Dear all, Hi, I have a question regarding macrodiversity in Wimax. I have read that MBS can achieve macrodiversity by using the same...

Dear all, Hi, I have a question regarding macrodiversity in Wimax. I have read that MBS can achieve macrodiversity by using the same symbol, modulation, subchannel etc in C80216e-04_275r1 & C80216e-04_359r3. My questions are: 1. I was confused about whether this macrodiversity is actually achieved by receiving the same burst from multiple base station (a.k.a single frequency network) o...

Hello to the DSP community! Has anybody ever tried to plot the S-curve (for timing recovery purposes) for the GFSK? This modulation has a...

Hello to the DSP community! Has anybody ever tried to plot the S-curve (for timing recovery purposes) for the GFSK? This modulation has a pretty complicated expression given the Gaussian shape filter being used. So, using the timing error formula derived by Cowley and Sabel for the Muller & Mueller (M&M) method I obtained a very small valued S-curve (order of 10^(-5)). Does anybody know about a...

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 All I did a simple simulation for adaptive DFE to replicate the results of proakis. It gives me proper results. But this simulation is just...

Hi All I did a simple simulation for adaptive DFE to replicate the results of proakis. It gives me proper results. But this simulation is just a normal one, no pulse shaping, no carrier modulation, only one sample per symbol. To add the channel effects, I am convolving my tx signal with channel. But when I tried to do the same simulation at passband with 12 samples per symbol, I am not getti...

Hi all, I have a signal of the following form - S(t) = A*cos(B*cos(2*PI*FM*t) + C*cos(2*PI*SF*t)) FM is the modulation frequency, and SF...

Hi all, I have a signal of the following form - S(t) = A*cos(B*cos(2*PI*FM*t) + C*cos(2*PI*SF*t)) FM is the modulation frequency, and SF the signal frequency. I have written an algorithm to extract C*cos(2*PI*SF) from S(t) above. The algorithm is implemented on the C6711, and I use a 16 bit ADC to digitalize S(t). I'd like to carry out an analysis as to how accurate my algorithm is....

Hey all, We intend to purchase the PSK modulator IP core. The core outputs the complex data vectors (I,Q of 10/14 bit width). To realize the...

Hey all, We intend to purchase the PSK modulator IP core. The core outputs the complex data vectors (I,Q of 10/14 bit width). To realize the standard PSK output, what operation should we perform with these output data (like addition)?

Hi all, I have been surprised while researching this topic, at the lack of clear information concerning the implementation of...

Hi all, I have been surprised while researching this topic, at the lack of clear information concerning the implementation of optimal detection/matched filtering in the general case - that is, when the baseband signal is not a staircase-like function. Let me explain... We are transmitting 4 level symbols over a wireless channel, (FM modulation is used in the air, but the DSP sees demodul...

Hi all, Ive come to another promblem with the project I'm doing on DSL. I can't seem to figure out if a 180 degree phase reversal (hardware...

Hi all, Ive come to another promblem with the project I'm doing on DSL. I can't seem to figure out if a 180 degree phase reversal (hardware inversion) will make the demodulation of the DMT signal impossible. As I see it there will be a problem with phaseshifts that holds the carrier waveform "positive" for more than a half period, like the QAM modulation on the picture. http://www...

Hi, I aim to design a burst to achieve maximum spectral efficiency for a vsat network. I wish to evaluate a feedforward NDA(blind) symbol...

Hi, I aim to design a burst to achieve maximum spectral efficiency for a vsat network. I wish to evaluate a feedforward NDA(blind) symbol recovery for 16QAM/16APSK or higher level of modulation. which is the most widely acceptable algorithm for the same. please let me know the reference as well where I can get the entire understanding. I am not using MATLAB I plan to write my own c code for the...

Hello Forum, I found in a book the Fourier transform interpreted as a filtering operation: Given a signal f(t), The complex coefficient at...

Hello Forum, I found in a book the Fourier transform interpreted as a filtering operation: Given a signal f(t), The complex coefficient at frequency w0 given by the Fourier transform is X(w0). Say that the signal spectrum is X(w+w0) as if it was the result of a modulation. X(w+w0) is centered at w0. The Fourier integral has {f(t)*exp(-j*w0*t)} as integrand. This step can be seen as a de...

I have a question regarding I/Q modulation occuring in a multi-rate system. Here's the background: fs = 20e6; fc = 20e6; (my carrier...

