Hi All, I am trying to figure out the *real* motivation behind using MLSE (Maximum Likelihood Sequence Detection) as opposed to a...

Hi All, I am trying to figure out the *real* motivation behind using MLSE (Maximum Likelihood Sequence Detection) as opposed to a symbol-by-symbol detection that maximizes the log-likelihood function. As a tangible example, the standard optimum receiver for CPM (Continuous-Phase Modulation) signals is defined to be a correlator followed by an MLSE detector (Ref. Digital Communications by J...

Hi to all, I'm a student, I'm currently studying: AM, PM, FM, PCM modulation, noise impact on signal etc. I'd like to be able to graphical...

Hi to all, I'm a student, I'm currently studying: AM, PM, FM, PCM modulation, noise impact on signal etc. I'd like to be able to graphical view spectrum of baseband and bandpass signal implicated . I'd like to know, if there is any software, that could help me to be better understand the matter, where I can manually input the function which represent the signal eg. S(t) = Ac [ 1 + cos ( 2 ...

Hi All, 1) I want to implement MODEM with 128Kbps at 100Khz with high doppler shift channel. Which modulation technique would be suitable...

Hi All, 1) I want to implement MODEM with 128Kbps at 100Khz with high doppler shift channel. Which modulation technique would be suitable . Whether I can go with OFDM or SC-FDMA? Any suggestions 2) Is it possible to simulate 128Kbps with Matlab Thanks & Regards, Ammankumar.S

Hi: What is the maximum amount of bits-per-symbol that can be broadcasted on a telephone line is MFSK [Multiple Frequency Shift Keying] is...

Hi: What is the maximum amount of bits-per-symbol that can be broadcasted on a telephone line is MFSK [Multiple Frequency Shift Keying] is the modulation scheme -- without causing the error rate to get too high? According to wikipedia, if MPSK [Multiple Phase Shift Keying] is used, the maximum bits-per-symbol is 8 Quotes from http://en.wikipedia.org/wiki/Phase-shift_keying#Higher-order...

Hi all, I m trying to find the modulation schemes and pulse shaping filters most popular in HF communication systems. 1. I figures out that...

Hi all, I m trying to find the modulation schemes and pulse shaping filters most popular in HF communication systems. 1. I figures out that OQPSK, QPSK and FSK are most popular methods and are used in more than 70% of HF comm, while other non-popular methods are M-QAM and M-PSK. Please correct me. 2. I couldnt find any info on pulse shaping though, can an expert direct me to a good referenc...

To all the guardians of signal processing, iam writing a matlab code for the pulse amplitude modulation and demodulation. i have done in the...

To all the guardians of signal processing, iam writing a matlab code for the pulse amplitude modulation and demodulation. i have done in the following way 1.a sine signal with 1000Hz frequency. 2.then a square wave(carrier) of 10000Hz frequency. 3.multiplied these 2 for sampling. 4.quantized the resultant signal. 5.i have added some noise by using rand() fn. 6.at the receiver side i corr...

Dear DSP-Friends, I want to convert .WAV-Files offline into delta sigma modulated single-bit-streams, therefore I wrote a small C application...

Dear DSP-Friends, I want to convert .WAV-Files offline into delta sigma modulated single-bit-streams, therefore I wrote a small C application to do the WAV-file-handling, the upsampling and the delta sigma modulation. This works quite well for delta sigma modulators up to the second order, but for a better SNR-ratio especially at low OS-rates (8x to 16x) I am searching for stable modulators of ...

Hi There, I have a TMS320C6416T DSP starter kit and wish to examine various modulation schemes. Which daughterboards offer DAC...

Hi There, I have a TMS320C6416T DSP starter kit and wish to examine various modulation schemes. Which daughterboards offer DAC (digital-to-analog) and ADC (analog-to digital) capabilities? Your time and suggestions will be greatly appreciated Jaco

Hello all, I am involved in the development of an underwater modem. Right now I am dealing with the simulation stage with simulink. The...

Hello all, I am involved in the development of an underwater modem. Right now I am dealing with the simulation stage with simulink. The modulation scheme I am using is a non-coherent FSK. The carrier frequencies are 20kHz and 22kHz. At the demodulator part, I have designed a matched filters scheme, with both bandpass FIR filters at 20 and 22kHz respectively. The question is, which should ...

Hello All, Can anybody tell me what would be the diffference in the constellation for pi/2-shift QPSK (not pi/4 QPSK). and normal QPSK. This...

Hello All, Can anybody tell me what would be the diffference in the constellation for pi/2-shift QPSK (not pi/4 QPSK). and normal QPSK. This is one of the modulation types proposed as part of the TG3c proposal(IEEE 802.15). There is also mention about pi/2 BPSK, pi/2 QAM etc. With regards to pi/2 BPSK, I understand that the constellation would have four points but I was not sure on pi/...

