Hi list, I understand the meaning of spatial diversity and frequency diversity. I'm in search of a proper definition for "Modulation...

Hi list, I understand the meaning of spatial diversity and frequency diversity. I'm in search of a proper definition for "Modulation Diversity". I know that such a thing exists (Google told me), but I'm not able to find the definition or at least understand from some of the papers which mention this term. Any directions? Best Regards, Nagaraj

Hi: What waveform[s] of FSK do[es] the EDT [European Deaf Telephone] protocol use? FSK = Frequency Shift Keying Quote from...

Hi: What waveform[s] of FSK do[es] the EDT [European Deaf Telephone] protocol use? FSK = Frequency Shift Keying Quote from http://www.deaflibrary.org/v18/v18.html : "EDT Operational Mode -- The modulation is frequency shift keyed modulation (i.e. carrier is 10 ms before a character is transmitted and removed 1s after the last character) using Recommendation V.21(1) frequencies. Th...

Hi, QPSK has - 4 constellation points; 16 QAM -16 constellation points; 64 - 64 constellation points. 16QAM vs QPSK -> Now with the 16...

Hi, QPSK has - 4 constellation points; 16 QAM -16 constellation points; 64 - 64 constellation points. 16QAM vs QPSK -> Now with the 16 possible points in the constellation diagram we have 16 possible symbols. For this 16 symbols we need 4 bits for coding . Compared to the QPSK modulation now we have doubled the transfer rate when using the same symbol clock.But compared to the QPSK, points

Hi all, I am working on the coexistence study between BT and WLAN. Anyone knows where are the spec on modulation and pulse shaping for BT and...

Hi all, I am working on the coexistence study between BT and WLAN. Anyone knows where are the spec on modulation and pulse shaping for BT and 802.11 a, b, g WLAN? cfy30

Hello Forum, Consider a baseband signal of a certain bandwidth B. Using analog modulation (either AM, FM or phase modulation), in a...

Hello Forum, Consider a baseband signal of a certain bandwidth B. Using analog modulation (either AM, FM or phase modulation), in a single channel environment(i.e. not worrying about possible interference between multiple users and channels) can we impress that bandwidth B on carrier of any frequency f? Does the carrier frequency need to be always much larger than the bandwidth of the signal i...

Hi, with respect to your community, I'm just starting my journey with signal processing topic. I'm currently working on small voice activity...

Hi, with respect to your community, I'm just starting my journey with signal processing topic. I'm currently working on small voice activity detection (VAD) C++ code snippet. After reading .wav file, passing it trough FFT and feeding with obtained data MFCC algorithm I got my MFCC coefficients. Now I'm little confused. How should I calculate modulation energy in 4Hz frequency (and in bandwith...

Hi, I got a question regarding to modulation entropy of audio signal. There is some literature I found about this...

Hi, I got a question regarding to modulation entropy of audio signal. There is some literature I found about this topic, http://www.irit.fr/recherches/SAMOVA/FeaturesExtraction.html#me. I've already read sample .wav file. But now, how do I calculate entropy of this sampled signal with the lenght of N samples? How should I understand, in this case (in paper equation from above), propability of...

Hi, I am observing something that is very counter-intuitive to me: I/Q modulation is very susceptible to phase noise? In an experiment I...

Hi, I am observing something that is very counter-intuitive to me: I/Q modulation is very susceptible to phase noise? In an experiment I plot "phase noise" vs. "SNR" and see a constant slope of ~20dB/dec. I use a real baseband signal, multiply it by cos(2*pi*fc*t) and then multiply it again by cos(2*pi*fc*t + phi(t)) where phi represents the phase noise. Finally, a simple image filter. I...

Hi I have written Matlab script for BPSK modulation. The way my code works is as follow: series of 0 and 1----> NRZ data (continuous...

Hi I have written Matlab script for BPSK modulation. The way my code works is as follow: series of 0 and 1----> NRZ data (continuous rectangular pulses with amplitude -1 and 1)---> multiply by carrier----> add noise--> multiply by carrier---> integration---> detection---> Bit Error collection? I would like to know can anyone tell me where I should apply DAC and ADC ? I am wondering shoul

Hello All, The classical modulation scheme is defined as, x(n)*cos(w_0*n) 0.5*[X(w+w_0) + X(w-w_0)] - eq(1) Similarly, text books...

