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# Time Selective

23 Threads found on edaboard.com: Time Selective

## Doubly selective channel

Hi, How to make matlab program for doubly selective channel? I know by using Jake's model or Clrack's model but in this case the resulting channel in time domain represents as a matrix where its columns represent the length of transmitted signal and its rows represent the number of path. Is there any method to generate the channel impulse respon

## Selective DC power supply

Hello, I am looking for a module that selects automatically between the main power supply (DC supplier), and the backup supply (battery) when my main source is off. I tried searching for mini power converters or BMS but didn't find what i needed. If i had more time I would design one myself, but I'm affraid i don't have the time needed (maybe

## Need for Space-Time Trellis Coded OFDM system performance analysis in Matlab

Hi all, I am trying to implement STTC-OFDM (2Tx-1Rx) over frequency selective channels(2-taps or 3-taps and so on). I need a modification on my code over single tap quasistatic flat fading environment. My question is how can I use the channel impulse response for multiple tap channels on the maximum likelihood decoder to calculate branc metrics.

## OFDM with ICI Frequncy Equalization

Hello, I have an OFDM system over a time varying frequency selective channel, which means I have ICI at the receiver side. I am dealing with the ICI using linear frequency equalizer like MMSE. Without ICI equalization, there is an error floor in the ABER vs. SNR. With ICI equalization, the curve decays well until a certain SNR point, and then it

## MATLAB Help: Continous Time Frequency Selective Channel

Hello all, I have the following frequency selective channel: h(\tau;t)=\sum_{p=0}^{N_p}h_p\delta(t-\tau_p) and the transmitted signal in the passband is given by: s(t)=\Re\left\{\sum_{k=-L}^{N-1}d_kg(t-kT_s)e^{j2 pi f_ct}\right\},\,\,\,t\in I want to derive the discrete time model from these equation

## How to generate a time-varying channel

Hi all; I would like to generate a discrete-time time-varying multipath (doubly selective) channel. How can I do that? Also, I need the power delay profile of the multipath channel to decay exponentially. Any help will be highly appreciated. Thanks

## What's the differencce between fast flat fading and slow flat fading?

Fast vs. slow is in the time domain, whereas flat vs. selective is in the frequency domain. 1- If the channel changes withing a symbol time it is fast. Otherwise it is not fast. 2- If the channel frequency response is constant over the signal bandwidth then it is flat. Otherwise, it is frequency selective. Refer to (...)

## How to generate time varying channel?

Hello, How to generate a time varying frequency selective channel of length L+1 in MATLAB, such that the nth received symbol is given by: y(n)=\sum_{l=0}^Lc(n;l)x(n-l)+\eta(n) Thanks in advance

## Selective sampling and SNR

I am building an optical OOK (On off Key Ring) system without a carrier frequency. . Essentially, the presence of signal indicates one and lack of it indicates zero. I have a precise clock that is synced with transmitter. The

## frequency selective channel

Fading means that the channel is time variant. Fading can be time variant or time invariant. time variant versus time invariant depends on doppler spread (usually affected by mobility). Fading versus non fading depends on presence of reflectors. Frequency selectivity means that the impulse response

## What is signal fading and how it affects cooperative wireless communication?

Fading is the fluctuation of power transmitted by the transmitter due to the time variant channel that exhibits environmental effects, fading is NOT multi-path (this is a famous fallacy). Fading may be frequency selective or flat.

## rayleighchan usage in MATLAB for Rayleigh channel

Hello, I would like to know some notes about using rayleighchan in Matlab in generating a frequency selective Rayleigh channel. In the transmitter, Ts=1e-6; % sample time of the input signal, in seconds Fd=40; % maximum Doppler shift, in Hertz TAU=; % row vector of path delays, each specified in seconds PDB=

## Confused to use ADC in ATMEGA8 Series Microcontroller

When the time gap between the acquisitions is 10-30 sec then you should use selective Mode, you may halt he CPU during the data acquisition to have a better noise immunity.

## more via overlap of metal

Thick metal is usually etched using wet chemicals rather than Plasma due to the time it would take to plasma etch and the fact that the chemistry used for plasma metal etch is not very selective to the resist mask, so a very thick resist would be required which is not really feasible. The wet chemical etch etches isotropically so it etches sideway

## simulink delay spread - how to use in a spectre simulation

You can use the worst case scenerio based Delay spread. If you want to simulated Flat fading the time delay of the multipath components should be very less (atleast 100 time smaller than the symbol time). If you want to simulate Freq-selective fading, just make sure that the delay of the multipath components is larger or (...)

## RF Transmission & Receiving Questions

There is no way to send RF energy to selective device only. Any other RF device will get at least part of RF energy. There are some methods to separate devices. It may be frequency division or time division as the easiest methods. Some kinds of spread spectrum signals are also possible like UWB, TDMA, CDMA, OFDM, etc. The best choice will depend on

## channel modeling for mimo sytems..please help urgently

i want to produce a GUI in matlab that 1.shows recieved signal envelope for mimo channel in flat fadig and frequency selective channel(signal strength against time) 2.shows improvement in capacity as number of transmit and recieve antennas changese.g 1*1,2*3,etc 3.shows inmprovement in fade margin as number of transmit and recieve antennas chang

## Selective bit blasting of verilog netlist withDesignCompiler

Can anyone tell me if there is anyway to tell DC to do selective bit blasting of verilog netlist. Actually I want to bit blast some buses in my design but at the same time I want to avoid bit blasting of some other buses in some macros. Is there any variable I need to use to achieve this.

## State space domain in Matlab ----- Please help me!

Hi, Do you want to use it for signal detection/equalization in fading channel? If yes for what kind of channel (I mean frequency selective/time varying or what?) state space equations depend on kind of application you want. so for different scenarios state space equation differ? regards

## Impulse response of fading channel and channel estimation

I am facing very fundamental problem in channel estimation in wireless communication. In channel estimation we usually find the impulse response of channel. But what will be the impulse response of frequency flat/selective fading channel (time varying/time invariant)? and how will it be different from impulse response of a non-fading (...)