Fractionally Spaced Equalizer

Started by zohreh in comp.dsp13 years ago 1 reply

Hi there, Is there anyone know how I can convert the coefficients of Fractionally-Spaced-Equalizer to the coefficients of...

Hi there, Is there anyone know how I can convert the coefficients of Fractionally-Spaced-Equalizer to the coefficients of Symbol-Spaced Equalizer? I know it can't be done by downsampling the output of this filter fed by Impulse input!


MLSE equalizer for optical communication

Started by zaman in comp.dsp6 years ago 7 replies

Hi, I want to do simulation on MLSE equalizer for optical QPSK/DQPSK signal first then i will go for experiment. I need Matlab file for that. I...

Hi, I want to do simulation on MLSE equalizer for optical QPSK/DQPSK signal first then i will go for experiment. I need Matlab file for that. I have read some recent papers on that but i dont understand the basic things of MLSE clearly for optical communication. Can anyone provide me any resources on MLSE equalizer. i really appreciate your help. BR// Zaman


non-integer fractionally spaced equalizer?

Started by Muzaffer Kal in comp.dsp13 years ago 3 replies

Hi everyone, I'm considering implementing a fractionally spaced equalizer and one question which has bugged me in the past is whether a...

Hi everyone, I'm considering implementing a fractionally spaced equalizer and one question which has bugged me in the past is whether a non-integer, smaller than 2 fractional spacing would have any benefits (ie better equalization). Suppose the signal rate is 100 M bauds and the signal bandwidth is around 70 Mhz. A T/2 fractional equalizer would need a 200 MHz ADC but would 140 MHz sampling ...


a question about map equalizer

Started by zqchen in comp.dsp13 years ago 4 replies

A question puzzled me for days, have to look for help here: > From the derivation of MLSE, a matched filter is obviously needed before the...

A question puzzled me for days, have to look for help here: > From the derivation of MLSE, a matched filter is obviously needed before the equalizer. Starting from continuous signal, the operation of matched filter and sampling is so natural. But so far as I read about MAP equalizer, I doubt the matched filter is needed no more. Or maybe I've missed something, at least it's not so clearly


relation of equalizer and channel coding

Started by buaawh in comp.dsp12 years ago 3 replies

Hello, Well known that decision-feedback equalizer is generally superior than linear equalizer, I was surprised to read the statement in a...

Hello, Well known that decision-feedback equalizer is generally superior than linear equalizer, I was surprised to read the statement in a paper: "Finally it is to mention that a combination of channel coding (Viterbi Decoding) and DFE did not lead to a performance gain compared to channel coding and linear equalization. It is well known that this combination represents a critical one..." ...


Audio equalizer!

Started by tasi in comp.dsp16 years ago 2 replies

Hi, Greeting, I am interesting with a fully digital audio equalizer. For I am a fresh in this field, I don't how to start. Does somebody can...

Hi, Greeting, I am interesting with a fully digital audio equalizer. For I am a fresh in this field, I don't how to start. Does somebody can tell me how to get/find a useful information? Thx


Graphic Equalizer

Started by Stacy in comp.dsp13 years ago 3 replies

I want to implement a graphic equalizer in S/W. I assume it is a bunch of bandpass filters with boost/cut at their respective frequencies. Has...

I want to implement a graphic equalizer in S/W. I assume it is a bunch of bandpass filters with boost/cut at their respective frequencies. Has anyone else done this or know of any links?


A que on LMS vs NLSM

Started by cpshah99 in comp.dsp10 years ago 2 replies

Hi All It is known from the books that NLMS is better than LMS when the dynamic range of the input signal to the equalizer is large. But...

Hi All It is known from the books that NLMS is better than LMS when the dynamic range of the input signal to the equalizer is large. But if we use an AGC before the equalizer and then use LMS to adapt the taps, what would be the performance compared to NLMS? Best Regards Chintan


equalizer with different location of the main tap

Started by zohreh in comp.dsp13 years ago 2 replies

Hi there, I simulate a system with upsampling 4 at the transmitter. Then, I use the equalizer and change the main tap. when I use different...

Hi there, I simulate a system with upsampling 4 at the transmitter. Then, I use the equalizer and change the main tap. when I use different location for main tap, the amount of timing error the receiver can beer is different and depends on the location of the main tap. Now, I realize that the timing error can change the group delay and equalizer can compensate for that. Is there anyone know...


timing recovery & equalizer latency

Started by kal in comp.dsp16 years ago 3 replies

Hi, I have a fully digital receiver where timing recovery and equalizer are adding significant latency and I would like to try and reduce it as...

Hi, I have a fully digital receiver where timing recovery and equalizer are adding significant latency and I would like to try and reduce it as much as possible. The timing recovery is done with a fractional delay filter (a farrow type FIR filter) where only one fractional value which gets multiplied by the outputs of the multi-branch fixed FIR filters is adapted. The equalizer is a fully ...


LMMSE equalizer

Started by Andrew2006 in comp.dsp14 years ago 3 replies

From some technical papers, I found out that non-adaptive MMSE block equalizer has been used to equalize for time-varying channels. Since adaptive...