Hello All, The classical modulation scheme is defined as, x(n)*cos(w_0*n) 0.5*[X(w+w_0) + X(w-w_0)] - eq(1) Similarly, text books also define frequency shifting as, x(n)*exp(j*w_0*n) X(w-w_0) - eq(2) It appears to me that scheme in eq(2) is much cleaner way of modulating a signal than scheme in eq(1). Second scheme requires complex multiplication in time while first sche

Hi All, I'm looking at FSK modulation in practical multi-path channels. What type of equalizers are suitable for FSK ? What type of equalizers...

Hi All, I'm looking at FSK modulation in practical multi-path channels. What type of equalizers are suitable for FSK ? What type of equalizers are appropriate for other non-coherent modulation schemes ? Highly appreciate if you could provide any relevant paper or a book. Thanks in advance. Dan _____________________________ Posted through www.DSPRelated.com

Hi all. I am starting out on signal processing. Conceptionally I think I understand the advantages of pulse shaping and raised cosine. But I am...

Hi all. I am starting out on signal processing. Conceptionally I think I understand the advantages of pulse shaping and raised cosine. But I am not clear where this is used in practice. Is pulse shaping just used on purely digital transmission i.e. A pulse train. Or is it combined with digital to analog modulation. E.g. QPSK. Any help would be much appreciated. Thanks in advance Steve. ...

Hi! I want to make sure that what I've learned so far about Trellis-Coded Modulation is correct which is why I'm asking for...

Hi! I want to make sure that what I've learned so far about Trellis-Coded Modulation is correct which is why I'm asking for confirmation. d_free^2 is minimal the sum of squared Euclidean distances between two symbol sequences that can be generated by the TCM, right? The coding gain is 10*log10(d_free^2/d_min^2) where d_min is the minimum Euclidean distance for a pair of "uncoded" symbo...

Sirs, Let me first say that probably this is a very basic question. In case of modulating carrier signals with data and doing de-modulation...

Sirs, Let me first say that probably this is a very basic question. In case of modulating carrier signals with data and doing de-modulation at the receiver, what would be the disadvantage if data is simply added to the carrier frequency and then performing filtering at the receiver to remove the carrier signal and recover the data. Thanks, manish

Hello, I'm studying and maintaining an existing tele-communication system. I guess it's a BPSK modulation but not quite sure. The...

Hello, I'm studying and maintaining an existing tele-communication system. I guess it's a BPSK modulation but not quite sure. The transmitted data is a Chirp(up sweeping frequency)header followed by modulated data body. On the receiver side, the incoming data is auto-correlated with a locally stored up-chirp waveform and then defive 2 parameters, one is the sign the other is a delay inf...

Hello, I recently found myself interested in digital modulation techniques. For a hobby project I plan to implement modulation and...

Hello, I recently found myself interested in digital modulation techniques. For a hobby project I plan to implement modulation and demodulation so I can later test it using soundcards for transmitting little text messages via sound between neighbouring laptops. The main goal is to learn something and have fun -- not to build something useful. I'm sure some of you could provide valuable sug...

Hello, As I understand it, phase/frequency modulation is usually achieved by generating by directly modifying the argument of a...

Hello, As I understand it, phase/frequency modulation is usually achieved by generating by directly modifying the argument of a sinusoid. However, if the task was to frequency modulate an existing signal which itself we don't generate, is there a standard way doing so, e.g. by superposing a modulating signal (probably a piecewise continuous signal) on the existing signal? In my case, pha...

Hi, I have implemented overlap-add method for granular pitchshifting and eventually I realized, that since the "overlapping" is...

Hi, I have implemented overlap-add method for granular pitchshifting and eventually I realized, that since the "overlapping" is basically multiplying with a hann window or something, it basically is a ring-modulation. I unfortunately verified this on a spectrum analyzer - it added f+m and f-m to the testing frequency. But this means the only way to avoid the ringing is to make the window larger...

Hi all, can anyone share with me the equation for the BER-SNR for PPM modulation? I am trying to study the BER performance for AWGN channel in...

Hi all, can anyone share with me the equation for the BER-SNR for PPM modulation? I am trying to study the BER performance for AWGN channel in matlab. Thanks.

I have a pretty elementary question. For an unshaped, 2-FSK signal, the modulation index h is defined as the ratio of the difference between...

I have a pretty elementary question. For an unshaped, 2-FSK signal, the modulation index h is defined as the ratio of the difference between the two tone frequencies to the symbol rate. For shaped 2-FSK, how is h usually defined? I can think of a few possibilities: (1) Base it on the peak frequency excursion exhibited by one isolated symbol, ignoring ISI from other nearby symbols. ...