## Forums Search for: Oversampling

## Processing Time in TI eZdsp F2812

inHi I have a question regarding the flow of my code. I am oversampling my input signal using the ADC at a rate 3.125 MHz. I have 2 inputs & am...

Hi I have a question regarding the flow of my code. I am oversampling my input signal using the ADC at a rate 3.125 MHz. I have 2 inputs & am using simultaneous sampling. I am using the adcseqovdtest code of TI as a framework. So I have 16 samples from the ADC Result registers. My question is with sampling rate of 3.125 and clock frequency of 150 MHz, I have (150/3.125) 48 instructions per samp...

## Oversampling and quantization...

inHopefully some of you can point me to the solution of this problem. If I oversample a signal, I quantize it and then I reduce the sampling...

Hopefully some of you can point me to the solution of this problem. If I oversample a signal, I quantize it and then I reduce the sampling rate with a decimator by a factor M, I can improve the QSNR by a factor of log2(M). Nice and easy. But what if I lower the sampling rate using a fitting technique? I mean if I know how the signal is done and I retrieve some parameters out of it using a f...

## Oversampling technique need help...

inHello all, I have IR preamp with a gain of 64dB, the output noise is about 50mV peak to peak for a signal of 4V peak peak (max) and the bandwidth...

Hello all, I have IR preamp with a gain of 64dB, the output noise is about 50mV peak to peak for a signal of 4V peak peak (max) and the bandwidth is 350kHz. I have a AD7626 (16 bits 10MSPS ADC) which is largly suffisient for my aplpication. I would want to know what would be the best method to filter the noise (which is white noise and 1/f noise which come from the IR detector) in my band of i...

## Oversampling 8KHz to 44.1KHz

inThere's a 8KHz audio sample rate I want to convert up to 44.1KHz sample rate. What's the right approach to keep Mr. Nyquist happy?

There's a 8KHz audio sample rate I want to convert up to 44.1KHz sample rate. What's the right approach to keep Mr. Nyquist happy?

## Calculate variance of noise

inHI All I really need your help to understand this noise concept. Can you please tell me how to calculate noise variance for...

HI All I really need your help to understand this noise concept. Can you please tell me how to calculate noise variance for bandpass simulation? And does oversampling affects noise variance calculation. Your help will be greatly appreciated. Thanks Chintan

## Timing recovery by oversampling in QAM systems

inHi, A basic question about QAM. I've noticed that there are timing recovery systems that calculate the 'correct' sample by means of an...

Hi, A basic question about QAM. I've noticed that there are timing recovery systems that calculate the 'correct' sample by means of an interpolation guessing wich one of this intermediate samples is the most suitable instead of closing a loop and recovering and using the recovered clock as a receiver clock.. It seems to me quite interesting but I have a doubt: If we don't synchronize the...

## oversampling from 8khz to 44.1khz using multistage filter

inhello all, I want to design a sample rate converter to convert the sampling rate from 8khz to 44.1khz. What should be the designing steps? What...

hello all, I want to design a sample rate converter to convert the sampling rate from 8khz to 44.1khz. What should be the designing steps? What about multistage fiter design.Please help me out!!! regards, pragati

## Oversampling and receiver

inHi all, I would like to know if the folling would be possible. Lets say that my tx use a raised cosine filter to limit the bandwidth of my...

Hi all, I would like to know if the folling would be possible. Lets say that my tx use a raised cosine filter to limit the bandwidth of my transmitted signal. At the receiver I would oversample the received signal by a factor of x and by using a Viterbi algorithm I would be able to approximate every symbol affected by ISI caused by the memory of my raised cosine filter. By doing this would i...

## Oversampling using Cheby2 IIR FIlter.

inI have to use a cheby2 IIR filter with 60db bandstop ripple to implement oversamplig procedure. I'm sure that I can calculate the coefficient...

I have to use a cheby2 IIR filter with 60db bandstop ripple to implement oversamplig procedure. I'm sure that I can calculate the coefficient with matlab in few minutes, but in my application I have to calcute it in real time depending on the cut-off frequency. My question is: thers is an analitic rappresentation of the transfer function of cheby2 filter dapending on the frequency in lapl...

## Query on AIC-23 Codec

inHi All, i am going through the datasheet of AIC-23 Codec on TI board, in the datasheet i have come acrros this statement BOSR...

Hi All, i am going through the datasheet of AIC-23 Codec on TI board, in the datasheet i have come acrros this statement BOSR Base oversampling rate USB mode: 0 = 250 fs 1 = 272 fs Normal mode: 0 = 256 fs 1 = 384 fs where 0 and 1 are the bit to be set in the BOSR Register. My Query is, what actually mean by t...

## Tx and Rx filters gains and energies

inHi All, Although it is a basic question but I couldn't find its answer in any available reference. When we filter the signal at the Tx and Rx,...

