TFT 723 User manual
www.SteamPoweredRadio.Com
•
TO:
FROM:
DATE:
MODEL
723/734
FM
MONITOR USERS
TFT
16
September
1974
We
are
pleased
to
enclose
the
final
version
of
the
Instruction
Manual for
your
monitor.
Older
manuals
and
supplements
have
been
replaced
by
the
new
manual.
If
you
have
any
questions
or
if
you
would
like
to
let
us
know how
your
monitor
is
performing,
don't
hesitate
to
call
or
write
TFT
.
09164rd
3000
Olcott
Srreet, Santa Clara, California 9
50
5 1 (
408
} 2
46
-6
365
www.SteamPoweredRadio.Com
I
••
TABLE
OF
CONTENTS
I
Section
1
General
Information
I 1. 1
1.
2
1.3
General
Description
- - - - - - - - - -
1-1
Specifications
- - - - - - - - - -
1-2
Accessory
Equipment-
- - - -
1-4
I
1.4
1.5
Warranty
----------
1-5
Claim
for
Damage
in
Shipment-
1-5
I
Section
2
Installation
2
.1
Unpacking
and
Inspection
- - - - - - - -
2-1
I
2.2
2.3
2.4
Power
Requirements
----------
2-1
Installation
Remote
from
Transmitter
- -
2-1
Installation
at
Transmitter
Site
- - - - -
2-1
I
2.5
2.6
2.7
Model
724
Stereo
Monitor
Connection
- - -
2-2
Model 730 SCA
Monitor
Connection
- - - -
2-2
Model
704
Remote
Readout
Panel
Connection
(Optional)- - - - - - - - - - - - - - - -
2-2
ll
2.8
2.9
2.10
Automatic
Logging
Connection
(Optional) - -
2-2
Off-Frequency
Alarm
Connection
(Optional)-
2-3
Carrier-Off
Alarm
Connection
- - - - - - -
2-3
te
2.11
Section
3
Modulation
Alarm
Connection
(Optional) - - - -
2-3
Operation
I
3.1
3.2
General
- - - - - - - - - - - - - - - -
3-1
Controls,
Connectors,
and
Indicators
- - -
3-1
3.3
Turn-On
and
Warm-Up
- - - - - - - - -
3-7
'
3.4
3.5
Calibration
of
Modulation
Meter
and
Peak
Flashers
-------------
3-7
Measurement
of
Frequency
Modulation
I
3.6
Using
the
Modulation
Meter
-------
3-7
Measurement
of
Frequency
Modulation Using
the
Peak
Flashers
- - - - - - - - - - -
3-7
3
.7
I 3. 8
Main
Carrier
Frequency
Error
Measurements
---------------
3-7
Stereo
Pilot
Carrier
Frequency
Measurement
-------------
3-8
I
3.9
3
.10
SCA
Subcarrier
Frequency
Measurement
-
3-8
Use
of
the
Model 723
as
a
General
Purpose
Counter
- - - - - - - - - - - - - -
3-8
I
3.11
3.12
Audio Output - - - - - - - - - - - - - -
3-8
Operation
of
Model 723
from
External
5MHz
Time
Base-
- - - - - - - - - - -
3-8
3.13
Carrier-Off
Alarm
-----------
3-9
1
••
I i
www.SteamPoweredRadio.Com
'
3.14
Carrier
Off-Frequency
Alarm
(Optional) 3-9
••
3.
15
Model
704
Remote
Reado
ut
Panel
3-
9
3.16
Automatic
Logging
Outp
ut (Optional)
3-9
3.17
Measurement
of
Amplitude
Modulation
3-
10
I
Section
4
Theory
of
Operation
I
4.1
General
Block
Diagram
Disc
u
ssion
4-1
4.2
Crystal
Oscillator
(AS)
4-3
4.3
Fixed
Frequency
Board
(Al)
4-3
4.4
Local
Oscillator
Generator
(A2)
4-4
I
4.5
IF
Board
(A3) 4-4
4.6
Discriminator
Board
(A4)
4-5
4.7
Meter
Amp
and
Peak
Flasher
Board
(AS) 4-6
I
4.8
Channel
Filter
4-6
4.9
Power
Supply (A6)
4-6
4.10
Counter
and
Display
Board
4-7
4.11
Digital
to
Analog
Converter
(A9) (optional)
4-8
I
4.12
Carrier
Frequency
Alarm
(All)
(optional) 4-8
4.13
BCD
Automatic
Logging (optional) 4-9
4.14
Modulation
Alarm
(Al0) (optional)
4-9
I
Section
5
Maintenance
5.1
General
5-1
I
5.2
Access
5-1
5.3
Periodic
Maintenance
5-1
5.4
Master
Oscillator
Calibration
5-1
5.5
Calibration
of
the
Modulation
Meter
5-2
,_
5. 6
Calibration
of
the
Peak
Flashers
5-3
5.7
Adjustment
of
the
Internal
Calibration
Circuits
5-3
I
Section
6
Schematic
Diagrams
6.1
General
Block
Diagram
I
6.2
Front
Panel
and
Main
Chassis
Wiring
Diagram
6.3
Rear
Panel
Wiring
Diagram
6.4
Fixed
Frequency
Board
(Al)
6.5
L.
