## Definition for transversal equalizers

Started by in comp.dsp17 years ago 21 replies

Hello Everyone, Can anyone point me the definition for a transversal equalizer? Some books only treat linear and adaptive equalizers, and some...

Hello Everyone, Can anyone point me the definition for a transversal equalizer? Some books only treat linear and adaptive equalizers, and some talk about transversal equalizers. It seems that all linear equalizer are transversal equalizers but I not convinced that this is true and I do not know if the opposite holds as well!? Very confused!! Pointers to references are also appreciated. ...

## Equalizers implemented in GSM receivers

Started by in comp.dsp8 years ago 6 replies

Hi All, I need some specific information on channel equalizer implementations of practical GSM receivers. I assume time domain equalizers are...

Hi All, I need some specific information on channel equalizer implementations of practical GSM receivers. I assume time domain equalizers are used in GSM phones, but I would like to the equalizer algorithms and training algorithms and convergence algorithms used by them. I highly appreciate if anyone can share his/her experience on this regard. All the references are highly appreciated. ...

## BER of multipath channel

Started by in comp.dsp15 years ago 4 replies

I wrote a program to calculate the BER of LMS equalizer in AWGN and multipath channel. The tap weights of the mobile radio channels...

I wrote a program to calculate the BER of LMS equalizer in AWGN and multipath channel. The tap weights of the mobile radio channels are normalized to 1 (the exact value is 1.0062). Surprisingly, I found out that the performance of the equalizer in multipath channel is better than the one in AWGN. Is this acceptable? Or anything that might be wrong in my simulation? Or the performance gain of ...

## Interpolated Constant-Q Equalizer

Started by in comp.dsp15 years ago 36 replies

Hello, We are implementing DSP based 31 band 1/3 octave audio graphic equalizer on programmabele DSP. The customer specifications demand...

Hello, We are implementing DSP based 31 band 1/3 octave audio graphic equalizer on programmabele DSP. The customer specifications demand for an Interpolated Constant - Q topology. For the implementation we are basing our design on Rane's Dennis Bohn paper on AES ("Constant-Q Graphic Equalizers", JAES Volume 34 Number 9 pp. 611-626; September 1986). Although the topologies suggested on the ...

## How to design a graphic equalizer

Started by in comp.dsp17 years ago 6 replies

I am doing a software project about a ten-band graphic equalizer. Is there any solutions about how to design it? Currently, I have the...

I am doing a software project about a ten-band graphic equalizer. Is there any solutions about how to design it? Currently, I have the following ideas: 1.Use FFT, apply different gains to each frequency bin. But for low frequency band like 31.25Hz, 62.5Hz, 125Hz, there are few frequency bins even using large length FFT. The frequency precision is roughly influencing. 2.Use FIR filter bank. D...

## How to design a graphic equalizer

Started by in comp.dsp17 years ago 1 reply

I am doing a software project about a ten-band graphic equalizer. Is there any solutions about how to design it? Currently, I have the...

I am doing a software project about a ten-band graphic equalizer. Is there any solutions about how to design it? Currently, I have the following ideas: 1.Use FFT, apply different gains to each frequency bin. But for low frequency band like 31.25Hz, 62.5Hz, 125Hz, there are few frequency bins even using large length FFT. The frequency precision is roughly influencing. 2.Use FIR filter bank....

## Ungerboeck metric for MLSE Equalizer

Started by 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...

## Timing adjustment and equalizer in a modem

Started by in comp.dsp12 years ago 3 replies

Hi all, I have a question on timing adjustment and equalizers, and in my case the application is for a simple low speed PSK modem. I am using...

Hi all, I have a question on timing adjustment and equalizers, and in my case the application is for a simple low speed PSK modem. I am using a half-symbol spaced passband complex equalizer, so basically we are pumping samples at B/2 (B is the baud rate). There is no preceeding interpolator, and the sample rate is not locked to the symbol rate. Now, I am also using a Gardner-type timing e...

## Implementing a graphic equalizer on speech

Started by in comp.dsp18 years ago 4 replies

I'm a bad with signal processing but an experience c++ programmer. I have implemented a code on a real-time man's speech that makes a pitch...

I'm a bad with signal processing but an experience c++ programmer. I have implemented a code on a real-time man's speech that makes a pitch change. The algorithm works fine in the time domain and implements overlapping windows(50% overlapping). Now I want to add a graphic equalizer and use the same blocks for that. I was told that implementing an fft procedure on the blocks with a variable f...

## Linear-phase FIR filter coefficient properties

Started by in comp.dsp12 years ago 50 replies

Hello, I have some unclear points about FIR filter coefficients which I would like to get some help on. First, what I want to do is to...

Hello, I have some unclear points about FIR filter coefficients which I would like to get some help on. First, what I want to do is to design a simple pre-equalizer for a DMT system. I have the frequency transfer function (magnitude) of the channel and want to design a pre-equalizer for that. I have been reading "Understanding Digital Signal Processing - Lyons", "Digital Signal Processing...

## Real-time Tunable Digital Music Equalizer and Amplifier

Started by in comp.dsp12 years ago 3 replies

Can anyone tell how to create Real-time Tunable Digital Music Equalizer and Amplifier implementing it using the IIR. Thx in advance. Guna.K.

