Heathkit IO-4550 - Page 16

Page 14
Example 6
TIME/CM-To-Frequency Correlation
Eleven vertical and nine horizontal lines on the graticule,
spaced 1 centimeter apart, permit the measurement of
displayed waveforms. The short markers on the centerlines
are spaced 2 millimeters apart. Use the following formula to
determine the frequency of a waveform displayed on the
CRT.
TIME/CM switch*
setting in seconds
per cm.
1
- MAGNIFIER
Centimeters for 1 Period of
X cycle of unknown = unknown
frequency frequency.
pare sie
and, Period ~ Frequency
EXAMPLE: If one cycle of a waveform measures 2 cm on
the graticule, with the TIME/CM switch at 1 mS and the X5
switch pulled out, then —
sey]
7
1
001°"
X
5
X
2
=
.0004,
and
0004
= 2500 Hz.
NOTES:
“The VARIABLE —X5 control must be fully clockwise to
use the calibrated TIME/CM switch settings in this formula.
**1 millisecond = .001 second; 1 microsecond = .000001
second.
When the X5 switch is pulled out, the sweep travels 5 times
further. (theoretically), which makes the sweep time shorten
by a factor of 5.
q
)