Drawing Number: 21210
Revision: NR
AN IMPROVED TECHNIQUE FOR
UTILIZATION OF CONFORMAL BALLISTICS
SENSOR CALIBRATION DATA
2
Figure 2: Zero based best straight
line method of linearity determination.
To utilize the zero based best straight line method, the
corresponding value of the sensor output is plotted for
each value of input measurand up to full scale as shown
in Figure 2.
A straight line, intercepting the origin as shown, is fitted
to the data points by equalizing the error between the
points below the line and the points above the line.
Error bands, as delineated by the instrument
specification are constructed as shown in figure 2.
Typically, plus and minus one or two percent of full
scale is specified for quartz sensors.
An acceptable instrument is then defined as one whose
data points all fall within this error band.
The "sensitivity" of an instrument so calibrated is simply
the full scale output (charge or voltage) divided by full
scale input pressure, where F.S. output is determined by
the straight line as defined above.
input
.
S
.
F
output
.
S
.
F
y
Sensitivit
(Eq. 1)
The units for sensitivity are commonly pC/psi or
mV/psi.
Note that in this case, the sensitivity is identical to the
slope of the line, since the line does intersect the origin
by previous definition.
The general equation for a straight line in terms of the
dependent variable is:
y = mx + b
(Eq. 2)
Figure 3
b in equation 2 is the y axis intercept.
m is the slope of the line defined as:
1
2
1
2
x
x
y
y
tan
θ
m
(Eq. 3)
Equation 2, expressed in terms of the independent
variable x is:
