magnitude Modulation"? After all, in FM, the amplitude is still being modulated, but the...

Shouldn't amplitude modulation really be called "Magnitude Modulation"? After all, in FM, the amplitude is still being modulated, but the magnitude is constant. Or maybe I have too much time on my hands. S.

Hi all!! I have implemented BPSK modulation with DSK 6713.I'm writting a program to implement BPSK modulation and demodulation on the same Kit...

Hi all!! I have implemented BPSK modulation with DSK 6713.I'm writting a program to implement BPSK modulation and demodulation on the same Kit DSK 6713, but it doesn't run. Can we implement BPSK modulation and demodulatio on the same Kit DSP?. I wil post my source code later! By the way! I also have a project about QPSK demodulation, but when I recover carrier wave, I only recover sin wave(in_pha...

hi a short time ago, I posted I was doing computed modulation. I now have 2 nice sidelobes. The q is this: Where mathematically, and more...

hi a short time ago, I posted I was doing computed modulation. I now have 2 nice sidelobes. The q is this: Where mathematically, and more to the point, where should I account for the necessity in code of doing an DC offset to audio array samples in order to achieve the "Carrier" in AM modulation ? procedure: I simply add some close sine frequencies to get a 300-3000 hz waveform ( ...

I am doing a project to implement ZERO WATERMARKING (Instead of embedding an external watermark, the zero-watermarking technique extracts...

I am doing a project to implement ZERO WATERMARKING (Instead of embedding an external watermark, the zero-watermarking technique extracts some essential characteristics from the host image and uses them for watermark embedding and extraction). Now for this purpose i am using CHAOTIC MODULATION. In short the steps involved for CHAOTIC MODULATION will be, 1. The original image has been coded i...

Start with logic 0s and 1s. Convert them to pulses that look roughly like Gaussian bell curves each going from near-zero to maximum to...

Start with logic 0s and 1s. Convert them to pulses that look roughly like Gaussian bell curves each going from near-zero to maximum to near-zero in one bit time, 0s going negative, 1s going positive. Use said negative-and-positive-going pulses to frequency-modulate a carrier. What is the name of this type of modulation? If my description of the mechanics of this modulation scheme i...

PCM stands for pulse code modulation. Can there be PCM without modulation? Is it still PCM if the modulation carries more than one bit per...

PCM stands for pulse code modulation. Can there be PCM without modulation? Is it still PCM if the modulation carries more than one bit per symbol? Radium is confused (or a clever troll), but his ravings raise an interesting question. Jerry -- Engineering is the art of making what you want from things you can get. ??????????????????????????????????????????????????????????????????????? ...

Hello all, What kind of modulation scheme that will suit high speed transmission (at least to 1 Gbps)? And obvious choice will be those...

Hello all, What kind of modulation scheme that will suit high speed transmission (at least to 1 Gbps)? And obvious choice will be those highly spectral efficient modulation scheme like OFDM. However, if the linearity requirement and the sensitivity to phase noise are very high, then OFDM could be out of question especially for system that operate at very high frequency such as 40-70GHz . ...

Hello, I am writing a filter ( for pulse shaping ) followed by a modulation ( BPSK ) scheme for a satellite transmission. I...

Hello, I am writing a filter ( for pulse shaping ) followed by a modulation ( BPSK ) scheme for a satellite transmission. I have a result, but I would like to hear your opnion about it. I am using a root raised cosine filter for the input stream, and applying quadrature modulation after it. For instance, suppose I want to transmit this symbol stream ...

Hi: Is Quadrature Frequency Modulation used? What for? AFAIK, Quadrature Amplitude Modulation uses a combo of AM and...

Hi: Is Quadrature Frequency Modulation used? What for? AFAIK, Quadrature Amplitude Modulation uses a combo of AM and Phase-Shift-Keying. So QFM would use a combination of FM and PSK. Would this decrease the bandwidth required for broadcasting FM luminance video signals? I did a Google Search for ?Quadrature Frequency Modulation? on http://www.google.com/search?hl=en&lr=&q=%22Quad...

Hi, I thought the code gain of one channel code is independent upon modulation, but the simulation in MATLAB/Simulink with...

Hi, I thought the code gain of one channel code is independent upon modulation, but the simulation in MATLAB/Simulink with different modulation shown different codegain. Channelcode: Convolutional, coderate 1/2, memory depth 6, traceback 32, 3bits-softdecision Bitrate after decoder: 20kbit/s 1. FM, with 10khz deviation, 40khz passband before FM-Demodulate, 25khz baseband after FM-Dem...

Does anyone know of a good page that describes that Pulse Position Modulation PPM is? I am a newbie to modulation. Thanks

Does anyone know of a good page that describes that Pulse Position Modulation PPM is? I am a newbie to modulation. Thanks

Can I get some feedback on my thought process below for choosing a modulation technique? I am in the process of choosing the modulation and...

Can I get some feedback on my thought process below for choosing a modulation technique? I am in the process of choosing the modulation and coding for the following system: - frequency band: 2 - 20 Hz - bit rate: configurable 2 - 16 bps - transmitter: battery powered - receiver: PC based (i.e. lots of processing power) - channel: some burst noise - adjacent signals/channels: none - traff...

Dear all, Just found this great forum on DSP. This is my first post and hope someone can help. I am searching for the knowledge on GMSK...

Dear all, Just found this great forum on DSP. This is my first post and hope someone can help. I am searching for the knowledge on GMSK demodulation and found that some articles say that some carrier/timing recovery algorithms (like Gardner, Early-Late etc) are only applicable to LINEAR modulation scheme. my questions are: 1) what does linear and nonlinear modulation mean? what is the di...