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--- en:wiki:funktionen:td-functions:reversion [24/06/2016 15:37] – uli
+++ en:wiki:funktionen:td-functions:reversion [02/01/2021 17:42] (current) – hamish
@@ Line 1: / Line 1: @@
+====== Reversion ======
+<font 14px/Arial, sans-serif;;initial;;#ffffff>**Description:**</font>
-**This page is not fully translated, yet. Please help completing the translation.** \\
+<font 14px/Arial, sans-serif;;initial;;#ffffff>The pulse is inverted in time. This corresponds to a horizontal reflection. In contrast, there is the "Change Polarity" function which mirrors vertically and thus inverts the amplitude.</font>
-//(remove this paragraph once the translation is finished)//
-====== Reversion ======
-\\
+<font 14px/Arial, sans-serif;;initial;;#ffffff>Here the time is inverted, thus the impulse is played "backwards".</font>
-**Description:**
 \\
-**Options:**
+<font 14px/Arial, sans-serif;;initial;;#ffffff>**Options:**</font>
+<font 14px/Arial, sans-serif;;initial;;#ffffff>-</font>
 \\
-**Application:**
+<font 14px/Arial, sans-serif;;initial;;#ffffff>**Use:**</font>
+<font 14px/Arial, sans-serif;;initial;;#ffffff>A temporal inversion is primarily used for phase correction / manipulation.</font>
+<font 14px/Arial, sans-serif;;initial;;#ffffff>The frequency response remains unaffected, but the phase is inverted as a mirror image.</font>
 \\
-**Example:**
+<font 14px/Arial, sans-serif;;initial;;#ffffff>**Example:**</font>
+<font 14px/Arial, sans-serif;;initial;;#ffffff>We invert the direction of our measurement:</font>
+<font 14px/Arial, sans-serif;;initial;;#ffffff>The purely min-phase loudspeaker becomes a purely excess-phase filter. If you convolve or filter the loudspeaker with this reversed pulse, the result is purely linear-phase, i.e. mirror-inverted. This can also be seen here in the inverted phase of both, as curve 2 (green) behaves more or less like a compensation filter:</font>
+{{:en:wiki:funktionen:td-functions:reversion6us5b.png?nolink&500x265}}
+{{:en:wiki:funktionen:td-functions:reversion_phasebts4f.png?nolink&500x261}}
+<font 14px/Arial, sans-serif;;initial;;#ffffff>(in the example above, both pulses were rotated on sample 0)</font>
+<font 14px/Arial, sans-serif;;initial;;#ffffff>In practice, however, the filter will be cleaned of amplitude and minphase beforehand in order to correct the pure excess phase distortion of the loudspeaker. This is done with "TD Functions - Extract Phase - Excess Phase" **after** the impulse has been windowed to a reasonable level beforehand (via Frequency Dependent Window).</font>