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AM demodulation

Hi there! I'm finding hard to get information about "switched gain AM demodulation" and how to implement it. Apparently this demodulation techique involves synchronization with the signal carrier.. Can anybody provide some hints? Regards, Luke ...

AM demodulation

Having looked through countless websites and books, I've learnt loads, but not what i'm looking for: An algorithm for AM demodulation... Can anyone help? ...

FM demodulation

Hello, I want to write a subroutine to implement FM demodulation. The input should be in the format of IQ. How can I do this and where can I read about the technique and the implementation technique and mathematics behind it? Any help is much appreciated. Regards ...

req help

hello i am a final yr project student, and i have to develop c language codes for am and fm demodulation ... i will have to create a dll file which can bbe accessed by labview for display. i could not find any specific directives towards software implementation of am/fm demodulation...can s...

Digital PLL and FM demodulation

Hello, PLL is a good way to do FM demodulation in analogue domain. What about its use in digital domain? Why not to use a digital PLL to do FM demodulation? what is advantages(if any) and disadvantages of this technique? Regards ...

FM demodulation

i came to know that FM demodulation can be done through envelope detection. i have implemented the FM demodulation using envelope detection and i was unable to detect the original signal. i have not implemented the limiter circuit for this. i have passed the FM signal directly to the BPF followed...

FM rejection for AM demodulation

What is the exact meaning of "FM rejection for AM demodulation"? How can I test this parameter if I had an AM receiver? Thanks! ...

Repetition Coding and Soft demodulation

Dear All, Okay, probably this sound a bit silly, but what happens when repetition coding is used and when soft demodulation is used ? Soft QAM demodulation produces Log Likelihood Ratio (LLR), and should I take average value of the repeated symbols ? Here's the simple view of the receiver ...

sin and cos signal generation for IQ demodulation in dsp

Hello, I am doing IQ demodulation in DSP. Only one reference signal(sin) fo is coming as reference. I have generate 2fo,4fo from it and also generate orthogonal signal of each of it for IQ demodulation. All these frequency should be phase looked with the reference signal.My question is how to g...

Sample rate and baud rate issue

I'm working on FSK demodulator with the TMS320C6711 DSK. I've done this demodulation with the method where the signal and its delayed version are multiplied together and then low-pass filtered. But this demodulation technic is only working if the sample rate is an integer multiple of the baud rate. ...

software demoduation

Hi all, I am new to much of this, so thanks in advance for your patience. Where can you find C++ (or C or C#) source code for ASK, FSK, PSK, QAM, PPM, and BPSK demodulation schemes? I have a feeling that if they exist they won't be free, but that's a problem for another day...Matlab and LabView ...

Fax signals demodulation

Dear friends, I'm trying to develope a PC application to receive and send faxes using ula samples of telephone channel. Can any one help me to find some usefule guides, trial applications, sources, ... on demodulation of V.21, V.27ter and V.29 signals? Thanks in Advance This message...

xr2211 & non coherent fsk demodulation

Hello, I am using the XR 2211 to demodulate a non coherent fsk signal. It works but I would like to know how to evaluate the theoritical BER performance of this demodulation. But all the non coherent fsk receivers that are mentionned on the web dont use a pll ... any idea ? thank you very m...

DPSK's relation with OFDM and Demodulation

Hi, I understand that simplified equalization is one of the good reasons for going with OFDM. But, how do they manage it ? That is, The OFDM may be viewed as using many slowly-modulated narrowband signals rather than one rapidly-modulated wideband signal. So, The Differential modulation such a...

BPSK demodulation

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 hav...

Gbps BPSK demodulation

Hi all, I'm looking for an architecture dedicated to a Gbps BPSK demodulation. I will have I and Q available on a 4 bits ADC @ 3Gbps.. Do you know what is the best archtiecture in regards to this high data rate ? I though about CORDIC perhaps, but I'm not sure it can handle this data rat...

Cramer rao bound on estimating amplitude of the signal using complex demodulation

Hello, I am finding the amplitude of the signal using complex demodulation (quadrature demodulation). I wanted to know maximum accuracy to which the amplitude of the one of the frequency contained in phase modulated signal(which is the input) can be estimated.The accuracy to which the amplitu...

how much dopler effect are DVB-T receivers on the market conquer?

how many people are here designing the DVB-T demodulation ASIC? I am very interested in the performance of DVB-T receivers on the market or to be on the market,and i would like to discuss the OFDM demodulation technology here with you. 3x! ...

how much doppler effect are DVB-T receivers on the market able to conquer?

how many people are here designing the DVB-T demodulation ASIC? I am very interested in the performance of DVB-T receivers on the market or to be on the market,and i would like to discuss the OFDM demodulation technology here with you. ...

demodulation problem

Hello. I am working on a software demodulator and have a few questions. First off let me say that I am just getting into this DSP stuff. Anyways... I have a file of samples representing a bpsk modulated wave. The popular method of demodulating seems to be through I/Q channels so that the ...

System Sensitivity based on Power Spectral Density

Hi all, I hope you can help me with this problem because I'm really confused by it at this stage. I have implemented a demodulation scheme on a dsp processor and I'm currently trying to establish the sensitivity in terms of radians per root Hz. The signal before demodulation is - cos(...

