TFT 844 User manual
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SECTION
1
SECTION
2
SECTION
3
TABLE
OF
CONTENTS
GENERAL
INFORMATION
1.1
1.2
1.3
1.
3.1
1. 3.2
1.4
1.5
General Description
Specifications
Accessory
Equipment
Model
730A
SCA
Monitor .
Model
804
Remote
Metering Panel
Warranty
.•...
Claim
for
damage
in Shipment
INSTALLATION
2.1
Unpacking
and
Inspection . . . .
2.2
Power
Requirements . .
. . .
2.3
Installation
and
Connections
2.4 Connection of Accessory
Equipment
2.4.1
Connection
of
Model
730A
SCA
Monitor .
2.4.2
Connection of
Model
804
Remote
Metering
Panel . . .
. .
.
.
. .
2.5 Field
Installation
of
Options . . . . .
OPERATION
3.1 General . . . . . . . . . . .
3.2
Turn-On
and
Warm-Up.
. .
. .
.
. .
3.3 Controls, Connectors
and
Indicators
3.3.1
Model
844
Front Panel
3.3.2
Model
844
Rear
Panel
3.4 Calibration . . . . . . . . . .
3.4.1
Meter Calibration .
. .
3.4.2
Peak
Modulation
Calibration.
. . . .
3.5 Measurements . . . . . . .
3.5.1
Main
Channel
Modulation
(L
+
R)
. .
3.5.2 Stereo Subchannel Modulation
(L
-R).
3.5.3
Pilot
Carrier Modulation
3.5.4
38
KHz
Subcarrier Suppression ..
3.5.5 Stereo Separation . . . .
3.5.5.1
Stereo
Channel
Separation
(left
Channel
Modulated) . . . . .
.
. . .
3.5.5.2
Stereo
Channel
Separation (Right
Channel
Modulated) .
. .
. .
.
.
. .
3.5.6
Main
Channel
to
Subcarrier Crosstalk
3.5.7
Subcarrier
to
Main
Channel
Crosstalk
3.5.8
FM
Noise
3.5.9
Distortion . . . . . .
3.5.
10
Pilot
Frequency.
.
.
.
3.5.
11
Peak
Modulation .
.
3.5.12 Incidental
And
Residual
AM
3.5.13
Multipath
Noise.
. . . .
.....
3.6
Absence
of Modulation
Alarm
(Optional).
3.7 Carrier Failure
Alarm
(Optional). . . .
3.8
Use
of
Remote
Metering Panel.
Model
804
-2-
.
. . .
.
3
3
5
5
6
6
6
7
7
7
7
8
8
8
9
9
9
9
12
13
14
14
14
14
14
15
15
15
15
16
16
16
17
17
17
18
18
18
19
19
19
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SECTION
1
GENERAL
INFORMATION
1.1 General Description
The
TFT
Model
844
FM
Modulation
stereo
monitor
provides both
on-the-air
and
off-the-air
monitoring of
FM
broadcast
stations
operating in
the
frequency range
of
88
to
108
MHz.
The
three
meter format allows
stereo
measurements
while monitoring
total
modulation, Left
and
Right channels.
Push
button switches allow monitoring of the following functions
on
the
LEFT/TEST
Meter:
left
Channel, Right Channel, 38
kHz,
19
kHz
pilot,
L+R,
L-R,
Total modulation,
AM
noise,
and
multipath.
Front panel
indicators
show
when
a preset
modulation percentage
is
exceeded
on
either
positive
or
negative
peaks.
Front panel controls allow the monitoring of
two
different
frequencies without
resetting.
Absence
of modulation
and
carrier
failure
alarms
are available
as
options.
1.2
Specifications
RF
SECTION
Frequency range
.....
On-site
RF
input voltage
Antenna
input voltage
Tuning
.
.......
.
AGC
range
.......
.
Input impedance, antenna
Input connector, antenna
MODULATION
METERS,
TOTAL
Deviation
for
100%
indication
Meter
Range
.•...••
AC
Voltmeter range .
