Adaptive Filter | ADPCM | ADSP | ADSP-2181 | Aliasing | AMR | Anti-Aliasing | ARMA | Autocorrelation | AutoCovariance | Beamforming | Bessel | Blackfin | Butterworth | C6713 | CCS | Chebyshev | CIC Filter | Circular Convolution | Code Composer Studio | Comb Filter | Compression | Convolution | Cross Correlation | DCT | Decimation | Deconvolution | Demodulation | DM642 | DSP Boards | DSP/BIOS | DTMF | Echo Cancellation | Equalization | Equalizer | ETSI | EZLITE (Ez-kit Lite) | FFT | FFTW | FIR Filter | Fixed Point | FSK | G.711 | G.723 | G.729 | Gaussian Noise | Goertzel | GPIO | Hilbert Transform | IFFT | IIR Filter | Interpolation | Invariance | JTAG | Kalman | Laplace Transform | Levinson | LPC | McBSP | MIPS | Modulation | MPEG | Multirate | Notch Filter | Nyquist | OFDM | Oversampling | Pink Noise | Pitch | PLL | Polyphase | QAM | QDMA | Quantization | Quantizer | Radar | Random Noise | Reed Solomon | Remez | Resampling | RTDX | Sampling | Sharc | TI C6711 | Undersampling | Viterbi | Wavelets | White Noise | Wiener Filter | Windowing | XDS510PP | Z Transform

Name that modulation...

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 th...

What does PCM mean to you?

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 wan...

Re: Theoretical and practical consequences of groupdelay variation in DMT.

Hi Morten, Considering DVBT modulation (which is also an OFDM signal), the effect of groupdelay variation over the carriers used by the modulation will result in varying rotations for each of the points in the QAM constellation. => without equalizer , the MER (modulation - error rati...

Re: How to recognize patterns

So you have a signal that has some form of modulation on it? Or do you have multiple signals that you need to deinterleave? There are lots of available algorithms for detecting modulation types etc, check out your local IEEE Xplorer, heck even google should produce some. I am not sure what y...

Data Rate, bandwidth

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...

FM modulation

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 ...

Re: How does PCM-Demodulation work?

Randy Yates wrote: (snip) > I'm guessing so. In almost 30 years, I've never heard of a > PCM-demodulator, but I am getting old and senile. Where did you come > across this term? Well, the M is for modulation, but I agree using the term "demodulator" in that case is unusual. In the pa...

Re: the measure of "wavyness" of signals

This sounds like modulation to me. Have you looked into calculation of the modulation index? If the "wavyness" is modulation, then the proper way to measure the "wavyness" is to pass the signal through a detector appropriate to the type of modulation and measure the statistics of the output ...

Digital modulation!!

Hello all, Can anybody tell the key motivation of the inventor (who is the genius behind it?) to use digital modulation instead of its analog counterpart and how did it happen historically and experimentally? Regards, Santosh ...

What is the best modulation scheme?

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 coul...

Is QFM ever used? Can it decrease the bandwidth needs of FM video signals?

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 Googl...

adaptive modulation

Hi, I am looking for matlab source code to simulate adaptive modulation. can anyone help me? regards, Azadeh ...

16, 64 non-uniform modulation

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 ...

Modulation transfer function

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 des...

Removing modulation of a PAM signal and reconstruction the information

Hi! Using Matlab, I need to send a message through a simulated AWGN channel. I have defined the signal pulse to be a square pulse with different amplitudes depending on the bit, a0 for a 0 and a1 for a 1. I modulate the signal by tx = tx .* cos(2*pi*fmod) where tx is kron(bits,signalpulse). ...

Re: viterbi traceback - continuous data mode

> Don't forget to compare TCM and BICM. Hi Eric, That's Bit-Interleaved Coded Modulation, right? You mentioned in another thread (august 2004) that "Bit Interleaved Coded Modulation further decouples the system from the modulation and signal processing, and is known to always be as good or b...

Re: FM demodulation phase unwrapping

cincydsp@gmail.com wrote: ... > You shouldn't need to "unwrap" your phase value, as it shouldn't ever > break out of the [-pi, pi] interval. ... Doesn't that depend on the amount of modulation? I know of nothing inherent in FM (PM, actually) that limits the modulation to any part...

IQ modulator &upconvertor(AD9857)

I am working on AD9857 which copmrises an IQ modulator and in fact is a quadrature up convertor Using 14 bits I Q input data , I want to try out various modulation schemes like AM, FSK,FM,BPSK,GMSK, QPSK and QAM. I`ve tried IQ modulation in different (analogue) shchemes with MATLAB using IQ in for...

