ref: 41bb7cc1dd2f4ec895d9ef7340534eec236e3270
parent: 8617bb82be282bc354e716a11cb92fa5e3006c96
author: Rob Sykes <robs@users.sourceforge.net>
date: Thu Dec 29 06:16:30 EST 2011
sinc filter: clarify usage in light of recent sox-users discussion; add soft-break for better rendering in 80 columns
--- a/sox.1
+++ b/sox.1
@@ -3086,7 +3086,7 @@
.EE
.na
.TP
-\fBsinc\fR [\fB\-a\fI att\fR\^|\^\fB\-b\fI beta\fR] [\fB\-p\fI phase\fR\^|\^\fB\-M\fR\^|\^\fB\-I\fR\^|\^\fB\-L\fR] \:[\fB\-t\fI tbw\fR\^|\^\fB\-n\fI taps\fR] [\fIfreqHP\fR][\fB\-\fIfreqLP\fR [\fB\-t\fR tbw\^|\^\fB\-n\fR taps]]
+\fBsinc\fR [\fB\-a\fI att\fR\^|\^\fB\-b\fI beta\fR] [\fB\-p\fI phase\fR\^|\^\fB\-M\fR\^|\^\fB\-I\fR\^|\^\fB\-L\fR] \:[\fB\-t\fI tbw\fR\^|\^\fB\-n\fI taps\fR] [\fIfreqHP\fR]\:[\fB\-\fIfreqLP\fR [\fB\-t\fR tbw\^|\^\fB\-n\fR taps]]
.ad
Apply a sinc kaiser-windowed low-pass, high-pass, band-pass, or band-reject filter
to the signal.
@@ -3093,8 +3093,17 @@
The \fIfreqHP\fR and \fIfreqLP\fR parameters give the frequencies of the
6dB points of a high-pass and low-pass filter that may be invoked
individually, or together. If both are
-given, then \fIfreqHP\fR < \fIfreqLP\fR creates a band-pass filter,
-\fIfreqHP\fR > \fIfreqLP\fR creates a band-reject filter.
+given, then \fIfreqHP\fR less than \fIfreqLP\fR creates a band-pass filter,
+\fIfreqHP\fR greater than \fIfreqLP\fR creates a band-reject filter.
+For example, the invocations
+.EX
+ sinc 3k
+ sinc -4k
+ sinc 3k-4k
+ sinc 4k-3k
+.EE
+create a high-pass, low-pass, band-pass, and band-reject filter
+respectively.
.SP
The default stop-band attenuation of 120dB can be overridden with
\fB\-a\fR; alternatively, the kaiser-window `beta' parameter can be