Accuracy
(5-KHz
tone)
Frequency response
Characteristics
.
Remote
output .
. 88-108
MHz,
tunable in
50
KHz
steps
. 1
to
10
volts
rms
250
uV
to
lOOmV
Two
4-digit
switches
and
a push-
button switch for
selecting
station
Aor B.
. 60
dB
75
ohms
Type
F
• +
75
KHz
peak
to
peak
•
1Y
to
133%
modulation
.
Oto
-50
dB
in
10
dB
steps
. +
2%
at
all
modulation
levels
+ 0.1
dB
typical,+
0.
25
dB
max
from
50
Hz
to
120
KHz
-
Quasi-peak reading
circuit
Suitable for driving remote readout
meter panels.
-3-
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MODULATION
METERS,
RIGHT
Right channel modulation
MODULATION
METER,
LEFT/TEST
Left channel modulation .
Right channel modulation
Main
channel
..•.
L + R • • • • •
L - R • • • •
Indicates
and
measures
right
channel
modulation
. Indicates
and
measures
left
channel
Modulation
.
Same
as
right
modulation meter
.
Same
as
total
modulation meter
• + 0.35
dB,
50
Hz
to
15
KHz
. + 0.35
dB,
23
KHz
to
53
KHz
38
KHz
1
eve
1• • • • • • •
Pilot
level
..
••.•
'Reasure
down
to
-60
dB
•
Measure
down
to
-60
dB
Phase
calibration
. .
For
optimization of
stereo
measurements
AM
noise
..•.
Multipath
indicator
. .
Measures
AM
noise
PEAK
MODULATION
INDICATORS
Deviation for
100%
indication
.
Peak
level
........
.
Accuracy
(5-KHz
tone) .
Frequency response
Response
time accuracy
Remote
flasher
output
Peak
counter
.
For
adjustment of antenna to minimize
multipath
distortion
. +
75
KHz
.
-S-et
by
a
front
panel
3-digit
thumb-
wheel
switch in
1%
steps
from
0%
to
199%
on
both
positive
and
negative
peaks
. +
2%
at
100%
modulation
. +
2%
from
30
Hz
to
120
KHz
. Adjustable,
10
cycles
of
10
KHz
or
faster
. Suitable for driving
two
remote meter
panels
Registers
number
of
peaks
per minute
MODULATION
CALIBRATOR
Built
in frequency synthesized
calibrator
for
meter
and
peak
flasher
calibration
of
100%
modulation
from
the
front
panel . Accuracy
,::1%
.
MEASUREMENT
OF
RESIDUAL
AM
Range
. . . . • . . • . .
Accuracy
(at
-30dB)
...
OUTPUTS,
FRONT
AND
REAR
PANEL
Main
channel output with
75
sec de-emphasis
*Signal
to
noise
ratio
..
.
*Harmonic
distortion
..
. .
*Intermodulation
distortion
*Frequency response . . . . .
. 0
to
70
dB
• + 1
dB
5
volts
rms
into
SK
ohms
at
400
Hz
.
78
dB
at
400
Hz
with de-emphasis
.
0.1%
max
(de-emphasized)
• 0.
1%
max
per
SMPTE
standard
+0.25
dB
from
30
Hz
to
120
KHz
composite
-4-
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*Balanced audio output level
...
*Balanced audio frequency
response
.......
.
SCA
output
at
rear
panel
Audio
(with de-emphasis)
left
and
right
.....
Audio
(without de-emphasis)
1
eft
and
right
Pilot
carrier
(19
KHz).
Composite
. .
Remote
meter
Connectors
Meter
output
Carrier-failure
alarm. optional
Absence
of
modulation
a1
arm.
optiona1 • •
STEREO
SEPARATION
AND
CROSSTALK
Separation L-to-R
and
R-to-L.
Crosstalk
(L+R)
to
(L-R)
or
(L-R)
to
(L+R)
•..
