TFT 844 - Page 10

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3.1
General
SECTION
3
OPERATION
The
Model
844
FM
Modulation
and
Stero Monitor
enables
FM
station
personnel
to
monitor
FM
and
Stereo Transmissions
to
comply
with
FCC
rules
and
regulations.
The
monitor provides
all
the
test
functions required for modulation
and
stereo
proof-of-performance
tests.
When
used
with
model
730A
SCA
Monitor
SCA
proof-of-Permance
test
may
also
be
made.
Monitor displays the modulation percentage of the
selected
carrier
being monitored.
Two
front-panel
LED
1
s provide a
flashing indication
when
the modulation percentage exceeds a pre
set
limit
on
either
positive or negative peaks. Right
and
left
channel can
be
monitored simultaneously or the
LEFT/TEST
meter
can
monitor
any
of
the other
test
functions of th monitor.
3.2
Turn-On
and
Warm-Up
The
monitor contains
no
On-Off
switch,
and
is
on
whenever
it
is
plugged into the appropriate
power
source. Indications
of
the unit having
power
on
are
1)
Meter
lights
on.
2)
One
of
the
two
green channel
select
LED's
on.
3)
Peaks/Min
digital
readout on.
3.3
3.3.1
Ref.
No.
1.
2.
3.
Controls, connectors
and
Indicators
Model
844
Front
Panel
(See Fig .
3-1)
Name
Function
TOTAL
MODULATION
meter Indicates modulation
percentage of
carrier
being
monitored.
11
-
11
PEAKS
1
amp
PEAK
CALI
adjust
-9-
"-" peaks
lamp
shows
whenever
the negative
modulation peaks
exceed
the
percentage
which
the
thumb-
wheel
switchs
has
been
set.
Calibrate the
11
-
11
and"+"
peak
lamps
on
point.