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Algorithms - The Goertzel Algorithm

 

SigLib Library

 

Digital Filter Plus

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Many applications require the detection of a few discrete sinusoids. The Goertzel filter is an IIR filter that uses the feedback to generate a very high Q bandpass filter where the coefficients are easily generated from the required centre frequency, according to the following equations. The most common configuration for using this technique is to measure the signal energy before and after the filter and to compare the two. If the energies are similar then the input signal is centred in the pass-band, if the output energy is significantly lower than the input energy then the signal is outside the pass band. The Goertzel algorithm is most commonly implemented as a second order recursive IIR filter, as shown below.


These algorithms are included for information and are by no means definitive descriptions. If you would like to add anything to these pages then please feel free to email me and I will add your information, with my thanks.


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