Crosstalk
SCA
to
(L+R)
or
SCA
to
(L-R)
...•
Pilot
carrier
measurement
leve1 accuracy . . . .
MECHANICAL
AND
ENYIROtf'IENTAL
Input
power
.....
Operating temperature • •
Size . . . . .
Net
Weight
Shipping weight .
0
dBm
into
600
ohms.
+0.5
dB
from
30
Hz
to
120
KHz
. T
volt
rms
into
600
ohms
. 1 V
RMS,
600
ohms
unbalance
at
100%
modulation
(400
Hz)
. 1 V
RMS,
600
ohms
unbalanced at
100%
modulation.
600
mV
RMS,
available
on
front
panel
5 V
RMS,
lOK
ohms
at
100%
modulation
.
For
Model
804
remote meter panel
BNC
Main
meter selected signal available
on
front
pane
1•
. Relay drive output capable of sinking
50
mA
to
30
V
DC
when
RF
carrier
drops
below
50%
of
nominal.
An
output capable
of
sinking
50
mA
at
30
V
DC
when
composite signal drops
below
30%
modulation for a period
of
time
between
2 sections
and
1 minute,
internally
adjustable.
60
dB
typical,
55
dB
minimum,
50
Hz
to
15
KHz
.
65
dB
min
•
70
dB
min
+0.5%
from
6%
to
12%
injection
117/230
+10%
VAC,
50
to
400
Hz.
40
watts-max
0°C
to
50°C
(32°F
to
122°F}
.
7"
(17.78cm) high x
19"
(48.26cm)
wide
x
15"
(38.10cm)
deep
Approximately
18.5
pounds
(8.4
Kg)
Approximately 22.5
pounds
(10.
2Kg)
1.3
Accessory
Equipment
1.3.1
Model
730A
SCA
Monitor
The
Model
730A
enables
FM
stations
broadcasting
SCA
information
on
the
carrier
to
meet
all
FCC
SCA
requirements.
The
model
844
provides
a
composite
input
to
the
model
730A.
-5-
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1.3.2
Model
804
Remote
Metering Panel
The
Model
804
duplicates
flasher
and
meter readings
and
comes
with
50
feet
of cable
(TFT
Part
No
. 51160-0804)
1.4
Warranty
TIME
&
FREQUENCY
TECHNOLOGY,
INC.,
warrants each
of
the instruments of
its
manufacture to
be
produced
to
meet
the
specifications
delivered
to
the
BUYER;
and
to
be
free
from
defects
in
material
and
workmanship
and
will
repair
or
replace,
at
its
expense,
for
a period
of
one
year
from
the date
of
delivery
of
equipment,
any
parts
which
are defective
from
faulty
material or
poor
workmanship.
Instruments
found
to
be
defective during the
warranty period shall
be
returned to the
factory
with
transportation
charges prepaid
by
BUYER.
It
is
with respect to
any
nonconforming
equipment
and
parts thereof
and
shall
be
in
lieu
of
any
other
remedy
available
by
applicable
law.
All
returns
to the factory
must
be
authorized
by
the
SELLER,
prior
to
such
returns.
Upon
examination by
the
factory,
if
the instrument
is
found
to
be
defective,
the unit will
be
repaired
and
returned
to
the
BUYER,
with
transportation
charges
prepaid
by
SELLER.
Transportation charges for instruments
found
to
be
defective within the
first
thirty
(30) days
of
the warranty period will
be
paid both
ways
by
the
SELLER.
Transportation charges for warranty
returns,
wherein
failure
is
found
not
to
be
the
fault
of the
SELLER,
shall
be
paid both
ways
by
the
BUY"'tlr.'"
NO
OTHER
WARRANTY
IS
EXPRESSED
OR
IMPLIED.
TFT
IS
NOT
LIABLE
FOR
CONSEQUENTIAL
DAMAGES.
1.5
Claim
for
Damage
in shipment
Your
instrument should
be
inspected
and
tested
as
soon
as
it
is
received.