Re: What is the analog equivalent of aliasing?

"Green Xenon [Radium]" wrote in message news:4828ded3$0$5698$4c368faf@roadrunner.com... > Hi: > > Aliasing is a digital entity. What is the analog equivalent of aliasing? > Aliasing isn't a digital entity it's a sampling entity. That you digitize the samples has nothing to do wi...

Re: Fourier of 50 Hz 100% AM of 20 KHz (PWM) ?

The spectrum of a PWM signal is complicated, because PWM is kind of like a frequency or phase modulation. The spectrum depends on exactly how the width of the pulse is determined from the modulation waveform. A width exactly proportional to the amplitude of the samples of the modulation conta...

Re: What's Es/No mean?

Hi john, Thank you for your help! A simple question: Does 10*log10(rate) mean the code gain of BPSK modulation? And is there code gain of QAM modulation? Any suggestions will be appreciated! Best regards, Davy ...

Multicarrier modulation scheme vs FSK

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 ...

diff encoding in GSM

Hi does anyone know why differential encoding of data is done in GSM before modulation ? ( As I understand , this is not to enable noncoherent detection, but is related to the connection between gmsk and msk which is an offset-PAM modulation. ) shankar ...

frequency modulation

What type of hardware is typically used for frequency modulation? ...

Re: Digital bandwidth

billoo wrote: > I am currently working on a project which involves determining the > relationship between the the "bandwidth"(as my advisor puts it) and > power consumption of an I/Q transmitter. This might not be related to your question, but I have always found the term "bandwidth"...

Digital Modulation Scheme

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

Calculating BER for optical communications

Hi! I would like to calculate the BER of an optical communications system. The only known value is the total collected intensity as a function of time (I thus can calculate mean intensity, variance,...). The modulation format doesn't matter. The simplest is the best; so we can take OOK mod...

Linear vs Nonlinear modulation as their carrier recovery algorithm?

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 modula...

BER performance for BPSK and QPSK

Hi, I read this statement from a book "The bit error probability for QPSK modulation is the same as for BPSK, and hence, the results for BPSK can be used also for the QPSK case". The author of the book simulated the BER performance for BPSK modulation in multipath and AWGN channel. May I know ...

Removing flutter

Anybody know of any techniques for removing wow & flutter from recordings? I'm currently converting to digital form some cassette recordings of myself playing guitar. I'm using a pretty good cassette deck which I've cleaned very thoroughly, but I'm still getting a bit of flutter on playback,...

linear modulation and cpm

Hi, The bandwidth in quadrature modulation is typically assumed to be max(B1,B2) where B1 = bandwidth of I(t) B2 = bw of Q(t) rf signal = I(t) cos wt + Q(t) sin wt = A(t) cos(wt + phi(t) ) w = carrier frequency It seems to me that for a given amount of phase change...

Recovery of IQ modulation frequency (DVB-T)

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 gi...

Question about coding for high order modulation

Hi, I have a question about channel coding. As I know, coding is used for improving system performance. At the same time, coding will result in lower spectral efficiency, except TCM. For higher modulation, the coding gain is useful only when its performance is better than that of lower order ...

FM INDEX OF MODULATION QUESTION

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 sh...

Modulation question

Hi we have an RF transmission that has some data modulated into it. The RF is transmitted at just under 1GHz. My question is how can we find out what the modulation scheme is? we are not sure even if it is analogue or digital, i.e. whether it is AM/FM or FSL/PSK/QAM etc., though suspect pr...

Modulation Problem

If linear modulation systems are to be compared on an equal peak power basis (all have equal peak signal values), show that: A. SSB has a (S/N)out that is 3 dB better than DSB. B. SSB has a (S/N)out that is 9 dB better than AM. Help with this problem would be greatly appreciated. Thank you in ...

why fourier transform in AM and FM why not LT

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 ...

OFDM-coherent

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

Re: Sinusoidal Chirp signal

"Lilian" wrote in message news:YeSdnTDHCvzDCS_eRVn-uw@giganews.com... > Hi, > > For Linear FM, I have used > i(n)=Aexp(-jpi(cot(angle))*(n2/256))=Aexp(-j*theta). > But I am not sure for sinsoidal chirp signal.I think it cant be used > as i(n)= A cos(theta). Because instant...

Max Bit rate question

If I have a digital FM system do you have any background on the max bit rate you can achieve for a given depth of modulation? eg for 250kHz depth of modulation I can achieve only 500kb/s. Does this sound right? This must be pretty basic stuff I am sure and related to Shannons law somewhere. T...