meter.1

speech signal process tools

.\" Copyright (c) 1993 Entropic Research Laboratory, Inc.; All rights reserved
.\" @(#)meter.1	1.3 6/23/93 ERL
.ds ]W (c) 1993 Entropic Research Laboratory, Inc.
.TH  METER 1\-ESPS 6/23/93
.SH NAME

.nf
meter \- a control panel for ESPS A/D recording programs
.fi
.SH SYNOPSIS
.B
meter
[
.BI \-i " update_time"
] [
.BI \-c " RC_const"
] [
.BI \-s
] [
.BI \-m
] [
.BI \-r
] [
.I -
]
.I outfile
.PP
.SH DESCRIPTION
\fIMeter\fR is a front-end program to be used with any ESPS recording
program to control its recording process and to visually monitor input 
signal amplitude
in decibels.  Input to \fImeter\fR is always the standard input which
may be optionally specified on the command line as "-" before the output
file name \fIoutfile\fR.  If \fIoutfile\fR is "-", standard output is
written.
.PP
\fIMeter\fR is a X-window based program compiled for the Motif version 
1.1.3 and X11R4.
When executed, the program pops up a panel with the following control
and monitoring featurers:
.PP
A "Start/Restart" pushbutton to start and restart the recording.  Input to
\fImeter\fR will not be written out to \fIoutfile\fR unless the "Start"
push button is activated.  Activating the button after the first time will
cause the file stream pointer to rewind and rewrite to \fIoutfile\fR,
thus restarting the recording process.  A message of "Recording...." is
shown on the panel while writing to \fIoutfile\fR is in progress.
.PP
A "Pause/Resume" pushbutton to pause and resume the recording.
A message of "Recording...." is shown on the panel while writing to 
\fIoutfile\fR is in progress.
.PP
Two input dB-level meters representing channel 1 and channel 2.  Each
meter gives a visual indication of input dB level by means of a rising and
falling green bar with grey background along with its numerical readout.  
If the input dB level exceeds 90 dB, then
the top region of meter, normally black, turns into red color to indicate
that signal clipping has occured and input signal amplitude should be
turned down.
An additional falling
thin green line indicates the decay of the last maximum input value
with an exponential rate of \fI-RC_const\fR.
By default, the meter display updates every 0.1 second, but
changeable by the \fB-i\fR option.  Input is always assumed to be the
data type SHORT.  The top region of the meter become red in the event of
clipping.
.PP
Three toggle buttons: A "DC-offset" toggle button to remove DC component of
input signal before writing to \fIoutfile\fR, a "meter" toggle button to
disable the meter display, and a "meter db readout" toggle button to
disable the numerical dB value readout.
.PP
A "Stop/Quit" button to exit the program.  When this button is pressed, \fImeter\fR
closes input and output file stream pointers, this may cause ESPS recording
program to display a write-error message since it can no longer write to
standard output.  Ignore the message in such case.
.PP
The success of executing the program depends on the CPU load
of the machine.  If \fImeter\fR can not keep up with the input, an error
message from the recording program is displayed to standard error, 
and the recording process halts.  In such cases, decrease the CPU load
by killing other jobs on the machine, increasing
the time interval between meter display updates by the \fB-i\fR
option, or turning "DC-offset", "meter", or "meter db readout" toggle button 
to off.
.PP
.SH OPTIONS
.PP
The following options are supported:
.TP
.BI \-i " update_time \fR[0.1]\fP"
\fIMeter\fR updates its display every \fIupdate_time\fR second.  
\fIupdate_time\fR is in increment of 0.1 seconds.  The smallest value is 0.1.
.TP
.BI \-c " RC_const \fR[0.1]\fP"
The falling exponential rate of the thin green line.  This must be a 
non-negative number.  At each display update, the green line has the dB
value of the previous maximum input level times 
\fIexp(RC_const*time)\fR, where \fItime\fR is the elapsed time since
the last maximum occured.
.TP
.BI \-s
To set the default state of "DC-offset" toggle button from OFF to ON.  
\fIRem_dc (1-ESPS)\fR may also be used to remove the DC component in the
signal after the recording is done.
.TP
.BI \-m
To set the default state of "meter" toggle button from ON to OFF.
.TP
.BI \-r
To set the default state of "meter db readout" toggle button from ON to OFF.
.PP
.SH ESPS PARAMETERS
No ESPS parameter file processing is supported.
.PP
.SH ESPS COMMON
No ESPS common parameter processing is supported.
.PP
.SH ESPS HEADERS
ESPS header from the standard input is copied to \fIoutfile\fR without
change.
.PP
.SH EXAMPLES
The following monitors signal input level of Sun Sparc 8-bit 
mu-law A/D converter.
.TP
srecord - |Meter /dev/null
.PP
.SH ERRORS AND DIAGNOSTICS
.PP
.SH BUGS
.PP
None known.
.SH REFERENCES
.PP
.SH "SEE ALSO"
rem_dc (1-ESPS), v32record (1-ESPS), c30record (1-ESPS), 
s32crecord (1-ESPS), srecord (1-ESPS), sgrecord (1-ESPS)
.PP
.SH AUTHOR
Derek Lin
.PP