The
instrument
is
insured for safe
delivery.
If
the instrument
is
damaged
in
any
way
or
fails
to operate properly,
file
a claim with the
carrier,
or
if
insured separately, with the
insurance
company.
WE
SINCERELY
PLEDGE
OUR
IMMEDIATE
AND
FULLEST
COOPERATION
TO
ALL
USERS
OF
OUR
PRECISION
ELECTRONICS
INSTRUMENTS.
PLEASE
ADVISE
US
IF
WE
CAN
ASSIST
YOU
IN
ANY
MANNER.
T
FT
Inc.
3090
Oakmead
Village Drive
Santa Clara,
CA
95051
(408)
727-7272
-6-
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2.1
SECTION
2
INSTALLATION
Unpacking
and
Inspection
Upon
receiving the instrument, inspect the packing
box
and
instrument for signs
of
possible shipping
damage.
After
installation,
operate the instrument in accordance with the procedures
of Section 3 of
this
manual.
If
the instrument
is
damaged
or
fails
to
operate properly,
file
a claim with the transportation
company,
or with
the insurance
company
if
insured separately.
2.2
Power
Requirements
The
model
844
is
factory wired to operate,
from
either
a
117
volt or
230
volt source.
The
line frequency
must
be
between
50
and
400
Hz
.
Maximum
Power
required
is
40
watts.
2.3
through
Jl3.
operation.
Installation
and
Connection
(A)
Mount
the
Model
844
in the
equipment
rack.
(B)
AC
Power
is
applied
to
rear
of the unit
Either
117
VAC
or
230
VAC
are required for proper
CAUTION
THE
CIRCUIT
BOARD
BELOW
THE
FUSE
IN
Jl3
MUST
READ
THE
VOLTAGE
TO
BE
USED
AS
PRIMARY
POWER.
117
VAC
OR
230
VAC
.
THIS
BOARD
MAY
BE
REMOVED
AND
TURNED
FOR
PROPER
VOLTAGE.
CAUTION
FUSE
VALUES
DIFFER
AT
THE
VARIOUS
OPERATING
VOLTAGES
AND
MUST
BE
CHANGED
WHEN
CHANGING
INPUT
POWER
CONNECTION
IN
Jl3
.
(C)
For
continuous monitoring, connect
FM
antenna
to
low
level
RF
input
Jll
on
monitor rear panel.
{D)
For
off
air
{high Level)
measurements
connect
RF
high level input
(1
to
10
V
RMS)
to
high level
RF
input
J12
on
844
rear
panel . Adjust
RF
input
set
until green
LED
on
rear
panel
is
on.
NOTE
HIGH
LEVEL
INPUT
REQUIRES
PROPER
CRYSTAL
TO
BE
INSTALLED
IN
THE
MONITOR
2.4 Connection of Accessory
Equipment
-7-
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2.4.1 Connection
of
Model
730A
SCA
Monitor
Connection to
Model
730A
SCA
Monitor
is
made
by
taking composite output
at
J4
(to
SCA
Monitor)
and
applyi
ng
to
the
Model
730A.
2.4.2 Connection
of
Model
804
Remote
Metering
Panel
Connection
to
Model
804
Remote
Metering
Panel
is
made
to
TBl
on
844
Rear
Panel.
2. 5 Field
Installation
of
Options
TO
BE
PUBLISHED.
-8-
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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.
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4.
11
+
11
PEAK
lamp
5.
Th1.JT1bwheel
switches
6.
PEAK/MIN
counter
7.
LEFT/TEST
meter
8.
RIGHT
Channel
meter
9.
RIGHT
OUTPUT
jack
10.
LEFT/TEST
OUTPUT
jack
11.
STEREO
PILOT
lamp
12.
LEFT/TEST
METER
function
"+"
peak
1
amp
shows
whenever
the
positive
modulation
peaks exceed the percentage
which
the
thumbwheel
switches
has
been
set.
