User Guide/Spectrogram and Parameter Viewer/Methods/F0 (harmonic grid) method: Difference between revisions
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This method uses a harmonic grid algorithm to detect the fundamental frequency of a harmonic tone (or a mixture of tones) in the FFT amplitude spectrum. A simple tracking algorithm is applied to the resulting values of consecutive frames. The result is the parameter function <code>F0H</code>(t) which can be stored in the DataSet. | This method uses a harmonic grid algorithm to detect the fundamental frequency of a harmonic tone (or a mixture of tones) in the FFT amplitude spectrum. A simple tracking algorithm is applied to the resulting values of consecutive frames. The result is the parameter function <code>F0H</code>(t) which can be stored in the DataSet. | ||
[[File:v2_method_f0_harmonic_grid_linear.png]] | [[File:v2_method_f0_harmonic_grid_linear.png]] | ||
min/max | ;min/max | ||
:Define the analysis and display fundamental frequency range in Hz. | |||
Define the analysis and display fundamental frequency range in Hz. | ;ref | ||
:This is the reference frequency for Cent conversions. | |||
ref | ;Hz | ||
:Select the frequency unit for the display. | |||
This is the reference frequency for Cent conversions. | ;f1, f2 | ||
:Define the frequency search component search range in Hz. This range can be outside the fundamental frequency range defined above. | |||
Hz | ;harmonics | ||
:This is the minimum number of harmonic components building a harmonic tone. The value must be greater than or equal to <code>1</code>. | |||
Select the frequency unit for the display. | ;threshold | ||
:Selects how the amplitude threshold for the component detection algorithm is computed. When a linear function threshold is specified, a linear function between the points (f1,a1) and (f2,a2) is computed and only peaks with amplitudes above this line are detected. For the threshold type cepstrum-smoothed spectrum, only peaks with amplitudes above the smoothed spectrum + offset are detected. The smoothed spectrum is an adaptive threshold and is very efficient for signals with a high dynamic range. | |||
f1, f2 | ;a1,a2 | ||
:The threshold amplitudes for the threshold type linear function. | |||
Define the frequency search component search range in Hz. This range can be outside the fundamental frequency range defined above. | ;rel. to spg-maximum | ||
:The amplitude values are calculated relative to the spectrogram's maximum amplitude. | |||
harmonics | ;coefs | ||
:Number of coefficients for cepstrum smoothing. | |||
This is the minimum number of harmonic components building a harmonic tone. The value must be greater than or equal to <code>1</code>. | ;offset | ||
:Amplitude offset for peak detection if the threshold is set to cepstrum-smoothed spectrum. | |||
threshold | |||
Selects how the amplitude threshold for the component detection algorithm is computed. When a linear function threshold is specified, a linear function between the points (f1,a1) and (f2,a2) is computed and only peaks with amplitudes above this line are detected. For the threshold type cepstrum-smoothed spectrum, only peaks with amplitudes above the smoothed spectrum + offset are detected. The smoothed spectrum is an adaptive threshold and is very efficient for signals with a high dynamic range. | |||
a1,a2 | |||
The threshold amplitudes for the threshold type linear function. | |||
rel. to spg-maximum | |||
The amplitude values are calculated relative to the spectrogram's maximum amplitude. | |||
coefs | |||
Number of coefficients for cepstrum smoothing. | |||
offset | |||
Amplitude offset for peak detection if the threshold is set to cepstrum-smoothed spectrum. |
Latest revision as of 15:33, 28 August 2015
This method uses a harmonic grid algorithm to detect the fundamental frequency of a harmonic tone (or a mixture of tones) in the FFT amplitude spectrum. A simple tracking algorithm is applied to the resulting values of consecutive frames. The result is the parameter function F0H
(t) which can be stored in the DataSet.
- min/max
- Define the analysis and display fundamental frequency range in Hz.
- ref
- This is the reference frequency for Cent conversions.
- Hz
- Select the frequency unit for the display.
- f1, f2
- Define the frequency search component search range in Hz. This range can be outside the fundamental frequency range defined above.
- harmonics
- This is the minimum number of harmonic components building a harmonic tone. The value must be greater than or equal to
1
. - threshold
- Selects how the amplitude threshold for the component detection algorithm is computed. When a linear function threshold is specified, a linear function between the points (f1,a1) and (f2,a2) is computed and only peaks with amplitudes above this line are detected. For the threshold type cepstrum-smoothed spectrum, only peaks with amplitudes above the smoothed spectrum + offset are detected. The smoothed spectrum is an adaptive threshold and is very efficient for signals with a high dynamic range.
- a1,a2
- The threshold amplitudes for the threshold type linear function.
- rel. to spg-maximum
- The amplitude values are calculated relative to the spectrogram's maximum amplitude.
- coefs
- Number of coefficients for cepstrum smoothing.
- offset
- Amplitude offset for peak detection if the threshold is set to cepstrum-smoothed spectrum.