From some technical papers, I found out that non-adaptive MMSE block equalizer has been used to equalize for time-varying channels. Since adaptive algorithm (LMS, RLS,....) is not applied here, then how the researchers simulate for the BER performance? Can anyone please help? Thanks.


cma equalizer

Started by Anonymous in comp.dsp14 years ago 9 replies

hello,erevyone.Recently I have been designing a blind channel equalizer based on the Constant Modulus Alogrithm.But I have a question that...

hello,erevyone.Recently I have been designing a blind channel equalizer based on the Constant Modulus Alogrithm.But I have a question that I can't think over.The question is as follows: The alogrithm I use is below: y(k)=3D =A1=C6f(k)x(N-k); % f(k+1)=3Df(k)-mu*e(k)*x(k); % e(k)=3D4*conj(y(k))*(abs(y(k))^2-R2); the transmitted signal is modulated by the QPS...


Linar & DFE Equalizer

Started by hisylee in comp.dsp12 years ago 2 replies

Hi guys Now I`m studying the Equalizer I`m coding the linear and dfe EQ but there is no different I don`t know what is wrong can...

Hi guys Now I`m studying the Equalizer I`m coding the linear and dfe EQ but there is no different I don`t know what is wrong can you correct this code or give me some idea %%%%DFE(Training+Direct) vs. Linear%%%% clear all; N=1000; % length of the information sequence K=5; actual_isi=[0.2, -0.15, 1.0, 0.21, 0.03]; sigma=0.01; delta=0.08; %0.08 delta2=0.00008;...


Matched filter and LMS equalizer

Started by Richard_K in comp.dsp14 years ago 2 replies

Hi, Is it possible for a LMS equalizer in multipath environment to achieve better BER performance as compared to matched filter in AWGN...

Hi, Is it possible for a LMS equalizer in multipath environment to achieve better BER performance as compared to matched filter in AWGN channel?


Specifications of an Equalizer

Started by rkthebad in comp.dsp15 years ago

Hello everyone, I owe my thanks to many of you for helping me implement my fixed-point graphic equalizer. I was trying to get its...

Hello everyone, I owe my thanks to many of you for helping me implement my fixed-point graphic equalizer. I was trying to get its characteristics/specifications in terms of its Frequency response, Signal-to-noise ratio and Total harmonic distortion. I came across this article http://www.rane.com/note145.html . Is this the best source? Or do you have any other suggestions? For SNR,...


Upsample, Downsample in the DSP audio Processing

Started by Kathy_pdx in comp.dsp5 years ago 14 replies

The audio system sample rate is 192 kbits/s. The DSP audio processing involves the ASIC hardware and DSP processor. Due to the...

The audio system sample rate is 192 kbits/s. The DSP audio processing involves the ASIC hardware and DSP processor. Due to the real-time constrains, the equalizer need be implemented at 16 kbits/s by a DSP processor. The routine way is to first down sample the audio signal to 16 kbits/s, design an equalizer, then apply the equalizer to the audio signal at 16 kbits. Then the equalized audio signal ...


Digital Equalizer Design for a Radio Receiver

Started by Anonymous in comp.dsp15 years ago 16 replies

Hi all, I am currently on a design of an equalizer for Medium/Short wave AM receiver. Problem statement: Medium /Short waver AM receiver...

Hi all, I am currently on a design of an equalizer for Medium/Short wave AM receiver. Problem statement: Medium /Short waver AM receiver suffers from sudden volume reduction irrespective of the Automatic gain control in receiver. How does this can be addressed. I am trying to control this audio reduction by an equalizer. But how does the actual reduction of audio in the radio program ...


interaction between bandpass equalizer and pll

Started by tmoshe in comp.dsp14 years ago 4 replies

Hi, When using the SG algorithm for equalizing, the error signal is computed at the end of the pll. My problem is that the pll cannot be locked...

Hi, When using the SG algorithm for equalizing, the error signal is computed at the end of the pll. My problem is that the pll cannot be locked before the channel is reasonably equalized. Thus, I have a "bootstrap" where the equalizer need phase information(from pll) and the pll need equalized signal in order to work properly. I still have not simulated this situation, so I need your experience...


interaction between bandpass equalizer and pll

Started by tmoshe in comp.dsp14 years ago 1 reply

Hi, When using the SG algorithm for equalizing, the error signal is computed at the end of the pll. My problem is that the pll cannot be locked...

Hi, When using the SG algorithm for equalizing, the error signal is computed at the end of the pll. My problem is that the pll cannot be locked before the channel is reasonably equalized. Thus, I have a "bootstrap" where the equalizer need phase information(from pll) and the pll need equalized signal in order to work properly. I still have not simulated this situation, so I need your experience...


equalizer error bias

Started by mk in comp.dsp13 years ago 2 replies

Hi, I have a channel with significant ISI with a 3 level (1,0,-1) transmission. The transmitted data and the receiver data after quantization...

Hi, I have a channel with significant ISI with a 3 level (1,0,-1) transmission. The transmitted data and the receiver data after quantization have zero mean. The problem is that the error output of the equalizer after convergence is not zero mean even (it's slightly positive) though its variance is very low (around 22dB below signal power). It's been pointed to me that it should be zero mean...