Sets the percent of
modulation at
which
the
11
+
11
and
11
-
11
peak
1
amps
on
point.
Counts
the
number
of
times
the
peak
lamps
on
over a
given period.
Indicates
the
function
switched in
by
the
LEFT/TEST
METER
function switches.
Input
to
this
meter
is
always
applied through a
selected
attenuator.
Measurements
can
be
made
down
to
70
dB
below
100%.
Indicates
right
channel
modulation independent of
selected function switch
position.
Right channel signal
supplied to front panel
BNC
jack.
Signal selected
by
LEFT/TEST
METER
function
switches
is
supplied
to
front
panel
BNC
jack.
Lights
when
19
KHz
pilot
signal
is
present.
Selects the function
and
attenuation
to
be
indicated
on
the
LEFT/TEST
METER
up
to
four switches
may
be
in uses
at a time.
1)
11
+
11
or
11
-
11
select
positive
or negative
modulation peaks .
2)
Deemph
switches in
the
deemphassis
circuit.
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13.
METER
CAL
adjust
14.
PHASE
CAL
adjust
15.
ANT
INPUT
LEVEL
16.
PEAKS/MIN
RESET
17.
CHAN
SELECT
switch
18.
Channel
Indicator 1ights
19.
FREQ
ADJ
20.
FREQ
COUNTER
-11-
3)
Attenuation switches
from
odb
to
-50
(100%
to
.3%}
inserts
the attenuation
marked
resulting
in
the
algebraic
sum
of
signal
and
attenuation.
4)
Signal
select
provides
the selected signal
to
the
meter.
Used
to
calibrate
the
all
three meters to
100%
modulation.
When
the phase cal switch
is
depressed the phase cal
control can
be
adjusted for
a null
on
the
LEFT/TEST
meter.
To
indicate
that
the
internal 38
KHz
signal
is
in
phase with the
19
KHz
pilot
signal.
This insures
that
the best channel separation
has
been
attained
so
that
the best
stereo
measurements
can
be
made.
Indicates the level of the
RF
from
the antenna
on
the
total
modulation meter.
(Push
to read switch).
Resets the peaks
min
counter.
Allow
selection
of
one
of
the
two
channels selected
by
the
programmable
thumbwheel
switches.
Lighted
lamp
indicates
which
frequency
has
been
selected.
Read
thumbwheel
sw
itches.
Control
to
adjust the
frequency of the 9.80
KHz
oscillator
circuit.
Selects
from
3 frequencies
which
can
be
supplied to the
freq. counter
BNC
on
front
panel:
1)
900
KHz,
2)
9.80
KHz
and
3)
19.0
KHz.
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21.
22.
3.3.2
Ref.
No.
23.
24.
25.
26.
27.
28.
29.
30.
31.
FREQ.
COUNTER
jack
Thumbwheel
switches
Model
844
Rear
Panel
Name
RF
INPUT-LOW
LEVEL
jack
HI
LEVEL
RF
INPUT
SET
Lamp
RF
INPUT-HIGH
LEVEL
jack
HIGH
LEVEL
RF
INPUT
SET
control
FUSE
and
AC
VOLTAGE
SET
AC
POWER
CORD
CONNECTOR
High
level operating
frequency
COMPOSITE
jack
To
SCA
Monitor jack
_12-
BNC
connector supplies
selected frequency
for
connection to a frequency
counter.
The
two
rows
of
thumbwheel
switches allow
of
two
channels.
(See Fig. 3-2)
Function
Used
to
connect
an
antenna
input with signal level
between
10
and
100
MV
(75
ohm)
Lamp
indicates
when
the high
level
RF
input level
has
properly
been
adjusted.
Used
to
connect signal input
with level
between
1 Volt to
10
Volts.
(50
ohms)
Control adjusts attenuation
to the high level
RF
input
for proper operating
level.
Fuse
holder
and
terminal
board
which
allows
setting
of
AC
input voltage
to
120
VAC
or
240
VAC
.