Can anyone tell how to create Real-time Tunable Digital Music Equalizer and Amplifier implementing it using the IIR. Thx in advance. Guna.K.

## Minimization of phase error fluctuation in OFDM equalizer

Started by in comp.dsp13 years ago 2 replies

I am designing ofdm equalizer.Ofdm frame contains: -19 symbols -24 subcarriers per channel -pilot symbols that are comb type arranged -BPSK...

I am designing ofdm equalizer.Ofdm frame contains: -19 symbols -24 subcarriers per channel -pilot symbols that are comb type arranged -BPSK modulation The period of one frame (19symbols) is 625us,pilots are inserted every four symbol in time direction and every four subcarrier in frequency direction. I made real measurements to determine the channel nature between base station and rece...

## LMS Equalizer fo SC_FDE

Started by in comp.dsp14 years ago 2 replies

Hi All, I am trying to simulate a SC-Frequency domain LMS equalizer. Now since it is SC the detection has to be in time domain although...

Hi All, I am trying to simulate a SC-Frequency domain LMS equalizer. Now since it is SC the detection has to be in time domain although the channel estimation is in frequency domain so i follow these steps 1) Multiply data -> data_f (in frequency domain) with weights in frequency domain 2} Convert data in time domain data_t by ifft and pass it through detector. 3) compute the error (det

## Channel equalization for MSK

Started by in comp.dsp18 years ago 4 replies

Hello, I am trying to set up an adaptive LMS adaptive equalizer to apply the equalizer on a phase modulated signal eg: MSK. For modulation...

Hello, I am trying to set up an adaptive LMS adaptive equalizer to apply the equalizer on a phase modulated signal eg: MSK. For modulation schemes such as PSK/QAM, the effect of a channel filter leads to severe ISI and hence channel equalizers are very important. Further, they have been extensively documented and well-studied. How severe is the effect of a channel filter on a MSK type si...

## Delay estimation

Started by in comp.dsp12 years ago 6 replies

Hello All, There is a communication channel with nonminimum phase response. The channel could be described as H(s)=P(s)/Q(s). The channel is...

Hello All, There is a communication channel with nonminimum phase response. The channel could be described as H(s)=P(s)/Q(s). The channel is equalized by a linear equalizer. The equalization is near perfect but there is a delay lag in the (equalizer + channel) due to the nonminimum phase part of the response. What would be an efficient way to estimate this delay lag, knowing the equal...

## branch metric of MLSE equalizer for GSM

Started by in comp.dsp14 years ago 2 replies

Hi All, I am reading an article about GSM MLSE equalizer. The article link is here. http://www.freescale.com/files/dsp/doc/app_note/AN2943.pdf?fpsp=1&WT_TYPE=Application%20Notes&WT _VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation This article is quite brief, and I have two questions here 1) is the Equation 6 in the article correct? 2) How can I get Equation 6 from Equation 5

## T/2 -spaced FSE MMSE equalizer, with carrier offset

Started by in comp.dsp16 years ago 10 replies

Hi, here I am now doing a project about T/2 -spaced FSE MMSE equalizer based on the stochastic gradient algorithm. I use training symbol...

Hi, here I am now doing a project about T/2 -spaced FSE MMSE equalizer based on the stochastic gradient algorithm. I use training symbol method to update the coefficient. It seems working well in some channel distortion enviroment. However, when carrier offset exists, i.e. (the constellation of QAM rotates), this algorithm doesn't converge, even I force the update coefficient steps very...

## questions about gmsk and equalizer

Started by in comp.dsp15 years ago 2 replies

1. Though dummy bits are assumed before and after tail bits, they are not actually transmitted on the air, are they? Then since the...

1. Though dummy bits are assumed before and after tail bits, they are not actually transmitted on the air, are they? Then since the gaussian pulse is assumed to last 4 bits, will the dummy bits lag into the tail bits in real signal? 2. If dummy bits are not transmitted, then how does the equalizer handle it if there are more taps than the number of tail bits? Thanks a lot!

## low frequency response of adaptive equalizer?

Started by in comp.dsp16 years ago 12 replies

Hi, I have an LMS based adaptive equalizer which mostly works well but it doesn't tolerate low frequency inputs too well. The channel...

Hi, I have an LMS based adaptive equalizer which mostly works well but it doesn't tolerate low frequency inputs too well. The channel consists of two transformers (high pass) and cable (low pass) and when there is long periods of no-change in data (which is possible unfortunately even though the data is scrambled) and the SNR goes down during these long periods of no change. I think this is ...

## How to get the expected value of the transmitted signal?

Started by in comp.dsp15 years ago 1 reply

Hi,all I would like to find the expected value of my OFDM transmitted signal. As Y= H*X + N Y= Received Signal , H = Channel , X=...

Hi,all I would like to find the expected value of my OFDM transmitted signal. As Y= H*X + N Y= Received Signal , H = Channel , X= transmitted signal ,N=noise Since i need to generate a MMSE equalizer, i need to find the Expected value of X , in order to do the simulation. The algorithm of MMSE equalizer is Gmmse= Ru * Transpose(H) * inv(Rn+ H * Ru * Transpose(H)) Where Ru ...