0.
Board
(A2)
1
6.6
IF
Board
(A3)
6.7
Discriminator
Board
(A4)
6.8
Audio
Amp
and
Peak
Flasher
Board
(AS)
I
6.9
Power
Supply
Board
(A6)
6.10
Counter
and
Display
Board
(A
7)
6.11
Crystal
Oscillator
(AS)
I
6.12
D/ A
Converter
(A9) (optional)
6.13
Modulation
Alarm
(Al0) (optional)
6.14
Model 704B
Remote
Panel
(optional)
I
1
••
ii
I
www.SteamPoweredRadio.Com
I
••
I
I
I
I
I
I
I
le
I
I
I
1·
I
I
I
--
1
I
1.1
General
Description
SECTION 1
GENERAL INFORMATION
The
Model
723
FM
Frequency
and
Modulation
Monitor
is
designed
for
continuous
monitoring
of
an
FM
broadcast
transmitter
operating
in
the
frequency
range
of
88 to 108 MHz.
The
monitor
is
factory-adjusted
for
the
cu
stomer's
assigned
transmitter
frequency
and
provides
digital
display
of
the
carrier
frequency
error*
as
well
as
quasi-peak
reading
meter
indication
of
total
modulation
percentage.
The
Model 723
can
be
used
with a
rooftop
antenna
for
off-the-air
monitoring,
or
it
can
be
connected
to the
transmitter
thro
ugh
an
attenuator
(furnished)
for
operation
at
the
transmitter
site
.
The
six-digit
frequency
display
on
the Model
723
can
also
be
used
as
a
10
MHz
general
purpose
counter
with
10
Hz
or
1 Hz
resolution.
Conversion
is
made
by
depressing
a
single
front-panel
pushbutton.
Other
features
of
the Model
723
include:
Frequency
stability
of
±100 Hz
per
year
Two
:flashers
that
indicate
when
modulation
peaks
exceed
a
preset
value
in
either
the
positive
or
negative
direction
Built-in
calibrator
for
modulation
indicators
Carrier-off
alarm
Outputs
for
remote
modulation
monitoring
IF
outputs
for
the
TFT
Model
724
Stereo
Monitor
and
the
TFT
Model 730 SCA
Monitor
Optional
analog
or
BCD
output
for
automatic
logging
of
carrier
frequency
error
Optional output
for
off-frequency
alarm
Provision
for
reading
pilot
and
SCA
carrier
frequencies
with
addition
of
Model
724
or
730
Residual
Amplitude Modulation
Measurement
at
the
Hi
level
R.
F.
input.
The
Model
723
complies
with
all
FCC
regulations
relating
to
FM
broadcast
monitors,
including
Section
73
. 331
pertaining
to FM
frequency
monitors
and
Section
73.
332,
Subsections
a,
b,
and
c,
pertaining
to
FM
modulation
monitors
.
*
Readout
indicates
frequency
error
and
not
the
carrier
frequency
itself.
1-1
www.SteamPoweredRadio.Com
In
addition,
the
Model 723,
when
used
with
the
Model
724
Stereo
Monitor,
meets
the
requirements
of
Section
73.332,
Subsections
d
and
e,
for
stereo
monitors;
and,
when
used
with
the
Model
730 SCA
Monitor,
meets
the
requirements
of
Section
73.332,
Subsections
f
and
g,
for
SCA
monitors.
