.TH E1432_SET_RPM_SMOOTHING 3 E1432
.SH NAME
.nf
e1432_set_rpm_smoothing \- Set tach time smoothing factor
e1432_get_rpm_smoothing \- Get tach time smoothing factor
.fi
.IX e1432_set_rpm_smoothing(3) 3
.IX e1432_get_rpm_smoothing(3) 3
.SH SYNOPSIS
.cS
SHORTSIZ16 e1432_set_rpm_smoothing(E1432ID hw, SHORTSIZ16 ID,
                             		FLOATSIZ32 smoothing)
SHORTSIZ16 e1432_get_rpm_smoothing(E1432ID hw, SHORTSIZ16 ID,
                             		FLOATSIZ32 *smoothing)
.cE
.SH DESCRIPTION
\fIe1432_set_rpm_smoothing\fR sets the tach time smoothing factor used for 
calculating RPM values in the RPM arming modes.

\fIe1432_get_rpm_smoothing\fR returns the tach time smoothing factor into 
the variable pointed to by \fIsmoothing\fR.

\fIhw\fR must be the result of a successful call to
\fIe1432_assign_channel_numbers\fR, and specifies the group of
hardware to talk to.

\fIID\fR is either the ID of a group of channels that was obtained
with a call to \fIe1432_create_channel_group\fR, or the ID of a single
channel.

\fIsmoothing\fR specifies the smoothing factor.  It's legal values range
from 0.0 to 1.0.

When the smoothing factor is non-zero, tach times are calculated using a
weighted "average" of previous smoothed tach times and the new raw
tach time obtained from the AYF tachometer option.  This smoothing operation
takes the "jitter" out of tach times obtained from real world tachometers.
The smoothed tach time is calculated in the following fashion:

.nf
Traw = current raw tach time from tach board
Tn-1 = previously calculated tach time 
Tn-2 = calculated tach time before that
Tn   = current tach time to be calculated

Tn = Traw * (1.0 - smoothing) + (2Tn-1 - Tn-2) * smoothing
.fi
.SH "RESET VALUE"
After a reset, \fIsmoothing\fR is set to 0.0.
.SH "RETURN VALUE"
Return 0 if successful, a (negative) error number otherwise.
.SH "SEE ALSO"
.na
e1432_get_rpm_smoothing_limits
.ad