Connect
120
VAC
or
240
AVC
to
monitor.
Shows
the
RF
input -high
level preset frequency
(To
change
this
frequency, a
internal
crystal
must
be
replaced for high level
input only).
Allows
connection of the
composite signal
to
external
monitoring.
Provides composite output
to
drive a
model
730A
SCA
monitor.
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32.
33.
34.
35.
36.
37.
38.
39.
3.4
MAIN
CH.
DE-EMPHASIS
75us
DE-EMPH
Switch
RIGHT
AND
LEFT
output,
TB3
Composite
and
alann
outputs,
TB2
Remote
meter outputs,
TBl
EXT
COMPOSITE
IN
Jack
Composite
level Control
Composite
Select
Switch
Calibration
Provides composite output
which
has
been
passed
through a
75
s de-emphasis
network for external
monitoring.
Allows
the
75us
DE-EMPHASIS
circuit
to
be
switched into
the
LEFT
and
RIGHT
channel
demodulated output.
Provides demodulated
left
and
right
channel
information.
Provides a balanced
composite out signal
and
the
outputs for the optional
al
arm
circuits.
Provides
flasher
and
metering data for the
Model
804
Remote
Metering Panel.
Provides metering
capabilities
for monitoring
an
external composite signal
(
8Vpp}
Adjust
the
Level
of the
EXT
Composite
Input.
Select internal External
Composite
Signal to
be
applied to the metering
circuits.
Calibration
of
the meter
circuits
and
peak
detector
are the only
calibration
required for the
model
844.
-13-
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3.4.1 Meter
Calibration
Set
up:
1)
Meter
Cal
Button in
2)
De
Emph
Button out
3)
0db/100%
Buttonin
4) Total
Mod
Button in
Adjust Meter
Cal
Control
for
100%
or
0db
on
the
LEFT/TEST
meter.
3.4.2
3.5
Peak
Modulation Calibration
1)
Set Meter
Cal
Push
ButtonSwitch
to
the
in
position.
2)
Set%
peak
to 100.
3)
Set
peak
duration
to
0.
4) Adjust
Peak
Cal
Control
until
11
+
11
and
11
-
11
lightsare
on
and
peaks/min is in the constant
count
mode.
5)
Set%
peak
to
101
.
6) Press the
PEAKS/MIN
RESET
Switch.
7)
If
11
-
11
and
11
+
11
lights
are
on
and
PEAKS/MIN
is
in the constant count
mode,
readjust
PEAK
CAL
until
light
go
out
and
counter stops counting.
(A
delay of 2
sec.
may
be
encountered. )
8)
Repeat
steps
2 through 7 as required.
Measurements
Set
thumbwheel
switches to desired frequency
and
set
the
11
-
11
or
11
+"
push
button in
as
required.
3.5.1
Main
Channel
Modulation
(L+R)
Press the
L+R
function switch
and
the
odb/100%
attenuation
switch.
The
LEFT/TEST
meter will
indicate
the
main
channel
modulation
directly
in percent. A
fully
modulated
right
or
left
channel only signal will
indicate
45%
on
the meter. A
fully
modulated
L=R
signal will indicate
90%
and
a
fully
modulated
L=-R
signal will
indicate
0.
3.5.2
Stereo Subchannel Modulation
Press the
L-R
function switch
and
the
odb/100%
attenuation
switch.
The
LEFT/TEST
meter
will
indicate
the
stereo
subchannel modulation
directly
in percent. A
fully
modulated
right
or
left
channel only will
indicate
45%
on
the
meter. A
fully
modulatd
L=-R
signal will
indicate
90%
and
a
fully
modulated modulation
L=R
signal wil 1
indicate
0.
-14-
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3.5.3
Pilot
Carrier
Modulation
Press the
19KHz
function switch
and
the
-20db/10%
attenuation
switch.