1.2
Specifications
RF
Input
Frequency
range
- - - - - - - - - - - -
Sensitivity
- - - - - - - - - - - - - - -
Input
Level:
Low-level
input
- - - - - - - - - -
Hi-level
input
- - - - - - - - - - -
Selectivity:
3 dB bandwidth - - - - - - - - - -
40 dB bandwidth - - - - - - - - -
Input
impedance
-------------
Input
connector
-------------
Image
rejection
- - - - - - - - - - - - -
Signal
-
to-noise
ratio
----------
Carrier
level
meter
- - - - - - -
--
- -
Carrier
Frequency
Error
Measurement
Digital
readout
- - - - - - - - - - - - -
Accuracy
- - - - - - - - - - - - - - - -
Internal
frequency
standard
------
1-2
88
to
108
MHz
Approximately
250 µV, 60 dB
automatic
gain
control
range
250
µV
to
250 mV (75
ohms)
1V
to
10 V (50
ohms)
375
kHz
800 kHz
75
ohms
(nominal)
60 dB
70
dB
below
100%
modulation
at
400 Hz with 75
µs
de-emphasis
and 500 µV
input.
Front
panel
meter
to
indicate
relative
signal
level
Zero
to
± 10 kHz
in
1 Hz
increments
from
assigned
center
frequency
±100 Hz
per
year
Uses
a
precision
5 MHz
crystal
oscillator
in
a
proportionally
con-
trolled
oven.
A 1 MHz
output
is
provided
on
the
front
panel
for
calibration
against
WWVB
or
a
precision
frequency
source
.
I
••
I
I
I
I
I
I
I
el
I
I
I
I
I
I
I
••
I
www.SteamPoweredRadio.Com
I
••
I
I
I
I
I
I
I
le
I
I
I
I
I
I
I
••
I
Off-frequency
alarm
- - - - - - - -
Automatic
logging
output
- - - - - -
Modulation
Meter
Meter
range
- - - - - - - - - - -
Accuracy
- - - - - - - - - - - -
Frequency
response
- - - - - - -
Meter
characteristics
- - - - - -
Remote
metering
- - - - - - - -
Peak
Modulation
Indicators
Variable
peak
indicator
- - - - - -
Accuracy
- - - - - - - - - - -
Response
time
- - - - - - - - -
Modulation
Calibrator
Available
as
an
option to
provide
contact
closure.
Can
be
wired
for
desired
frequency
limits.
Available
as
an
option. BCD
output
or
a
:1::1
Vdc
output
representing
:1::l
kHz
of
carrier
frequency
error.
0 to
:1::133%
on
positive
or
negative
peaks.
(±100%
=
±75
kHz
FM
deviation)
±4%
over
entire
scale.
O.
5
dB
from
50 Hz
to
75 kHz
Peak-reading
circuit,
scale
,
and
ballistics
conform
to FCC
requirements.
Output
provided
for
Model 704B
Remote
Readout
Panel.
Level
set
by
a
front-panel
3-dtgtt
thumbwheel
switch
in
1%
steps
from
50%
to 129% on
positive
and
negative
peaks.
100%
setting
corresponds
to
an
FM
deviation
of
±75 kHz.
±4%
20
µs
pulse
Built-in
modulation
calibrator
for
calibration
of
the
modulation
meter
and
peak
flashers
from
the
front
panel.
Six-Digit
Frequency
Counter
Frequency
range
- - - - - - - - -
Input
sensitivity
- - - - - - - - -
1-3
10
Hz to
10
MHz
200 mV to 2 V
rms
www.SteamPoweredRadio.Com
Input
impedance
----------
Resolution
- - - - - - - - - - - - -
Display
accuracy
- - - - - - - - - -
Time-base
aging
rate
- - - - - - - -
Rear-Panel
O
utpu
ts
700 kHz
ou
tput
------------
Standard
Frequency
- - - - - - - - -
Remote
meter
and
peak
fl
asher
- - -
Audio
outputs
- - - - - - - - - - - - -
Amplitude
Modulation
Measurements
Range - - - - - - - - - - - - - - - - -
Frequency
Response
- - - - - - - - -
Signal
-
To
-
Noise
Ratio
--------
Physical
and
Environme
nt
Specifications
Power
required
------------
Operating
temperat
u
re
- - - - - - - -
Dim
ensi
ons
- - - - - - - - - - - - - -
Weight
- - - - - - - - - - - - - - - - -
c~~et
-----------------
1. 3
Accessory
Equipme
nt
1.
3.1
Accessories
Furnished
Instruction
Manual
1-
4
500
kilohms
sh
un
ted
by
25
pF
1 Hz
or
10
Hz,
front-panel
switchab
le
±1
count
- 8
1 x 10
/day
after
30
days
of
op
eratio
n
Output
to
drive
TFT
Model 724
Stereo
Monitor
1
kHz,
TTL
level
For
use
with
Model 704B
remote
readout
panel.
