## Forums comp.dsp

## Plet's Second Estimator

inHi Group This is a new estimator based on real and imaginary values of two DFT bins. The estimator is exact for a pure sinusoid without...

Hi Group This is a new estimator based on real and imaginary values of two DFT bins. The estimator is exact for a pure sinusoid without noise. It performs well in the presence of noise. Let k be the index of the DFT bin with the largest magnitude. Let j be the index of the DFT bin with the largest magnitude neigboring bin k. That is j=k-1 or j=k+1. Now let Sk = Sin(2*PI*k/N) Ck ...

## Searching for fixed point g.728 sources

inI am searching for a Fixed Point C implementation of G.728 codec. Can anyone point me to it's free version or sell it to me? Thanks.

I am searching for a Fixed Point C implementation of G.728 codec. Can anyone point me to it's free version or sell it to me? Thanks.

## New frequency estimator from two DFT bins

inHi Group I have derived this estimator. The limited tests I have done shows high accuracy. Let k be the index of the DFT bin with the...

Hi Group I have derived this estimator. The limited tests I have done shows high accuracy. Let k be the index of the DFT bin with the largest magnitude. Let j be the index of the DFT bin with the largest magnitude neigboring bin k. That is j=k-1 or j=k+1. Now let P=Tan(PI*k/N) and Q=Tan(PI*j/N) Then the normalized frequency is estimated by: Freq=(N/PI)*Arctan(Sqr(P*Q*(Im[k]*P...

## Zero-Order Hold in control ystems

inWhen you have digital control with feedback we take account of the ZOH in t= he DAC. This is in all the textbooks and shows a pulse as the...

When you have digital control with feedback we take account of the ZOH in t= he DAC. This is in all the textbooks and shows a pulse as the impulse respo= nse and you get the sinc for the magnitude of it and a linear phase charact= eristic. You then need to sample about 10 times the max freq of interest so= as not to get too much phase lag from this. However, many systems nowadays have H br...

## Wavelets? Dufuslets?

inGiven a complex-valued signal, extending from some negative frequency to some positive frequency. Is there some way to separate that signal...

Given a complex-valued signal, extending from some negative frequency to some positive frequency. Is there some way to separate that signal into a bunch of overlapping channels, regularly spaced, other than to have a bunch of filters all running in parallel? I'm thinking there has to be something clever involving FFTs, but I keep utterly failing to figure it out. To make it more c...

## All-real FFT for FPGA

inSo, there are algorithms out there to perform an FFT on real data, that save (I think) roughly 2x the calculations of FFTs for complex...

So, there are algorithms out there to perform an FFT on real data, that save (I think) roughly 2x the calculations of FFTs for complex data. I did a quick search, but didn't find any that are made specifically for FPGAs. Was my search too quick, or are there no IP sources to do this? It would seem like a slam-dunk for Xilinx and Intel/Altera to include these algorithms in their FFT li...

## CORDIC

inI don't think I've ever really dug into the CORDIC algorithm enough to appreciate the logic involved. I do recall coming to the realization...

I don't think I've ever really dug into the CORDIC algorithm enough to appreciate the logic involved. I do recall coming to the realization that the shift and add/subtract algorithm is not overly different from a multiplication, so I had trouble understanding why touted as a way to avoid the use of a multiplier. Looking at it harder, it would appear that the level of complexity is th...

## DDS LUT Size Calculation

inI just wrote a program to calculate the size of the LUT required to generate the coarse sin/cos values (a in the following equation) to use...

I just wrote a program to calculate the size of the LUT required to generate the coarse sin/cos values (a in the following equation) to use the trig identity sin(a+b) = sin(a)cos(b) + cos(a)sin(b), meaning the max value of b is sufficiently small that cos(b) is 1.0 to within one lsb of the output sine word. The size of a and b (meaning the number of bits) always turns out to be half o...

## Mother or base wavelet by fitting

Has anyone done nonlin regression of Resnikoff parameters on basic wavelets - = - Vasos Panagiotopoulos, Columbia'81+, Reagan,...

Has anyone done nonlin regression of Resnikoff parameters on basic wavelets - = - Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist http://www.panix.com/~vjp2/vasos.htm ---{Nothing herein constitutes advice. Everything fully disclaimed.}--- [Homeland Security means private firearms not lazy obstructive guards] [Urb sprawl confounds terror] [...

## "Pick you Wavelet" by Guo

Is that Java applet around any more? It had sliding pots for picking resnikoff parameters - = - Vasos Panagiotopoulos,...

Is that Java applet around any more? It had sliding pots for picking resnikoff parameters - = - Vasos Panagiotopoulos, Columbia'81+, Reagan, Mozart, Pindus, BioStrategist http://www.panix.com/~vjp2/vasos.htm ---{Nothing herein constitutes advice. Everything fully disclaimed.}--- [Homeland Security means private firearms not lazy obstructive guards] [Urb spraw...

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