## Intro to Goertzel for math challenged antique

Started by in comp.dsp16 years ago 5 replies

I saw a post somewhere that mentioned Goertzel in passing. It gave enough info to realize that someone had already invented "wheel"...

I saw a post somewhere that mentioned Goertzel in passing. It gave enough info to realize that someone had already invented "wheel" ;} Consulting Lyons 13.17 (second edition) confirmed that it may be what I'm looking for. He gives a response plot with "m" as independent variable. To confuse me further, figures 13-43(b) seems at odds with 13-45. I suspect they are plotting different thi...

## What is "bandwidth" of Goertzel algorithm?

Started by in comp.dsp14 years ago 8 replies

Looking at Wikipedia article on Goertzel algorithm I thought I might be able to use it as a quick and dirty filter. I'm interested in looking...

Looking at Wikipedia article on Goertzel algorithm I thought I might be able to use it as a quick and dirty filter. I'm interested in looking at formants. Looking at the spectra of my specific test case, I'd want something from 10% of center to 1/3 octave but being> = 20db down an octave away.

## Am I reinventing Goertzel etc?

Started by in comp.dsp14 years ago 13 replies

pseudo code in Scilab notation time=[start_time:(1/sample_rate):(start_time+N/sample_rate)]; signal =...

pseudo code in Scilab notation time=[start_time:(1/sample_rate):(start_time+N/sample_rate)]; signal = S[1:N]; analysis_real=sin(2*%pi*time); analysis_imag=cos(2*%pi*time); output=((signal*analysis_real')^2 +(signal*analysis_imag')^2)^.5 Is that Goertzel? or Could someone point me to source code for Goertzel in BASIC or FORTRAN? I've found C/C++ source but I don't read C.

## Goertzel algorithm:Overflow occured in Call Progress Detection!

Started by in comp.dsp16 years ago 1 reply

Dear friends I need to implement a call progress tone detector using goertzel algorithm. To avoid strong signal inputs to the Goertzel...

Dear friends I need to implement a call progress tone detector using goertzel algorithm. To avoid strong signal inputs to the Goertzel filters, additional gain control is used to prevent early overflow: ; Control gain of the input sample x(n) ; On a 32 samples length buffer of input samples, the average peak ; amplitude GAIN_amp is computed using the last 32 samples. The current ; input...

## Goertzel algorithm doubth......

Started by in comp.dsp18 years ago 1 reply

Hi, I don?t know how to interpretate the output of the Goertzel algorithm. It is either y(N)=X(k) or y(N-1)=X(k), but I don't know what the...

Hi, I don?t know how to interpretate the output of the Goertzel algorithm. It is either y(N)=X(k) or y(N-1)=X(k), but I don't know what the correct is. Thanks a lot.

## GOERTZEL ALGORITHM VERIFICATION

Started by in comp.dsp13 years ago 3 replies

Hi all, I want to implement Goertzel algorithm for DTMF detection, I want to know the basic things to consider to implement it i.e should...

Hi all, I want to implement Goertzel algorithm for DTMF detection, I want to know the basic things to consider to implement it i.e should i directily Choose N(sample length)=205 (as more optimsed) or which factors should be taken in acccount for it. Also how should i test my code i.e what inputs should i use for simulation? is there any standard I/O files available? Tha...

## Goertzel Frequency Resolution

Started by in comp.dsp16 years ago 4 replies

Hi, Could someone give me the formula to calculate the frequency resolution for a Goertzel filter? I saw somewhere that it was fs/N, where fs...

Hi, Could someone give me the formula to calculate the frequency resolution for a Goertzel filter? I saw somewhere that it was fs/N, where fs is the sampling frequency and N is the block size, is this correct?

## The slippery slope of sliding Goertzels

Started by in comp.dsp16 years ago 3 replies

Nearly 30 years after first reading about the sliding-window Goertzel algorithm, I finally have cause to try implementing it. :-) My...

Nearly 30 years after first reading about the sliding-window Goertzel algorithm, I finally have cause to try implementing it. :-) My understanding is you just add one step to the recursive part of the usual Goertzel algorithm - you just subtract the input sample from one block length back. I tried that, and it basically works. However, there are various grubby little details which bothe...

## DTMF ENERGY LEVELS

Started by in comp.dsp13 years ago 6 replies

Hi all, I am new to Goertzel algorithm so having some basic doubts about its implementation. As per thr standatd Q.24 (AT&T) Power levels per...

Hi all, I am new to Goertzel algorithm so having some basic doubts about its implementation. As per thr standatd Q.24 (AT&T) Power levels per frequency = 0 to -25 dBm; what does this actually means? also what is minimum threshold level for any digit? I have a code for goertzel algorithm form wikipedia where r[]= array containing magnitude for respective bin frequencies col= colu...

## Another Goertzel question

Started by in comp.dsp18 years ago 39 replies

Hi Guys, our DSP pal Jon Harris and I have exchanged a few E-mails regarding the Goertzel algorithm. If you recall, the Geortzel...

Hi Guys, our DSP pal Jon Harris and I have exchanged a few E-mails regarding the Goertzel algorithm. If you recall, the Geortzel algorithm is implemented with an IIR filter structure with a 2cos(2*pi*k/N) feedback coefficient and an -exp(-j2*pi*k/N) feedforward coefficient. The value k, which defines the frequency at which the filter resonates, is typically specified to be a...

