IQ Receiver Processing

Started by Ali A Nasir in comp.dsp12 years ago 18 replies

Can anyone please tell me one thing that in communication receiver, after performing matched filtering and timing recovery seperately for I...

Can anyone please tell me one thing that in communication receiver, after performing matched filtering and timing recovery seperately for I and Q data, whether equalization works separately on I and Q data or we first get the complex signal (combining I and Q) and perform equalization on complex signal (or what is preferable) ? I am sorry for if this question is silly but its my first que...


equalization of 'non-continuous' sample

Started by cl7teckie in comp.dsp12 years ago 2 replies

I am trying to build a 'non-continuous' 12-tap FFE (LMS Blind) equalizer in software, hoping to remove to some extent group delay in a satellite...

I am trying to build a 'non-continuous' 12-tap FFE (LMS Blind) equalizer in software, hoping to remove to some extent group delay in a satellite link. I am doing in software, as I am ONLY keen to know the SNR after equalization. The reading are in chunks of 512 x I/Q samples. Technically, does this even work, due to the fact that it is non-continuous. I do not need a perfect system, just some ...


DPSK's relation with OFDM and Demodulation

Started by karthikbalaguru in comp.dsp14 years ago 2 replies

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...

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 as DPSK / DQPSK if applied to each sub-carrier, equalization can be completely omitted. ( Reason - ...


Low SNR receiver design

Started by commsignal in comp.dsp9 years ago 12 replies

Hi All, I would be very grateful if some experts can give me their opinions about the following questions (from algorithmic...

Hi All, I would be very grateful if some experts can give me their opinions about the following questions (from algorithmic perspective). (1) What has been/can be a good approach to a single carrier receiver design (synchronization, channel estimation, equalization, etc.) operating at low SNRs? How would you go about frquency, timing, phase synchronization and equalization algorithms? (3) ...


Turbo Equalization

Started by sair...@gmail.com in comp.dsp15 years ago

Hi, I am working on Turbo Equalization based on MMSE-SC based techniques. I have a question on choosing the chnanel code....

Hi, I am working on Turbo Equalization based on MMSE-SC based techniques. I have a question on choosing the chnanel code. All papers which people refer uses convolutional codes decoded by using SOVA. Is there any reason why we use convolutional codes rather Turbo codes ? Any suggestion on this is highly appreciated. Best Regards, -SaiRamesh.


Dynamic equalization / Multi-band compression

Started by mavavilj in comp.dsp6 years ago 1 reply

How does one construct a dynamic eq or a multi-band compressor. E.g. something like...

How does one construct a dynamic eq or a multi-band compressor. E.g. something like http://www.meldaproduction.com/plugins/product.php?id=MDynamicEq The naive approach would be to have filters and then create envelopes to control the gain of any such filter. Then I've heard about using allpass filtered signal to mix into the "dry" signal and perform dynamic equalization that way. However th...


MMSE and ZF equalization in OFDM systems

Started by Dan25 in comp.dsp7 years ago 5 replies

Hi, What is the performance difference of MMSE equalizer and ZF equalizer in a OFDM system. I have simulation 3 tap Rayleigh channel for QPSK...

Hi, What is the performance difference of MMSE equalizer and ZF equalizer in a OFDM system. I have simulation 3 tap Rayleigh channel for QPSK ODFM system and found out that both the equalizers give the same performance. But in Single carrier Frequency Domain Equalization, MMSE performs significantly better than ZF. Can anyone please advice me in this regard. Thanks in advance. _...


ask help on viterbi equalization

Started by Fan.Zhang in comp.dsp12 years ago 6 replies

Dear All, I am learning how to use viterbi in GSM Channel Equalization. As a newer, I have some basic questions about this method. Q1, What...

Dear All, I am learning how to use viterbi in GSM Channel Equalization. As a newer, I have some basic questions about this method. Q1, What I learn from textbook, viterbi can handle bit sequence with some mistakes, and output correct bit sequence. How can it handle complex data inputs? Because the received signal are complex. Q2, Can you kindly introduce some papers with simple math deriv...


lowpass resonant filter sweeping and peak equalization?

Started by tpytel in comp.dsp17 years ago 19 replies

Hi all, it seems like there are some fairly knowledgeable people hanging out here, so I will try my luck after searching high and low on the...

Hi all, it seems like there are some fairly knowledgeable people hanging out here, so I will try my luck after searching high and low on the net. I am working on audio synthesis and am stuck on a couple of things with my 2 pole lowpass resonant IIR filter (it is a standard conjugate pole pair thingy for dealing with real signals of course :) The first thing is peak level equalization. The f...


Paper on LMS adaptive equalization

Started by Alberto in comp.dsp16 years ago 4 replies

I am in search of the PDF of this paper : "Efficient realization of asynchronous LMS adaptive equalization" by Jan W.M. Bergmans I have...