Hi All, Although it is a basic question but I couldn't find its answer in any available reference. When we filter the signal at the Tx and Rx, how should we adjust the filter gains or filter energies to keep the overall energy figures correct *at every stage*. For example, should Tx filter gain be necessarily set to the oversampling factor, or what should be the Rx filter gain. Thanks. _...

## Carrier Recovery for QPSK

inHi everyone, As a part of problem, I have to implement carrier recovery in some distributed MISO communication system. I was following one...

Hi everyone, As a part of problem, I have to implement carrier recovery in some distributed MISO communication system. I was following one paper to implement that problem which targeted to estimate the f offset in the range of (1 / (2Ts) ) ( for Ts is the oversampling time ). The f offset is estimated with minute error about which author suggested the use of PLL to handle it, but didn't r...

## physical layer A/D performance simulation

inHi, I want to simulate the physical layer for CDMA IS-95, i've wrote the bs_signal and the channel model, the rrc filter in the BS site(tx)...

Hi, I want to simulate the physical layer for CDMA IS-95, i've wrote the bs_signal and the channel model, the rrc filter in the BS site(tx) use 8x oversampling with baseband model. The question is how to simulate the receiver-side's frequency error induced during downconverter and the A/D timing issue during A/D? also the digital AGC performance? B.R. Thanks.

## Adding noise to ADC input to increase accuracy

inDear all, I have just been reading about the use of oversampling in a decimator to enhance the resolution of a sampled signal. The idea is...

Dear all, I have just been reading about the use of oversampling in a decimator to enhance the resolution of a sampled signal. The idea is to sample a signal containing 0.5LSB white noise at samplerate of N times the Nyquist rate. It is then possible to extract log4(N) extra bits of resolution by summing N samples. However there is another scheme which can provide much more of an increase...

## symbol synchronization method for SDR in Matlab?

inhello, any of you has experience with different methods for symbol synchronization so you can help me to implement one of them in a receiver for...

hello, any of you has experience with different methods for symbol synchronization so you can help me to implement one of them in a receiver for bpsk modulation? i've implemented a costas loop for carrier recovery and the code i've found for symbol synchronization is too heavy and takes too much time. this is the matlab code: tnow=del*oversampling+1; tau=0; xs=zeros(1,length(y)); % i...

## High pass polyphase filter

inHi all, I'm trying to design an high pass polyphase filter. The approach is to take the 5 tap high pass FIR, oversample it by a factor N...

Hi all, I'm trying to design an high pass polyphase filter. The approach is to take the 5 tap high pass FIR, oversample it by a factor N (usually 128 or 256), then subsample it again into the different phases. The oversampling was done by polynomial interpolation and by zero-padding and low-pass. I mean, the two methods were tried, not altogether. In both cases, the results are dis...

## Increase resolution through decimation

inHi I need to take a standard 8bit ADC which samples at 40Msps increase the resolution by about 4 or 5 bits. I know that oversampling spreads...

Hi I need to take a standard 8bit ADC which samples at 40Msps increase the resolution by about 4 or 5 bits. I know that oversampling spreads the quantization noise over a wider bandwidth thereby decreasing the SQNR. So i can increase the resolution through decimation? How do I increase the resolution through decimation? It decimates the signal frequency but i don't physically know how to increa...

## Design of anti-alias filter for ADC, with oversampling and averaging

inHi, I am trying to design proper anti-aliasing filters for a new hobby project (digital control of a quad-rotor flying robot - see...

Hi, I am trying to design proper anti-aliasing filters for a new hobby project (digital control of a quad-rotor flying robot - see previous post for more questions). Here are the specifics: * My sensors are analog MEMS accelerometers and gyroscopes. I'll have at least 6 sensors to process, at least initially. * I will be using a microcontroller with 10-12 bit built-in ADCs to process t...

## ADC Vs DAC

inHi all, I am not very familiar with ADC or DAC design or present research in these area. Popular sigma-delta,Flash or successive appoximation...

Hi all, I am not very familiar with ADC or DAC design or present research in these area. Popular sigma-delta,Flash or successive appoximation ADC design methods are matured(?). I guess same terminology(sigma delta etc.) holds good for DAC. Desiner cum researcher talk about high resolution(dynamic range), high speed DAC and ADC using oversampling techniques over low resolution ADC/DAC....

## CAUTION! was "What is the advantage on high-sampling rate ?"

inHi Guys, in a recent thread, mention was made of a "Sampling" paper by Dan Lavry. At the following web...

Hi Guys, in a recent thread, mention was made of a "Sampling" paper by Dan Lavry. At the following web site http://www.lavryengineering.com/pdfs/sample.pdf you can see Dan's 1997 paper: "Sampling, Oversampling, Imaging and Aliasing - a basic tutorial". I recommend caution if you decide to read that paper. In the second paragraph Dan wrote: *** Sampling theory *** ...