## Goertzel detector to Goertzel filter?

Started by in comp.dsp18 years ago 7 replies

I have looked at an article by Kevin Banks which specifies the following use of the Goerzel Algorithm for tone detection: It shows the following...

I have looked at an article by Kevin Banks which specifies the following use of the Goerzel Algorithm for tone detection: It shows the following recursive technique where the detection decision is made after N samples: -------------article-------------------------------- Defining: w = (2*?/N)*k cosine = cos w sine = sin w coeff = 2 * cosine For the per-sample processing you're ...

## Goertzel algorithm

Started by in comp.dsp8 years ago 4 replies

Hello. I'm new to DSP programming and I need your help. I'm implementing the Goertzel algorithm for detection of DTMF codes and I'm having...

Hello. I'm new to DSP programming and I need your help. I'm implementing the Goertzel algorithm for detection of DTMF codes and I'm having trouble with interpreting the results. I created a sample signal and tested the whole frequency range for a peek. A peek was found at the desired frequency but the value of the result is very strange. It doesn't resemble in any way the original amplitude of...

## BPSK decode with Goertzel Algorithm

Started by in comp.dsp17 years ago 19 replies

Hi folks, I am about to attempt to decode a very weak RF BPSK signal using a sliding Geortzel Algorithm. I need to do this for the purpose of...

Hi folks, I am about to attempt to decode a very weak RF BPSK signal using a sliding Geortzel Algorithm. I need to do this for the purpose of speed and sensitivity. Has anyone ever tried this before? It should be possible seeing that you can recover both the real and imaginary portions of the signal using the Goertzel. I have a nice chunk of C code to do this but have only used the optimiz...

## Sliding Goertzel problem

Started by in comp.dsp8 years ago 16 replies

Hello somebody, does somebody have experiences with sliding Goertzel algorithm? With K, which is not integer number? And what about some...

Hello somebody, does somebody have experiences with sliding Goertzel algorithm? With K, which is not integer number? And what about some differences between G. filter and G. algorithm? Last week I implemented GA in DSP (Freescale 56F8037) and it works very well for integer K, but for non-integer K this alorithm gives incorrect results. If I tried to use "normal" GA (without sliding), it beg...

## Newbie Q: Goertzel threshold testing, speech detection

Started by in comp.dsp17 years ago 2 replies

Hi, I'm currently using the Goertzel algorithm to do DTMF detection. Currently, I get the magnitude for each DTMF frequency, save the...

Hi, I'm currently using the Goertzel algorithm to do DTMF detection. Currently, I get the magnitude for each DTMF frequency, save the sums of the magnitudes that correspond to each number, then I assume whichever sum is the highest must the be the most likely DTMF key. This works, but seems kludgy. I do it this way because I'm having a hard time determining an appropriate threshold val...

## Coupled form Goertzel

Started by in comp.dsp8 years ago 6 replies

Hello, recently I have read very interesting article about Coupled-form 2nd-order IIR resonators which was written by Rick Lyons. The...

Hello, recently I have read very interesting article about Coupled-form 2nd-order IIR resonators which was written by Rick Lyons. The princip of this form of resonator is clear for me, but I have got still some problems if I try to associate it with Goertzel algorithm. I have created short simulation script in Matlab, but I cannot find the mistake. Output is terrible, there are a lot of swi...

## Goertzel to recognize DTMF in Java

Started by in comp.dsp17 years ago 5 replies

Hello, Im working on the recognition, from a wav file, of DTMF tones. The program is being done in Java. What i do is open the file, get the...

Hello, Im working on the recognition, from a wav file, of DTMF tones. The program is being done in Java. What i do is open the file, get the info in a byte array and pass it to a double array. Now im not sure what to do. Ive heard that the best algorithm for this task is Goertzel, but I havent been able to find information that works for me. Has anybody tried this before, does it work? ...

## DTMF detection and samples

Started by in comp.dsp16 years ago 2 replies

Hi. I?m a newbie in this but I need to acomplish a job with this stuff. I?m capturing sound through the sound blaster and then need to detect if...

Hi. I?m a newbie in this but I need to acomplish a job with this stuff. I?m capturing sound through the sound blaster and then need to detect if there were some DTMF. For this I?m using Goertzel. What I can?t understand is about buffering and samples, I mean: Do I have to run the goertzel for N=106 on each sample and sum all the results and then try to detect if there were DTMF or this is processi...

## Finding phase and mag at particular freq

Started by in comp.dsp14 years ago 7 replies

Hi I got two quadrature input streams, I and Q. I need to find phase and magnitude at a particular frequency for both of them and then...

Hi I got two quadrature input streams, I and Q. I need to find phase and magnitude at a particular frequency for both of them and then compare these values. Is goertzel the fastest way to do it. Also, is goertzel algorithm valid if the frequency is not a multiple of fs/N. where fs = sampling frequency N = no of samples. Do i have to use cos(2.pi.k/N) or can i also use cos(2.pi.freq/fs)( where...

## FIR Filter

Started by in comp.dsp17 years ago 22 replies

Hi, As i've got problems using FFT or Goertzel algorithm (for those who are interested by the reason see my previous post called...

Hi, As i've got problems using FFT or Goertzel algorithm (for those who are interested by the reason see my previous post called "some goertzel questions"), i'll try to use a narrow bandpass filter. I already made one some months ago. It was a FIR filter with a bandpass 300-1000 Hz and a sample frequency of 8000 Hz. Now i'd like to design a narrower filter centered on 9 kHz with a highe...