Constant modulue equalization for FSK signals

Started by john in comp.dsp16 years ago 1 reply

Hi group, I have a simulation in which a noisy binary CPFSK signal is filtered with a FIR filter representing the channel. Due to the channel,...

Hi group, I have a simulation in which a noisy binary CPFSK signal is filtered with a FIR filter representing the channel. Due to the channel, the BER curve shifts to the right. I'm trying to construct a blind equalizer for CPFSK using the Constant Modulus (CM) criterion operating on a block of data. Normally the CM criterion is applied in a recursive way to update a gradient descent al...


Question about RS code

Started by fl in comp.dsp16 years ago 4 replies

Hi, In my research project(Single Carrier-Frequency Domain Equalization), I have a channel decoded data stream which is modulated/demod in...

Hi, In my research project(Single Carrier-Frequency Domain Equalization), I have a channel decoded data stream which is modulated/demod in QAM64 form. The error is characterized as burst type due to error propagation. Most error burst length is 4 QAM64 symbols. First, I don't want to use interleaving. This is because we want to do a comparative study. Multi-block interleaving will be unf...


Re: Allpass Filter Matlab Functions

Started by Jerry Avins in comp.dsp17 years ago

Juha wrote: ... > See > > P. Regalia and S. Mitra, "Tunable digital frequency response > equalization filters," IEEE Trans. Acoust.,...

Juha wrote: ... > See > > P. Regalia and S. Mitra, "Tunable digital frequency response > equalization filters," IEEE Trans. Acoust., Speech, Signal Processing, > Vol. 35, No. 1, pp. 118-120, Jan 1987 > > Juha I haven't seen the paper yet, but the title implies altering the frequency response. How might that be done with all-pass filters? My remark about needing two breaks to c


estimation of SNR using MEDLEY

Started by manish in comp.dsp16 years ago 4 replies

hi, i am fresh in the field of ADSL/ADSL2 modems. our system has 2-stage equalization - Time-domain equalizer for reducing ISI to within the...

hi, i am fresh in the field of ADSL/ADSL2 modems. our system has 2-stage equalization - Time-domain equalizer for reducing ISI to within the cyclic prefix, and Frequency-domain equalizer which is a 1-tap equalizer to undo the channel. for training the TEQ, a signal called REVERB is used, a psuedo-random signal which is identical from one symbol to the next. for training the FEQ and estimating...


A question on practical receiver

Started by cpshah99 in comp.dsp11 years ago 33 replies

Hi Guys At the transmitter side, the complex base-band signal is modulated using a high frequency carrier, amplified and transmitted. At...

Hi Guys At the transmitter side, the complex base-band signal is modulated using a high frequency carrier, amplified and transmitted. At the receiver it is first passed through a bandpass filter to remove out of band noise, and then reverse processing is applied i.e. down conversion to base-band, matched filter, synchronization, equalization etc... The question will definitely sound stu...


need help - converting from a Frequency spectrum to a FIR filter

Started by Anonymous in comp.dsp16 years ago 5 replies

Hello, Im doing a room equalization project, at the moment by sweeping the room with sine waves, and getting the frequeuncy response of the...

Hello, Im doing a room equalization project, at the moment by sweeping the room with sine waves, and getting the frequeuncy response of the room. I now have to convert from this 'room information' to a FIR filter (and then an inverse FIR filter) that will be applied to sound sources to compensate for the response of the room. Any ideas anyone? How to get from FFT (magnitude and phase i...


Acoustic room response - measurement and interpretation

Started by Larry McFarren in comp.dsp18 years ago 14 replies

I'd like to get your suggestions on a good way to look at acoustic room response for purposed of equalization. I'm thinking that I can play...

I'd like to get your suggestions on a good way to look at acoustic room response for purposed of equalization. I'm thinking that I can play some wideband tones, which get recorded into a PC via a microphone. Does anyone have any suggestions on the tones that would be good to use? Once the data is recorded in my PC, what type of processing needs to take place to 'characterize' the ro...


Does diversity helps channel tracking?

Started by buaawh in comp.dsp13 years ago 1 reply

Hello, Recently I read a...

Hello, Recently I read a paper http://calypso.unicauca.edu.co/gntt/grupo/maestria/MaterialBandaAnchaInalambrica/channel_models/ 1385clar.pdf The result is: with receiver diversity, adaptive RLS frequency-domain equalization(and channel tracking) can track speed up to 100 miles/hour, while its signle antenna counterpart has poor tracking capability. I wonder why diversity can improve tracking.


relation of equalizer and channel coding

Started by buaawh in comp.dsp13 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..." ...