SNR DSSS WCDMA

hi everybody, Did you know if the SNR (to compute the BER vs SNr) is compute after or before the complex demodulation DQPSK (Dot and Cross) ? After the demodulation, we integrate the signal (Dot and Cross) and then we make the symbol decision ? Thanks ...

thx for clay and julius, 'Still mathetical problem, but for AM demodulation with FIR filter"

Clay, thanks for your opinion... my problem is the mathematical equation for how the FIR filter to process demodulation for AM. oya, bout the windowing method, u tell me...i found the equation for bandpass filter ideal. i read a book, and i got the equation for unideal filter. is it h=w.hd? h...

FSK coherent demodulation in Rayleigh Fading Channel

We know coherent and noncoherent FSK demodulation can be done by using correlator and energy detector. In Fading channel case with noncoherent demodulation, we can use the energy detector. But in coherent case, how could we use the channel state information to detect signal..... BFSK: h is ...

Convert demodulation I/Q to soft Data

I found the signal after demodulation module are Data_I[q:0] and Data_Q[q:0]. How to convert Data_I[q:0] and Data_Q[q:0] to soft information Data[q:0]? May you please recommend some references? Any suggestions will be appreciated! Best regards, Robert ...

RTTY (AFSK) demodulation

Hi, has somebody here implemented a RTTY (AFSK) decoder. Any suggestions how to proceed ? I've found some technical abstracts about FSK demodulation in the WEB like: - frequency discriminator with IIR resonator - frequency discriminator with FIR bandpass filter - digital PLL Any idea how com...

OFDM demodulation question

Here's my question: In doing the OFDM (like DVB-T) demodulation, why do people just talk about carrier frequency sync and carrier phase noise but not carrier phase itself? Does that mean OFDM is not coherently demodulated? Thank you for your help! -- Harry ...

Single Side Band (SSB) Demodulation

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...

MSK demodulation using PLL

Can I implement a MSK demodulator using PLL? Basically I want to demodulate MSK using FM demodulator IC. The IC uses a PLL for FM demodulation. What are the drawbacks in using PLL ( if I can use one ) as compared to coherent demodulator with carrier recovery? Thanks ~ Kaushal ...

Need Help on Costas Loop for coherent GMSK demodulation

Dear all, I saw in google that costas loop can be used as the carrier recovery mechanism for coherent GMSK signal demodulation, but I did not find any detailed article about it. Can anybody give a good reference to implement costas loop for gmsk? Any useful weblink or technical article will b...

Blind demodulation of things like V.34

Hi all, I have never implemented blind demodulation of QAM, and seen all the problems first hand. However, the material I have seen on the subject is all based on despinning the constellation by looking for the corners of a square (or squarish) array sticking out. In schemes like V.34 where...

modulation/demodulation - orthogonal fonctions

Hi all, Im working on an (synthetic) acoustic experiment: I have a receiver that records waves emitted by two sources S1 and S2. So the receiver records R=S1+S2. I would like to "filter" R to get only S1 or S2. Is there any way of doing that ?? S1 and S2 are defined in the same frequ...

msk demodulation

Hi evrybdy, I am new to this grp.I am working on a project involving demodulation of msk signals.The transmitter has been implemented using a AD9851 DDS chip.The transmitter switches between 16MHz and 24MHz depending on the incoming bits.At the receiver,I am using AD6620 to downconvert...

Re: Approach to demodulating AM-signals?

Hello Tam, > > If you want the best AM demodulation then you need to recover the carrier > via squaring then lock into twice the carrier freq using a PLL. Then divide > this freq by 2 and multiply and filter times the original AM. Synchronous AM > demodulation - you don't need a proces...

Timing Recovery for Blind Demodulation

Hi! I'm working on a simulation of blind QAM demodulation in Matlab. So far i have implemented AGC, Carrier Phase tracking loop and a CMA equalizer - but i have not yet implemented symbol timing recovery. I have seen numerous references to Band-Edge Timiing Recovery (BETR), wich seem to do the...

a question about the effect of channel estimation and equalization in ofdm

in OFDM systems, the LS channel estimation result should be H'=P'/P if we compensate the received data symbols with one tap scheme, the equalization result should be D''=D'/H' = P*D'/P'; one the right of the above equation, D'/P' looks like the differential decoding result so the cohe...

complex GMSK demodualtor with knowledge about preamble

Hello, everybody! I have a question about baseband GMSK signal demodulation. For my signal parameters are following: 1) BT=0.3, 2) Symbol rate equals sample rate 3) I know preamble sequence I suppose to apply match filter on preamble sequence for timing and frequency offset recovery. Is this...

DIgital V's Analog Demodulation

Hi all, I'm implementing demodulation schemes in digital form and I'm currently trying to establish what the advantages and disadvantages are of each domain. I've written down what I think are the most important, and would be interested in hearing if I've covered all the bases and if the info...

FM Demodulation - Complex baseband versus Real baseband

For FM demodulation, on the face of it, it appears that demodulating it using a real baseband and is no different from using a complex baseband. The end result is the demodulated baseband. However it would appear that there is probaly an advantage (since most implementations using a DSP descri...

Newbie: System Performance

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 b...