en:wiki:funktionen:td-functions:phase_extraction
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en:wiki:funktionen:td-functions:phase_extraction [29/06/2016 13:47] – uli | en:wiki:funktionen:td-functions:phase_extraction [30/06/2016 18:22] (current) – hamish | ||
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**Options: ** | **Options: ** | ||
- | * //Minimum phase: //Es wird die Minimalphase berechnet. Diese beschreibt diejenige Pulsantwort, die den gegebenen Frequenzgang mit den minimalsten Phasenänderungen erzielt. Die Pulsantwort hat den kleinsten Zeitbedarf und die kleinste Verzögerung | + | * //Minimum phase: //This option is used to calculate the unique impulse which has the specifed frequency response and is Minimum Phase. A minimum phase filter has the smallest possible group delay at any given frequency (consistent with producing the required overall frequency response), and hence the smallest signal latency, but the group delay may not be constant at all relevant frequencies. The minimum phase impulse has no pre-ringing but may have post-ringing. The location of the pulse peak is usually at or near the first sample of the filter. |
- | * //Linear phase: //Es wird die Linearphase berechnet. Diese beschreibt eine Pulsantwort, die einen gegebenen Frequenzgang ohne Phasenänderungen erzielt. Charakteristisch hierfür ist die Symmetrie der Pulsantwort, die Pulsspitze befindet sich in der Pulsmitte. Demzufolge weist die Pulsantwort eine Verzögerung = halbe Pulslänge | + | * //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 |
- | * //Excess phase: //Hierbei wird aus einer Pulsantwort mit gemischter Phase die Exzessphase berechnet. Das Resultat ergibt eine Pulsantwort, | + | * //Excess phase: //This option calculates a filter with constant |
- | * //Advanced mixed phase: //mit dieser Option kann unter Beibehaltung des Frequenzgangs ein beliebiger Phasenverlauf zwischen Minimalphase | + | * //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, |
- | \\ **Use:** \\ Ein Korrekturfilter für eine gemischtphasige Pulsantwort bedingt prinzipiell eine Verzögerung. Bei reiner Audiowiedergabe spielt diese zumeist keine Rolle. Im Fall von Video bzw. bei Live-Musik ist die Verzögerung aber möglicherweise nicht akzeptabel. Hier wird mit einem minimalphasigen Korrekturfilter die kürzeste Durchlaufzeit erreicht. Dafür wird aber keine Exzessphase korrigiert. | + | \\ **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. |
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 [[: | 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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- | 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.1467208056.txt.gz · Last modified: 29/06/2016 13:47 by uli