Hello, I am honing my skills on the Physical layer of communication systems. I request the knowledgeable members of this group to help me with...

Hello, I am honing my skills on the Physical layer of communication systems. I request the knowledgeable members of this group to help me with the following topics. I'd appreciate that, and I believe this may help other people who would want similar knowledge. 1) On what criterion do we select the original data bits (like it is 244 bits for UMTS 12.2 Kbps) 2) What would be the optimal le...

Dear all It seems I have forgot all my fundamentals. Can you please guide me on how to add noise to the system. So far I did simulations at...

Dear all It seems I have forgot all my fundamentals. Can you please guide me on how to add noise to the system. So far I did simulations at baseband where we just map the data to symbols and add noise. i.e. for 1/2 rate convolution and 4-QAM modulation, SNR=Eb/NO=1/(sigma^2); and from this find the sigma and multiply with random sequence. But how does this differ at passband? Where my ...

HI All, I am working on timing recover for digital communication receiver. Now, I have got the data to be transmitted. But can you please...

HI All, I am working on timing recover for digital communication receiver. Now, I have got the data to be transmitted. But can you please tell me how can I introduce time delay, so as to check if my receiver is working or not. My system parameters are: Bandwidth: B=4000Hz Sampling Freq: Fs=48000Hz Carrier Freq: Fc=12000Hz Modulation: QPSK Thanks. Chintan

Hi: In the hypothetical situation I describe, dial-up modem telecommunications technology devices use extreme MPSK [Multiple Phase Shift...

Hi: In the hypothetical situation I describe, dial-up modem telecommunications technology devices use extreme MPSK [Multiple Phase Shift Keying] as the modulation scheme. This too-good-to-be-true MPSK uses only 1-symbol-per-second but with a Graham's-number amount of bits-per-symbol. http://en.wikipedia.org/wiki/Graham's_number Now that is a lot of bits-per-baud! If it were pos...

Dear all, I have a question about how to implement Alamouti in a 3x2 MIMO systems and would appreaciate your help on clarifying my...

Dear all, I have a question about how to implement Alamouti in a 3x2 MIMO systems and would appreaciate your help on clarifying my doubt. Consider a 3x2 MIMO system, 3 antennas in TX and 2 in RX, where 2 spatial streams are transmitted and Alamouti is applied in one of the spatial streams. So at time 0 we transmit for each antenna : [a(0) a(1) b(0)], where a(i) means modulation symbol...

Hi: The most advanced dial-up modem [V.92] uses QAM [a mixture of amplitude and phase modulation]. Does this modem use more phases or more...

Hi: The most advanced dial-up modem [V.92] uses QAM [a mixture of amplitude and phase modulation]. Does this modem use more phases or more amplitudes to convey data? For the same amount of bits-per-baud, if you're using less amplitudes, you'll need more phases. Thanks, Radium

I've had some long-standing confusion in this subject and decided to write a paper to attempt to clarify things for myself. I'd be interested to...

I've had some long-standing confusion in this subject and decided to write a paper to attempt to clarify things for myself. I'd be interested to see if others think I'm completely off-track or think my points are valid. http://galois.digitalsignallabs.com/channellengthmodulation.pdf PS: I know there's a lot of sharp, eclectic engineers on comp.dsp, hence my cross-post there. -- % R...

on what basis the fft length is calculated related to the sampling frequency?I want to search for a maximum peak by obtaining the...

on what basis the fft length is calculated related to the sampling frequency?I want to search for a maximum peak by obtaining the spectrum of the signal.I am working on demodulator in that my task is to acquire the carrier from the receive modulated signal.Modulation used is BPSK.It can be used for 300,600,1200,2400,10800,5400 bit rates.sampling frequency is 518400 for 10800 and 5400 bit rate...

on what basis the fft length is calculated related to the sampling frequency?I want to search for a maximum peak by obtaining the spectrum of the...

on what basis the fft length is calculated related to the sampling frequency?I want to search for a maximum peak by obtaining the spectrum of the signal.I am working on demodulator in that my task is to acquire the carrier from the receive modulated signal.Modulation used is BPSK.It can be used for 300,600,1200,2400,10800,5400 bit rates.sampling frequency is 518400 for 10800 and 5400 bit rates,for...

hi all, I"m working on a simulation of comparing OFDM with different modulation schemes (QPSK,QAM) etc'... My question is about the conversion...

hi all, I"m working on a simulation of comparing OFDM with different modulation schemes (QPSK,QAM) etc'... My question is about the conversion from Es/No to Eb/No I'm not sure if I need to take the cyclic prefix under consideration for instance: Es/No=Eb/No+10log10(log2M * Nc) + 10log10(CodeRate) + ... .. 10log10(Tinf/(Tinf+Tcp)) is the last part correct? where Tinf - is the inf...