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A.
TOTALIZING
START- STOP SIGTAL
0tAiltJAL
coilTRoL)
B.
FREQUENCY
C.
PERIOD
D.
MULTI-PERIOD
AVERAGE
E.
RATIO
Section
II
Paragraphs 2-41
to
2-46
Figure
2-9.
Basic Counter Functions
2-10
Model 5245L
period.
The decimal point
is
positioned to give
the
readout
in
seconds,
milliseconds or microseconds
for
a
single period of the input signal.
2-41.
RATIO
MEASUREMENT. As
shown
in
Figure
2-98,
the frequency
ratio
of two
inputs
can
be meas-
ured bya
circuit
arrangement
similar tothat
used
for
period measurement.
One
input signal
is
applied
to
the main
gate
while the gating signal
is
made
equal
to
the period
(or
decade
multiple of the period)
of
the
other signal. The displayed countrepresents
the
num-
ber
of
cycles
of
one
inputwhich occur during
the
period
of one cycle (or decade
multiple of
one
cycle) of
the
other input.
2.42.
STANDARD FREQUENCY
OUTPUTS. Multi-
plier
and
decade
divider circuits
connected
to
the
internal l
MHz
oscillator provide
output frequencies
from
10
MHz
to
0.
I Hz
(in
decade
steps) using
the
arrangement
shown
in Figure
2-10.
2-43.
SCALER OPERATION. An
input
can
be scaled
by
a
factor from
10
to tg9 (in
decade
steps) using
the
arrangement
shown
inFigure
z-tL.
Note
that
thefirst
two divisions
are
done
by
the
high-speed decimal
counters
which in this
case
function
as
decade
dividers.
2-44.
TtfilE
SEQUENCE.
2'45.
GENERAL. Folloving a
counter measurement
there are several operations which occur in
a
partic'
ular
sequence. The pulses which control these oper-
ations
and
their time
relation to
each
other are
shovrn
in Figure
2-L2.
The
trailing
edge
of
the gating
pulse
(end
of
count
)
triggers
the one-shot multivibrators
(Paragraph
2-19)
which generate these pulses.
2-46. TRANSFER. The transfer multivibrator
is
triggered at the
end of the gating signal,
and
it
pro-
duces
a
35-millisecond
pulse.
The
transfer
pulse
is
applied
to the
decimal counters
to transfer
the
new
count
to the
display.
During
a
measurement function
the
count
is
stored
in the
storage binaries until
the
transfer pulse
allorvs the new
count
to
be
displayed.
Figure
2-L0.
Standard Frequency
Outputs
02349-1
o5243-A-rI
O!ea
5-
3-
lO
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