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# Coherent Fft

11 Threads found on edaboard.com: Coherent Fft

Which windowing function are you using? Also can you double check if your coherent sampling is correct.

Hello guys, I have implemented an ideal ADC+DAC converter and I did an fft analysis. I did a test with coherent sampling with rectangular window and everything was ok. Input freq. 1,376...MHz, 500mV, sinewave and a starting phase of -90?. That gave Me 7,96bits (8bits ideal). Then I changed the phase to -60? and rectangular window and gave me

## SNDR measurement issues

I'm trying to measure the SNDR of a SHA, but I'm having issues with my measurement setup. The sampling clock is 5MHz, and the input frequency is 2.0068359375 MHz, fft length 1024 for coherent sampling (411 cycles). I am using output strobing to ensure there's no interpolation when the fft samples. I'm trying to make sure my (...)

## Coherent Integration in VHDL

I'm getting the raw captured data from a RT signal acquisition card. I have to perform time domain averaging so (imho) there is no question of Ifft. Provision of storage is there (FIFO, RAMs) but how can I go about the algorithm? Need to perform coherent integration (pulse integration) for N pulses to improve SNR by N times.

## FFT window, Quantization and Noise Floor

If you do not use "coherent sampling" you need to apply a window function to your signal before the fft, see below.nsignal=4096; fs=44100; f=1001*fs/nsignal; % coherent sampling i.e. integer number of cycles (1001) in nsignal samples %f=1000; %non-coherent sampling. Use hann window below t=/fs; y=1*sin(2*pi*f*t); w=ones(nsignal,

## hy we need t coherent sampling to calculate SNR in N-ADC's

Unless you use an adequate windowing function for sampling then coherent sampling is needed to increase your fft spectral resolution. Without windowing or coherent sampling you'll have waveform discontinuancies and see spectral leakage / artifacts in your fft data i.e You see spreading of energy for one frequency across (...)

## need help regarding coherent demodulation in matlab

hi i want to do coherent demodulation in matlab using fft at each step can anybody plz help me with that?

## A Question About Calculating FFT in Delta Sigma Modulators

Remember that the output of a Delta-Sigma is typically not periodic, even if your input is. As a consequence, you won't be able to use coherent sampling (sample an integer number of cycles). When you generate your fft, this will produce spectral leakage -- part of your signal will "spill over" into adjacent frequency bins. So by using the signal bi

## PN code noncoherent acquisition frequency offset problem

If I understand ur problem correctly .. U r trying to Acquire a PN code having some doppler (frequency offset) from base band. The best approach I can think is fft acquisition technique if u r using DSP processor for acquisition . U take coherent data and then do non coherent integration for reducing noise, finally perform (...)

## question of sigma delta simulation

what is the resolution in ur design? if the resolution is small then how much is the quantization noise level? if big then how about the thermal noise in the sc? how about the dc gain of ur opamp? if everything ok, then you have to increase the # of points in fft and meantime you have to use coherent sampling,that is u have to make sure fin/fsamp

## How to calculate SNR in this case?

Hi all, I am design a 10bits pipeline ADC and by followingprevious articles I use Matlab to do fft. But here are the problems I met. fin=100Khz, fs=10Mhz, N=8192(number of data points in fft), M=83 (integer number of cycles within the sampling window), First I used coherent sampling method to do fft and I got a (...)

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