Adaptive equalization and synchronization

Started by Tim Wescott in comp.dsp2 years ago 31 replies

How does one maintain synchronization when one is using adaptive equalization? I'm currently working on a highly dispersive, varying channel,...

How does one maintain synchronization when one is using adaptive equalization? I'm currently working on a highly dispersive, varying channel, that needs adaptive equalization to work well. But I've come to realize that one thing that adaptive equalization adapts for is the exact timing of the signal. This means that you can't really used the output of the equalizer as a phase refere...


adaptive precoding and pre-equalization

Started by mobi in comp.dsp10 years ago 1 reply

I was trying to search through literature in order to find advantages and disadvantages of adaptive pre-coding and pre-equalization...

I was trying to search through literature in order to find advantages and disadvantages of adaptive pre-coding and pre-equalization over adaptive post-equalization. I failed. Can anyone point to a good reference. 2ndly on adaptive pre-equalization there are only three papers when we search ieeexplore. I was thinking of using indirect learning architechture as a pre-equalizer mentioned in D....


Equalization in OFDM

Started by Ubaid Abdullah in comp.dsp9 years ago 1 reply

Hi, I am implementing an equalization algorithm for OFDM system. For this, after calculating the channel taps, we need to divide the...

Hi, I am implementing an equalization algorithm for OFDM system. For this, after calculating the channel taps, we need to divide the complex sub-carrier symbols with complex tap values. I was wondering this division takes too many cycles for the DSP implementations. So is there any way of doing equalization in a better way or we have to live with this expensive division operation.


Multipath ISI removal

Started by mite_learner in comp.dsp4 years ago 18 replies

I am studying on equalization for Frequency Shift Keying. I want to know if following paper can be used for equalization of FSK...

I am studying on equalization for Frequency Shift Keying. I want to know if following paper can be used for equalization of FSK system "Self-Recovering Equalization and Carrier Tracking in Two-Dimensional Data Communication Systems " http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1094608&tag=1 Data rate 500kbps, four FSK system. --ML _____________________________ Pos...


Equalization for non-coherent FSK burst modem

Started by mite_learner in comp.dsp4 years ago 12 replies

I want to work on the equalization techniques that are best suited for burst 2-4FSK modems using non-coherent detection. Data rate targeted...

I want to work on the equalization techniques that are best suited for burst 2-4FSK modems using non-coherent detection. Data rate targeted is 0.5Mbps to 1 Mbps. I found many stuff on equalization for QPSK etc but couldn't find any thing on burst FSK modems. Can somebody please suggest me some literature that target this. Also, if some body can point out any existing implementation that works we...


Why not fractional space spampling when frequency domain equalization?

Started by buaawh in comp.dsp10 years ago

as we all konw, fractional space(FS) spampling is robust to nonideal timing synchronization when we do time domain decision-feedback equalization....

as we all konw, fractional space(FS) spampling is robust to nonideal timing synchronization when we do time domain decision-feedback equalization. My question is: why no paper mentioned using FS frequency domain DFE equalization? at least till now I havenot read a paper confirm it. Any comment or reference will be helpful to me. Thanks!


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

Started by MrJiang in comp.dsp8 years ago 4 replies

in OFDM systems, the LS channel estimation result should be H'=P'/P if we compensate the received data symbols with one tap scheme,...

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 coherent demodulation with LS estimation and onetap equalization sees like the differential demodulation...


Frequency /time domain equalization

Started by sair...@gmail.com in comp.dsp10 years ago 2 replies

Hello, I am doing simulation studies for frequency and time domain equalization. From the complexit point of view I completely agreed...

Hello, I am doing simulation studies for frequency and time domain equalization. From the complexit point of view I completely agreed to the fact that frequency domain is better in the number of multiplications/additions. Regarding the performance (BER ) point of view I can see there is a large 3-4 dB gap between time and domain equalization.i.e. time domain equalizer is perform...


Q) MIMO-OFDM and freq-domain equalization

Started by lsw00kor in comp.dsp10 years ago 1 reply

Hello, everyone. In SISO-OFDM, we usually employ a frequency domain equalization after the receiver FFT module, as a way to compensate for the...

Hello, everyone. In SISO-OFDM, we usually employ a frequency domain equalization after the receiver FFT module, as a way to compensate for the channel distortion along frequency bins. We depend on OFDM channel estimation and simple inversion for this purpose. In MIMO-OFDM, either multiplexed system or diversity system, what is the best way to implement a frequency-domain equalization for the...


Equalization using DFT

Started by jungledmnc in comp.dsp9 years ago 25 replies

Hi, I'm wondering, if there is no problem in equalization with DFT. Simply window the source signal, DFT, mutliply each frequency bin by a...

