en:wiki:funktionen:td-functions:phase_extraction
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en:wiki:funktionen:td-functions:phase_extraction [29/06/2016 13:44] – uli | en:wiki:funktionen:td-functions:phase_extraction [30/06/2016 18:22] (current) – hamish | ||
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**Options: ** | **Options: ** | ||
- | * | + | |
+ | * //Linear phase: //This option is used to calculate a filter (impulse) which has the specified frequency response with a constant group delay at all frequencies. The price for a constant group delay is that the absolute group delay is large. The large constant delay may not matter if listening to audio, but needs to be taken into account if audio is live or needs to be synchronized with video. The impulse is symmetric, with the pulse peak located in the center of the filter. Accordingly, | ||
+ | * //Excess phase: //This option calculates a filter with constant 0 dB frequency response but which incorporates any group delay in the input curve in excess of that which the minimum phase component of that curve would produce. Because of the flat amplitude response, such a filter is often called an "All Pass" filter. A typical impulse response can be separated into the minimum phase component and the excess phase component. Convolving the two components reproduces the original pulse. | ||
+ | * //Advanced mixed phase: //With this option, while maintaining the frequency response, any phase curve between minimum phase (0), Linear Phase (1) and maximum phase (2) are calculated. The parameter can also be in between, for example, 0.159. Possible application: | ||
+ | \\ **Use:** \\ The choice of correction filter for a mixed-pulse response may be due principally to the amount of acceptabe delay. For pure audio reproduction this usually does not matter. In the case of video or live music, a large delay may not be acceptable. Here the shortest lead time is achieved with a minimum phase correction filter. But no excess phase is corrected. | ||
- | //Minimum phase: //Es wird die Minimalphase berechnet. Diese beschreibt diejenige Pulsantwort, | + | A limited band of frequency response can be used for a correction with this function with the frequency response information discarded above or below the selected spectrum (that is, the frequency response output of this funtion is a horizontal straight line below the lower limit and above the higher limit). This function is required, for example to use a near-field recording of frequency response of a speaker driver [[: |
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- | + | ||
- | //Linear phase: //Es wird die Linearphase berechnet. Diese beschreibt eine Pulsantwort, | + | |
- | * | + | |
- | + | ||
- | //Excess phase: //Hierbei wird aus einer Pulsantwort mit gemischter Phase die Exzessphase berechnet. Das Resultat ergibt eine Pulsantwort, | + | |
- | * | + | |
- | + | ||
- | //Advanced mixed phase: //mit dieser Option kann unter Beibehaltung des Frequenzgangs ein beliebiger Phasenverlauf zwischen Minimalphase (0), Linearphase (1) und Maximalphase (2) berechnet werden. Der Parameter kann auch dazwischen liegen, also z.B. 0.159. Anwendungsmöglichkeit: | + | |
- | \\ **Use:** \\ A limited band of frequency response can be used for a correction with this function with the frequency response information discarded above or below the selected spectrum (that is, the frequency response output of this funtion is a horizontal straight line below the lower limit and above the higher limit). This function is required, for example to use a near-field recording of frequency response of a speaker driver [[: | + | |
\\ **Example: | \\ **Example: | ||
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- | In this case it is important that the uncorrected range of frequencies above approximately 150hz have the same gain applied by the filter, otherwise it will affect the balance of the channels. So for the next step there are two possibilities: | + | In this case it is important that the uncorrected range of frequencies above approximately 150hz have the same gain applied by the filter, otherwise it will affect the balance of the channels. So for the next step there are two possibilities: |
- | Now activate the curve 1 on the radio button and select TD Functions> | + | Now activate the curve 1 on the radio button and select TD Functions> |
en/wiki/funktionen/td-functions/phase_extraction.1467207891.txt.gz · Last modified: 29/06/2016 13:44 by uli