corrupt.1

speech signal process tools

.\" Copyright (c) 1987 Entropic Speech, Inc.; All rights reserved
.\" @(#)corrupt.1	1.1	12/3/87 ESI
.TH CORRUPT 1\-ESPS 12/3/87
.ds ]W "\fI\s+4\ze\h'0.05'e\s-4\v'-0.4m'\fP\(*p\v'0.4m'\ Entropic Speech, Inc.
.ds ]Y "\fBESI INTERNAL\fP
.SH "NAME"
corrupt \- inject random bit errors in FEA_2KB bitstream file at specified
rate.
.SH "SYNOPSIS"
.B corrupt
[
.BI \-P " param_file"
][
.BI \-S " seed"
][
.BI \-h " hist_file"
]
.I " infile.fea outfile.fea"
.SH "DESCRIPTION"
.PP
\fICorrupt\fR injects random bit errors in the FEA_2KB serial bitstream
file \fIinfile.fea\fR, and writes the corrupted data to the FEA_2KB file
\fIoutfile.fea\fR. The error bits are designated by 1's in the \fIerror_mask\fR
field of the FEA_2KB record [see \fIfea_2kb\fR (5\-ESPS)]; no alterations to
the \fIbitstream\fR field of the record are performed. The corrupted data are
obtained from the exclusive OR of the \fIbitstream\fR and \fIerror_mask\fR
fields.
.PP
Error rates in the range from 1.0xE-3 to 1.0xE-6 can be specified. A uniformly
distributed random variable is used to generate the error stream. The program
generates only single-bit errors; burst errors are not simulated.
.PP
Random numbers are generated by calls to the library functions \fIsrandom\fR
(3C) and \fIrandom\fR (3C). The initial seed used in the call to \fIsrandom\fR
can be specified by the \fB\-S\fR option; otherwise, it is automatically
generated from the ESPS common file. This allows different results to be
produced on successive runs of the program, if desired. More details are
provided in the discussion below.
.PP
If \fIinfile.fea\fR is equal to "\-", standard input is used. If \fIoutfile.fea\fR
is equal to "\-", standard output is used.
.SH OPTIONS
.TP
.BI \-P " param_file"
Uses the ESPS parameter file \fIparam_file\fR, rather than the default,
which is \fIparams\fR.
.TP
.BI \-S " seed"
Causes the integer value \fIseed\fR to be used in the initial call to the
library funtion \fIsrandom\fR (3C). If this option is not invoked, the seed
is generated from the ESPS common file, as decribed below.
.TP
.BI \-h " hist_file"
Causes a listing of corrupted record numbers and corresponding error masks
to be placed in the file \fIhist_file\fR, instead of in the default file,
which is \fIcorrupt.his\fR.
.SH "ESPS PARAMETERS"
.PP
The parameter \fIerr_rate\fR is read from the parameter file. This is a
coded type, and may have one of the following string values: \fIZERO\fR,
\fI1.0xE-3\fR, \fI1.0xE-4\fR, \fI1.0xE-5\fR, or \fI1.0xE-6\fR. The values
correspond to the channel error rate that is to be simulated.
.SH ESPS COMMON
.PP
If the \fB\-S\fR option has not been invoked, the parameter \fIseed\fR is
read from the common file. If the parameter is defined, its value is
incremented prior to the call to \fIsrandom\fR (3C); otherwise, a value of
1 is used in the call to \fIsrandom\fR. The value of \fIseed\fR thus obtained,
or the value specified via the \fB\-S\fR option, is written back to the common
file. The string variables \fIfilename\fR and \fIprog\fR are also written to
ESPS common, where \fIfilename\fR takes on the value corresponding to
\fIoutfile.fea\fR, and \fIprog\fR has the value \fIcorrupt\fR.
.SH ESPS HEADERS
.PP
The header of \fIinfile.fea\fR is copied to the header of \fIoutfile.fea\fR.
The header of \fIinfile.fea\fR is added as a source in the output header,
and the command line is added to the comment field. The \fIerr_rate\fR item
in the generic header of \fIoutfile.fea\fR is set according to the value read
from the parameter file.
.SH WARNINGS
.PP
\fICorrupt\fR issues a warning and exits if \fIinfile.fea\fR is not a
FEA_2KB file.
.SH "SEE ALSO"
.PP
decode (1\-ESPS), encode (1\-ESPS), fea_2kb (5\-ESPS).
.SH "BUGS"
.PP
None known.
.SH "AUTHOR"
.PP
Program and manual page by Jim Elliott.