rem_dc.1

speech signal process tools

.\" Copyright (c) 1989 Entropic Speech, Inc.; All rights reserved
.\" @(#)rem_dc.1	3.6	1/4/93 ESI
.TH REM_DC 1\-ESPS 1/4/93
.ds ]W "\fI\s+4\ze\h'0.05'e\s-4\v'-0.4m'\fP\(*p\v'0.4m'\ Entropic Speech, Inc.
.SH NAME
rem_dc \- remove the DC component from an ESPS sampled data file.
.SH SYNOPSIS
.B rem_dc
[
.BI \-x " debug_level"
]
[
.BI \-r "r range"
]
[
.BI \-p " xrange"
]
[
.BI \-l " yrange"
]
[
.BI \-a " offset"
]
.I in_file out_file
.SH DESCRIPTION
.PP
The program
.I rem_dc
takes the ESPS sampled data file
.I in_file,
computes the DC offset of the data, subtracts it from each data point,
and places the resulting data in
.I out_file.
The program can optionally adjust the DC offset to a user specified value.
The program enters the total adjustment in the header of
.I out_file.  A temporary file is created (and removed) in the directory
specified by the environment variable ESPS_TEMP_PATH (default /usr/tmp).  
.PP
If 
.I in_file
is "\-", 
then the standard input is read.  If
.I out_file
is "\-", the program writes to standard output.
.SH OPTIONS
The following options are supported:
.TP
.BI \-x " debug_level"
A value of 0 (the default value) will cause
.I rem_dc
to do its work silently, unless there is an error.
A nonzero value will cause various parameters to be printed out
during program initialization.
.br
.TP
.BI \-p " xrange"
The range of points to compute the DC value over, remove the DC
value from, and copy to the output file.  The
.I xrange
argument is a text string which obeys all the conventions used by the
.I range_switch (3-ESPSu)
function.  The default values for the beginning and ending points of 
.I xrange
are the first and last data points in the file.
.br
.TP
.BI \-r " xrange"
\fB\-r\fP is a synonym for \fB-p\fP.
.br
.TP
.BI \-l " yrange"
Only data points whose values fall in the specified range will be used to compute
the DC component.  This allows the user to use only small magnitude numbers, for
example, to obtain a more accurate result.  The 
.I yrange
argument is a text string which obeys all of the conventions used by the
.I frange_switch (3-ESPSu)
function.  The default values for the upper and lower limits of
.I yrange
are the maximum and minimum values in the file.
.br
.TP
.BI \-a " offset"
The DC component is adjusted to
.I offset.
The default value for
.I offset 
is 0.0.
.br
.SH ESPS PARAMETERS
The parameter file is not accessed.
.SH ESPS COMMON
If standard input is not specified, the following items are read from 
ESPS Common:
.IP \fIfilename - string\fR
This is the name of the input file. If no input file is specified on the
command line, \fIfilename\fR is taken to be the input file name.
If an input file is specified on the command line,
the input file name must match \fIfilename\fR
or other items (below) are not read from Common.
.IP \fIstart - integer\fR
This is the starting point in the input file to begin processing.
It is not read if the \fB\-p\fR option is used.
.IP \fInan - integer\fR
This is the number of points to process. It is not read if the
\fB\-p\fR option is used.
.PP
If \fIstart\fR and/or \fInan\fR are not given in the Common file,
then \fIstart\fR defaults to the beginning of the file and
\fInan\fR defaults to the number of points in the file.
.PP
If standard output is not specified,
the following items are written to the ESPS Common:
.IP \fIstart - integer\fR
One is written to the Common file.
.IP \fInan -integer\fR
The number of points processed by \fIrem_de\fR is written
to the ESPS Common.
.IP \fIfilename - string\fR
The name of the output file is written to ESPS Common.
.PP
ESPS Common processing may be disabled by setting the environment variable
USE_ESPS_COMMON to "off".  The default ESPS Common file is .espscom 
in the user's home directory.  This may be overidden by setting
the environment variable ESPSCOM to the desired path.  User feedback of
Common processing is determined by the environment variable ESPS_VERBOSE,
with 0 causing no feedback and increasing levels causing increasingly
detailed feedback.  If ESPS_VERBOSE is not defined, a default value of 3 is
assumed.
.SH ESPS HEADER
All appropriate input file header items are copied to the output file header.
Also,
the \fIdc_removed\fP (type DOUBLE) and \fIstart_time\fP (type DOUBLE)
are also added or updated.
A \fImax_value\fP generic header item is added by 
\fIrem_dc\fP (1\-\s-1ESPS\s+1).
.SH BUGS
.PP
None known.
.SH AUTHOR
Brian Sublett; modified for ESPS by David Burton.