Channel Equalization

Started by rider in comp.dsp18 years ago 3 replies

Hi! I want to add a channel equalizer into my my BPSK receiver. I have a confusion where to place this module. Either in pass-band or...

Hi! I want to add a channel equalizer into my my BPSK receiver. I have a confusion where to place this module. Either in pass-band or in base-band? Currently my receiver performs following sequence of events: 1) The received pass-band signal r(t) is sampled at Fs (8 times the symbol/bit rate fb) and demodulated using a Costas Loop carrier recovery and LPF. This LPF filter gives a base-b...


Help for references in Proakis's "Digital Communications"

Started by Anonymous in comp.dsp17 years ago 1 reply

Hi, I once read Proakis's "digital communications", 2000 version. Now I have one notes of Page 638, which said about the references: the...

Hi, I once read Proakis's "digital communications", 2000 version. Now I have one notes of Page 638, which said about the references: the papers by George et al. (1971), Price(1972), Salz(1973) and Proakis (1975). The contents are about decision feedback equalization. I cannot borrow this book from library until 15, March. I only find the reference title of Price(1972) by internet. Could an...


Ideas for DSP project

Started by Guillermo in comp.dsp18 years ago 3 replies

Hello!, I'm looking for ideas to make a dsp project for an undergraduate course in the university, it should be made in about a month, it could...

Hello!, I'm looking for ideas to make a dsp project for an undergraduate course in the university, it should be made in about a month, it could be something like an echo canceller, noise canceller, vocoder, audio equalization, or could be also something like digital control of the speed of a DC engine using a dsp, I cannot use this ideas to make my project because they had been made in previo...


Equalization is necessary in OFDMA-PHY?

Started by ryujin_ssdt in comp.dsp15 years ago 2 replies

I have a little Matlab simulation for a OFDMA-PHY tranceiver based on the 802.16e standard. The BER results over a simple AWGN channel using a...

I have a little Matlab simulation for a OFDMA-PHY tranceiver based on the 802.16e standard. The BER results over a simple AWGN channel using a QPSK constellation coincide with those of a single carrier QPSK. With this I assume my code is correct. The problem is that once I add a rayleigh fading channel to the simulation the BER values stay high (0.5) for all SNR values. This of course does not ...


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 ...


OFDM cyclic prefix/Equalization question

Started by ramsay in comp.dsp15 years ago 4 replies

Hi, I am working on a uncode 16-QAM OFDM simulation. The simulation works fine when used in AWGN channel. I have a couple of questions now...

Hi, I am working on a uncode 16-QAM OFDM simulation. The simulation works fine when used in AWGN channel. I have a couple of questions now when i am simulating performance in multipath channels. 1) What I want to understand through simulation is the effect of cyclic prefix length on performance in a multipath channel. For example consider that the channel impulse response is [0.7071 0 ...


Rician channel modelling

Started by cpshah99 in comp.dsp13 years ago

Hi Recently I found a paper, which describes how to model rician multipath channel. The paper is 'Estimation and equalization of...

Hi Recently I found a paper, which describes how to model rician multipath channel. The paper is 'Estimation and equalization of multipath ricianfading channels with stochastic tap coefficients' - Bor sen chen et al. In that paper, the channel is modelled as: h_k(n)=h_k+s_k(n), where index k is for multipath and n is for time. where h_k is non zero constant mean and s_k(n) is WSSUS ...


problem understanding LMS noise whitening alg.

Started by samwo123 in comp.dsp14 years ago

Hi. I am self-studying adaptive signal processing. I've read C.R. Johnson's Adaptive Signal Processing, and some parts of Haykin's. I am...

Hi. I am self-studying adaptive signal processing. I've read C.R. Johnson's Adaptive Signal Processing, and some parts of Haykin's. I am reading this paper "Self adaptive decision feedback equalization: Application to high order QAM signal" In the paper, adaptive whitening filter is applied to the received signal. The whitened signal is then fed to another adaptive FFE equalizer to recov...


Channel equalization for MSK

Started by Vikram Chandrasekhar 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...


Frequency domain interpolation Question

Started by buaawh in comp.dsp13 years ago 3 replies

This problem comes from my simulation of Single Carrier Frequency Domain Equalization(SC-FDE) system. Suppose the symbol rate is Ts, for reason...

This problem comes from my simulation of Single Carrier Frequency Domain Equalization(SC-FDE) system. Suppose the symbol rate is Ts, for reason of pulse shaping filtering I perform fractional space sampling with sample rate Ts/2. A FFT block length is 512 and the pilot(used for channel estimation) length is 64. Channel estimation is done as follows: (1) use length 64*2(sampling rate Ts/2) pi...


Delay estimation

Started by Vladimir Vassilevsky in comp.dsp11 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...