The
LEFT/TEST
meter will
indicate
the
pilot
modulation
level,
with
the
100%
mark
on
the meter denoting
10%
modulation. Correct
pilot
modulation level
is
between
8%
and
10%.
This measurement
can
be
made
in the presence of
program
modulation.
3.5.4
3.5.5
3.5.5.1
38
KHz
Subcarrier Suppression
a.
Apply
a modulating
between
5
KHz
and
15
KHz
to
the
left
channel
of
the
transmitter
under
test,
and
adjust
its
level
to
indicate
90%
on
the
LEFT/TEST
meter.
b.
Press
the
38
KHz
function switch.
c.
With
the
meter
attenuation
switches,
select
an
attenuation
that
provides a usable reading
on
the
LEFT/TEST
meter.
The
38
KHz
subcarrier
suppression
is
then the algebraic
sum
of
the
meter reading
and
the
attenuatin
inserted.
For example, a meter reading of -2
dB
with the
-50
dB
meter attenuation switch depressed
denotes a
38
KHz
subcarrier
suppression of
52
dB
below
100%
modulation.
Stereo Separation
Stereo
Channel
Separation (Left
Channel
Modulated)
a.
Apply
a modulating signal
between
50
Hz
and
15
KHz
to
the
left
channel of the
transmitte
under
test
and
adjust
its
level
to
indicate
90%
on
the
LEFT
TEST
meter.
b. Press the R function switch.
c.
With
the
meter attenuation switches,
select
an
attenuation
that
provides a usable reading
on
the
LEFT/TEST
meter.
d.
The
channel separation
is
the algebraic
sum
of
the
meter reading
and
the attenuation
inserted,
less
approximately 1
dB
(0.915
dB)
to
account for the
90%
left-channel modulation
level.
For
example, a meter reading of -2
dB
with the
1%/-40
dB
meter
attenuation
switch
depressed denotes
a
stereo
channel separation
of
41
dB.
-
15-
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3.5.5.2
3.5.6
3.5.7
Stereo
Channel
Separation (Right
Channel
Modulated)
a.
Press the R function switch.
b. Press the
100%/0
dB
meter attenuation switch.
c.
Apply
a modulating signal
between
50
Hz
and
15
KHz
to
the
right
channel of the
transmitter
under
test
and
adjust
its
level
to
indicate
90%
on
the
LEFT/TEST
meter.
d. Press the L function switch.
e.
With
the
meter attenuation switches,
select
an
attenuation
that
provides a usable reading
on
the
LEFT/TEST
meter.
f.
The
channel separation
is
the algebraic
sum
of
the
meter reading
and
the
attenuation
inserted,
less
1
dB
to
account for the
90%
right-channel modulation
level.
Main
Channel
to
Subchannel Crosstalk
a. Press the
L+R
function switch
and
the
100%/0
dB
meter attenuation switch.
b.
Apply
an
L+R
modulating signal
to
the
transmitter
under
test
and
adjust
the
level
for
a
90%
reading
on
the
LEFT/TEST
meter.
c. Press
the
L-R
function switch.
d.
With
the meter attenuation switches,
select
an
attenuation
that
provides a usable reading
on
the
LEFT/TEST
meter.
e.
The
crosstalk
measure
is
the algebraic
sum
of
the
selected
attenuation
and
the meter
reading,
less
1
dB
to
account for the
90%
modulation
setting.
Subchannel to
Main
Channel
Crosstalk
a. Press the
L-R
function switch
and
the
100%/0
dB
meter attenuation switch.
b.
Apply
an
L-R
modulating signal to the
transmitter
under
test
and
adjust the level
for
90%
reading
on
the
LEFT/TEST
meter.
c. Press
the
L+R
function switch.
-16-
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3.5.8
3.5.9
3.5.10
d.
With
the meter
attenuation
switches,
select
an
attenuation
that
provides a usable reading
on
the
LEFT/TEST
meter.
e.
The
crosstalk
measured
is
the algebraic
sum
of
the
selected
attenuation
and
the meter
reading,
less
1
dB
to
account
for
the
90%
modulation
setting.