I have a question regarding I/Q modulation occuring in a multi-rate system. Here's the background: fs = 20e6; fc = 20e6; (my carrier freq) I = cos( 5mhz ) Q = 0; I first upconvert both I and Q to fs = 120e6 in two stages, interp by 4, and interp by 3/2. Then I form the passband signal: passband = I*cos( fc ) - Q*sin( fc ). Now I retrieve the I and Q components by I_rcv = passband...

hi: We all know that DSM is good because it's abaility to push Q noise to higher frequency band. My question is does DSM only work for Q...

hi: We all know that DSM is good because it's abaility to push Q noise to higher frequency band. My question is does DSM only work for Q noise? What about if the data already corrupted by noise? therefore would DSM work if the noise is the combination of background and quantization noise.? I have done some matlab coding(first order) on it and it works a bit but i dont know if it's ...

hi: We all know that DSM is good because it's abaility to push Q noise to higher frequency band. My question is does DSM only work for Q...

hi: We all know that DSM is good because it's abaility to push Q noise to higher frequency band. My question is does DSM only work for Q noise? What about if the data already corrupted by noise? therefore would DSM work if the noise is the combination of background and quantization noise.? I have done some matlab coding(first order) on it and it works a bit but i dont know if it's ...

Hi, I'm trying to gain an understanding of how to do timing recovery or symbol synchronization in a digital radio receiver but I need something...

Hi, I'm trying to gain an understanding of how to do timing recovery or symbol synchronization in a digital radio receiver but I need something clarified. The methods I have found information on (Mueller & Mueller, Early-late, Gardner etc) seem to be intended for linear modulation schemes but what about nonlinear ones, such as FSK? The only thing I've found so far seems to be for CPM by means o...

Hi I have to communicate with telephone which is sending us data that is in voice band and FSK modulated. I dont have an fsk modem so i am...

Hi I have to communicate with telephone which is sending us data that is in voice band and FSK modulated. I dont have an fsk modem so i am trying to do FSK demodulation in software. I'll record that data in a wave file and then analyise it. i dont have any signal processing background and i am stuck in this problem. please help according to the standard: Mark is represented by 1300Hz, ...

Hi I have to communicate with telephone which is sending us data that is in voice band and FSK modulated. I dont have an fsk modem so i am...

Hi I have to communicate with telephone which is sending us data that is in voice band and FSK modulated. I dont have an fsk modem so i am trying to do FSK demodulation in software. I'll record that data in a wave file and then analyise it. i dont have any signal processing background and i am stuck in this problem. please help according to the standard: Mark is represented by 1300Hz, ...

A continuous data signal is quantized and transmitted using a PCM system. If each data sample at the receiving end of the system must be known...

A continuous data signal is quantized and transmitted using a PCM system. If each data sample at the receiving end of the system must be known to within 0.5 percent of the peak-to-peak full-scale value, how many binary symbols must each transmitted digital word contain? I assumed that pk-pk of the signal is some constant A. So what is represented by Ax0.5%??

Hello Every One! Actually I am working on Single Side Band (SSB) Modulation/Demodulation. I have successfull programmed the Modulator...

Hello Every One! Actually I am working on Single Side Band (SSB) Modulation/Demodulation. I have successfull programmed the Modulator and the Demodulator. But Now I have one problem, that I want extract the Carrier Frequency from the SSB (transmitted) signal at the receiver end. Any one can guide my in the respect. Thanks.......................... ____________________________________...

Hello All I have been scratching my head over this problem for the last one week. My ultimate aim is to replicate the result I have got...

Hello All I have been scratching my head over this problem for the last one week. My ultimate aim is to replicate the result I have got using normal simulation for baseband one sample per symbol, to passband. Now, my system parameters are: Fc=12KHz, Fs=48KHz, BW=4KHz, Uncoded, QPSK modulation, square pulse(with unit energy) for pulse shaping. So Ns=samples per symbol=12. Assuming, a...

Hi - I'm working with some basic over air coms at around 1KHz frequency. For the time, let's say there's no modulation, just simple tone...

Hi - I'm working with some basic over air coms at around 1KHz frequency. For the time, let's say there's no modulation, just simple tone codes. (beat the drums!) Let's (also) say received signal is exposed to broadband noise bursts that are spread across from (pick 2 numbers) 600Hz to 1300Hz. These burst can be higher than the signal being received. My ADC is sampling at 15Khz. Ahead of t...