Hi, I'm wondering, if there is no problem in equalization with DFT. Simply window the source signal, DFT, mutliply each frequency bin by a real value defining it, and IDFT. This would even be zero-phase filtering wouldn't it? Or am I missing something? Thanks! dmnc


Equalization in satelleite channel

Started by tmoshe in comp.dsp11 years ago 11 replies

Does signal from geostationaric satellite need to be equalized? I'm talking about static receivers, not mobile. Because as far as I understand...

Does signal from geostationaric satellite need to be equalized? I'm talking about static receivers, not mobile. Because as far as I understand this channel, except for non-linear distorion due to high-power amplifiers, which does not affect M-PSK modulations, there are no other distortions that require equalization. Please help me with this!!! Thanks, Moshe


Channel order and matrix state of viterbi equalization

Started by Fan.Zhang in comp.dsp9 years ago 3 replies

Hi All, I am learning viterbi equalization to deal with ISI caused by multichannel effect. Let us denote L as the channel memory, that means...

Hi All, I am learning viterbi equalization to deal with ISI caused by multichannel effect. Let us denote L as the channel memory, that means we have L+1 channel taps. like this figure below. i.g. L=4 In --D--D--D--D-- | | | | | | | | | | h0 h1 h2 h3 h4 | | | | | | | | | | SIGMA | | Out When we...


Equalization in non-coherent systems

Started by Dan25 in comp.dsp4 years ago 4 replies

Hi, I have a general about the usage of equalization for non-coherent systems. I'm considering Differential PSK for a single carrier SISO...

Hi, I have a general about the usage of equalization for non-coherent systems. I'm considering Differential PSK for a single carrier SISO system. I consider different channels with different no., of taps. But I'm not sure what type of equalizer should be used for a such a system. Thanks. _____________________________ Posted through www.DSPRelated.com


Equalization in OFDM

Started by prabin in comp.dsp11 years ago

Hi guys, I was doing the simulations for the multitap frequency domain equalization for multicarrier system (DMT based). It seems though...

Hi guys, I was doing the simulations for the multitap frequency domain equalization for multicarrier system (DMT based). It seems though the at the band edges (First few tones and last few tones) higher performance can be achieved if we use higher number of equalizer taps. Can you people please suggest me any reasons why that happens or at least guide me to any publication that might hel...


Equalization without a training sequence

Started by HardySpicer in comp.dsp8 years ago 8 replies

I have seen many IEEE papers on what is now called Blind Equalization where a PBRS sequence is not needed for training. This is for...

I have seen many IEEE papers on what is now called Blind Equalization where a PBRS sequence is not needed for training. This is for muliple- channel (multivariable) problems. A colleague of mine says this is just academic rubbish and not used in practice. true or false and if true would there be any advantage? Hardy


relationship between time/frequency offset compensation and channel equalization

Started by minnows in comp.dsp9 years ago 2 replies

Hi, All i am really confused of these two concept. time/frequency offset will cause signal distortion but this distortion can be recoverd...

Hi, All i am really confused of these two concept. time/frequency offset will cause signal distortion but this distortion can be recoverd by channel equalization. what's the difference between time/frequency offset compensation and channel equalization? Thank you!


elementary question on channel equalization

Started by Bill Thomas in comp.dsp12 years ago 1 reply

Dear All, I'm new to DSP and channel equalization topic and kindly ask you about some fundamental questions: -If I want to send a binary...

Dear All, I'm new to DSP and channel equalization topic and kindly ask you about some fundamental questions: -If I want to send a binary data on an AWGN channel with ISI, how do I know at the receiver side, what was the sent information? Because it's easy to confuse -1 and 1.. -why it is good to send a training sequence at the beginning? -What is theoretical BER and why we can't ...


Audio Equalization Using MDCT

Started by foxcob in comp.dsp9 years ago 1 reply

I have done real-time audio equalization using fast-convolution (overlap-add) where the frequency domain values were specified by the end user...

I have done real-time audio equalization using fast-convolution (overlap-add) where the frequency domain values were specified by the end user through a graphical interface. If the phase response did not need to be specified, could a MDCT give better frequency resolution for around the same number of computations? Would this work or am I completely off here. Thanks, Jacob


adaptive equalization benefit

Started by mguo in comp.dsp12 years ago 4 replies

How much benefit can adaptive equalization really get you in a packet transmission system over multipath channel? Since one will need to...

How much benefit can adaptive equalization really get you in a packet transmission system over multipath channel? Since one will need to do synchronization before training the equalizer, it seems to me that synch will be the first one to fail most of the time if ISI is really serious. So that means you must have a synchronization scheme that can deal with serious ISI first. Or you will have to...


psychoacoustics of audio effects (dsp), equalization and filtering

Started by different in comp.dsp11 years ago 3 replies

I need to know what are the effects of sound alteration via dsp (reverb, echo, chorus, flanger...), filtering and equalization on persons. I...

I need to know what are the effects of sound alteration via dsp (reverb, echo, chorus, flanger...), filtering and equalization on persons. I searched with google and google Scholar but found very poor results. Does someone know where can I find such information?