FM
Noise
a.
Apply
L+R
Modulating signal
of
the
transmitter
under
test
and
adjust
the
level
for
a
90%
reading
on
the
LEFT/TEST
meter.
b.
Turn
off
all
transmitter
modulation.
c.
Press
total
modulation switch.
d.
With
the
meter
attenuation
switches,
select
an
attenuation
that
provides a usable reading
on
the
LEFT/TEST
meter.
e.
The
algebraic
sum
of
the
selected
attenuation
and
the meter reading
is
the
FM
signal
to
noise
ratio.
----NOTE----
IF
A
DE-EMPHASIZED
READING
IS
REQUIRED,
THE
DE-EMPH
FUNCTION
SWITCH
MUST
BE
DEPRESSED.
Distortion
a.
Apply
a modulating signal
to
the
transmitter
channel
to
be
measured.
b. Connect a
distortion
analyzer
to
the
appropriate
rear
panel connector.
RIGHT
channel connector J4,
LEFT
channel connector
JS,
if
de-emphasis
is
desired;
or
RIGHT
channel connector J6,
LEFT
channel connector
J7,
if
de-emphasis
is
not
required.
Pilot
Frequency
a. Connect frequency counter
to
the
"FREQ.
COUNTER"
jack
on
the
monitor
front
panel.
b. Place the frequency
selector
switch
to
the
19.0
KHz
position
.
The
transmitted
pilot
frequency
is
counted
directly
on
the counter.
-17-
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3.5.11
Peak
Modulation
Peak
modulation
is
directly
read
on
the
peak
light
circuit.
Peak
modulation
can
be
determined
by
adjusting the
thumbwheel
switches
so
that
lights
and
counter
just
come
on
.
3.5.12
3.5.13
Incidental
and
Residual
AM
a. Applysignal of
transmitters
under
test
to
the
RF
INPUT
HI
LEVEL
jack.
b. Adjust
HI
LEVEL
INPUT
SET
until
the
SET
LED
ON
lamp
lights.
c.
Depress
AM
NOISE
function switch.
d.
With
the meter attenuator switches
select
an
attenuation
that
provides a usable reading
on
the
LEFT/TEST
meter.
e.
The
algebraic
sum
of
the selected attenuation
and
the meter readin9
is
the
AM
noise
level.
----NOTE----
THE
AM
NOISE
CAN
BE
READ
FRQ\1
THE
HIGH
LEVEL
RF
INPUT
ONLY.
Multipath
Noise
a. Depress the
MULTIPATH
function switch.
b.
With
the meter attenuation switches
select
an
attenuation
that
provides a usable reading
on
the
LEFT/TEST
meter.
c.
The
algebraic
sum
of the selected attenuation
and
the meter reading
is
the multipath noise
1
eve
1• ----NOTE----
MULTIPATH
NOISE
CAN
BE
READ
FROM
THE
LOW
LEVEL
RF
INPUT
ONLY.
-18-
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3.6
Absence
of Modulation
Alarm
(Optional)
The
alarm
is
triggered
when
the composite signal drops
below
30
percent
modulation for a period
of
time between 2 seconds
and
30
seconds.
Time
is
a user adjustment.
The
output supplied
is
an
open
collector
circuit
that
supplies a
ground
when
alarm
is
present. Output
is
available
on
rear
panel terminal board.
3.7 Carrier Fail
Alarm
(Optional}
The
alarm
is
triggered
when
the
RF
carrier
drops
below
250
V.
The
output supplied
is
an
open
collector
circuit
that
supplies a ground
when
the alarm
is
present. Output
is
available
on
TB2
on
the
rear
panel.
3.8
Use
of
Remote
Metering Panel.
Model
804
The
cable supplied with the
Remote
Metering Panel
is
connected to a
Terminal
Board
on
the monitor
rear
panel
and
will duplicate the
flasher
and
meter reading appearing
on
the monitor.
-19-
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