I am in search of the PDF of this paper : "Efficient realization of asynchronous LMS adaptive equalization" by Jan W.M. Bergmans I have been unable to find it with Google, nor to find an email address for the author. Does anybody have it ? Can you send it to my email address dibene @ usa.net (remove the spaces surrounding the @ symbol) Thanks in advance Alberto


[Enquiry] how to add OFDM subcarriers in simulink

Started by Anonymous in comp.dsp14 years ago 4 replies

I am doing a project on OFDM equalization. So far, i have been doing equalization for one ofdm symbol. I wish to ask how could i add...

I am doing a project on OFDM equalization. So far, i have been doing equalization for one ofdm symbol. I wish to ask how could i add more subcarriers in by using Simulink? Is there any example that i can refer to? Thanks alot.


Ungerboeck metric for MLSE Equalizer

Started by Pave...@gmail.com in comp.dsp14 years ago 3 replies

Hello. Who can give me some description about Ungerboeck MLSE equalizer? I use it for GSM burst equalization and get strange result - it...

Hello. Who can give me some description about Ungerboeck MLSE equalizer? I use it for GSM burst equalization and get strange result - it works bad. BER is increased as comparision with no equalization. I estimate Channel Impulse Response and use it for signal reconstruction in eaualizer but it works bad. So I make symbol-by-symbol decisions. Can you guide me to additional information about M...


phase equalization of time-delayed signal

Started by toneburst in comp.dsp11 years ago 3 replies

Hi, Here is an audio signal processing problem that I have not been able to find an answer to: I would like to analyze the effects of adding...

Hi, Here is an audio signal processing problem that I have not been able to find an answer to: I would like to analyze the effects of adding a delayed version of a signal to itself, while having the delayed signal in-phase with the non-delayed signal. Essentially, I'd like to "undo" phase rotation caused by (fixed) time delay, using some sort of phase equalization filter. This would only b...


Wiener solution for equalization

Started by Richard_K in comp.dsp15 years ago 4 replies

In order to find the Wiener solution for equalization purpose, do I need to provide delay to the desired signal as in the case of LMS...

In order to find the Wiener solution for equalization purpose, do I need to provide delay to the desired signal as in the case of LMS algorithm? Will the result of the Wiener solution become better if I provide some delay to the desired signal? Thanks.


New algorithms in MLSE?

Started by Verictor in comp.dsp8 years ago 6 replies

Hi, Anyone is aware of state search algorithms in MLSE (maximum likelihood sequence equalization) other than the Viterbi? Thanks

Hi, Anyone is aware of state search algorithms in MLSE (maximum likelihood sequence equalization) other than the Viterbi? Thanks


Turbo Equalization

Started by Aitezaz in comp.dsp10 years ago

I have the following outputs at the various iterations in Turbo Equalization. Iteration No. 1 -> Error at the output of BCJR = 16, Error at...

I have the following outputs at the various iterations in Turbo Equalization. Iteration No. 1 -> Error at the output of BCJR = 16, Error at the output of ECC= 105 Iteration No. 2 -> Error at the output of BCJR = 8, Error at the output of ECC= 51 Iteration No. 3 -> Error at the output of BCJR = 6, Error at the output of ECC= 88 Iteration No. 4 -> Error at the output of BCJR = 6, Error


equalization

Started by CDMA2000 in comp.dsp16 years ago 2 replies

I am working on a project designing linear decision feeback equalizers. I would greatly appriciate any links that will help me learn more...

I am working on a project designing linear decision feeback equalizers. I would greatly appriciate any links that will help me learn more about linear equalizers and different methods used for equalizations such as (MSE,BER,adaptive equalizers...etc) thank You


Equalization

Started by Anonymous in comp.dsp8 years ago 15 replies

There is a large literature on estimating and equalizing comms channels with everything from LMS to higher order stats. It occurred to me, why not...

There is a large literature on estimating and equalizing comms channels with everything from LMS to higher order stats. It occurred to me, why not just fire an impulse or string of them into the channel instead and then average the result. That would give you the coefficients of a ma model whether it is min or nm phase. I assume the problem is noise but that too should average out.


Need of Eqaulization ?

Started by mite_learner in comp.dsp8 years ago 31 replies

Dear Members, I am experimenting on digital 4-FSK (orthogonal) communication system. On the demodulation side, I am using AGC and then 4...

Dear Members, I am experimenting on digital 4-FSK (orthogonal) communication system. On the demodulation side, I am using AGC and then 4 filters to detect tones and then using symbol timing. My question is how can I know that I need equalization looking at the signal if I transmit and receive the signal over the air? How can I verify that my signal is being affected by multipaths ? ...


ML equalizer

Started by sair...@gmail.com in comp.dsp15 years ago

Hi, I am working on equalization schemes without using Viterbi type of algorithms. Assume that complexity is not an issue. I am trying...

Hi, I am working on equalization schemes without using Viterbi type of algorithms. Assume that complexity is not an issue. I am trying to detect the received samples using ML equation. Mathematically , if a1, a2, a3 .. aN are the input symbols, say h1, h2, h3 are the channel tap gains. Then the received signal is represented in vector fom as R= A*h+n, where R is the received vector...