Two
outputs
are
provided,
one
with
de-emphasis
and one
without
Residual
AM
measurements
up
to
20%
can
be
made
on
the
R F
signal
at
the
high
l
eve
l
input.
75µsec
de-emphasis
network
is
incorporated
in
this
output
.
70dB
below
100% with
75µsec
de-emphasis
11
5/230
V,
50 to 400 H
z,
30
watts
maximum
0°
to
+50°C
1
9"w
x
7"h
x
16"d
17
pounds
Rack
mo
unt
ed
I
••
I
I
I
I
I
I
I
el
I
I
I
I
I
I
••
I
www.SteamPoweredRadio.Com
I
••
I
I
I
I
I
I
I
I
I
I
I
I
I
••
I
1.
3. 2
Accessories
Available
Model 704B
Remote
Readout
Panel
.
Duplicates
meter
and
peak-flasher
readings
of
the
Model 723.
Model 724
Stereo
Monitor
.
For
use
by
stereo
FM
stations
to
meet
all
FCC
stereo
monitoring
requirements
.
Model 730 SCA
Monitor
.
Enables
FM
stations
broadcasting
SCA
informa-
tion
on
the
carrier
to
meet
all
FCC
SCA
monitoring
requirements
.
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
partf
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
ex-
pressly
agreed
that
replacement
and
repair
shall
be
the
sole
remedy
of
BUYER
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
BUYER.
This
warranty
does
not
apply
to
instruments
which,
in
the
opinion
of
the
SELLER,
have
been
altered
or
misused.
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
.
1-5
www.SteamPoweredRadio.Com
WE SI:N'CERELY
PLEDGE
OUR IMMEDIATE AND
FULLEST
COOPERATION
TO
ALL
USERS
OF
OUR
PRECISION
ELECTRONIC
I:N'STRUMENTS.
PLEASE
ADVISE US
IF
WE CAN ASSIST YOU IN' ANY MANNER
Time
&
Frequency
Technology,
Inc.
3000
Olcott
Street
Santa
Clara,
California
95051
408-246-6365
1-6
•
I
••
I
I
I
I
I
I
I
el
I
I
I
I
I
I
I
••
I
www.SteamPoweredRadio.Com
I
••
I
I
I
I
I
I
I
I
I
I
I
I
I
1•
1
2.1
SECTION 2
INSTALLATION
Unpacking
and
Inspection.
Upon
receiving
the
instrument,
inspect
the
packing
box
and
instru1j11ent
for
signs
of
possible
shipping
damage.
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 cl
aim
with
the
transportation
company,
or
with
the in
surance
company
if
insured
separately.
2.2
Power
Requir
e
ments
.
The
Model 723
is
factory
wired
to
operate
from
either
a
115-volt
or
a
230-volt
ac
source.
A
marking
on
the
rear
panel
of
the
instrument
indicates
which
voltage
is
to
be
used
.
Th
e
line
freq
u
ency
must
be
between
50
and
400 Hz.
Maximum
power
required
is
30
watts.
2.
3
Instal
l
ation
Remote
from
Transmitter.
When the
instrument
is
installed
in
the
studio,
or
any pl
ace
distant
from
the
transmitter,
a
rooftop
antenna
must
be
used.
Any conventional FM
or
television
antenna
is
satisfactory
for
this
purpose.
A 75-
ohm
coaxial
cable
should
be
used
to
feed
the
signal
from
the
antenna
to
the
RF
INPUT
connector
on
the
rear
panel
of
the Model 723.
The
procedure
for
proper
adjustment
of
the
input
le
v
el
is
as
follows:
a.
b.
Depress
the PWR
and
MA
IN CARR
switches
on
the
Model 723
front
panel
.
Rotate
the
antenna
for
maximum
reading
on
the CARRIER
LEVEL
meter.
The
meter
reading
must
be
in
the
green
region
for
proper
Monitor
operation
.
If
the
meter
reading
is
above
the
green
region,
ins
e
rt
the 40 dB
attenuator
in
the
RF
input.
The
monitor
is
now
ready
for
use.
2.
4
Installation
at
Transmitter
Site
When
th
e
instrument
is
installed
at
the
transmitter
site,
connect
the
modulated
R.
F.
sampling
point
on
the
transmitter
to
the
HIGH
LEVEL
INPUT
on
the
rear
panel
using
a 50-
ohm
coaxial
cable.
The
voltage
at
this
point
must
not
exceed
10
V
rms.
CAUTION
DO
NOT CONNECT THE
LOW-LEVEL
INPUT TO THE TRANSMITTER
R.
F.
SAMPLING POINT.
2-1
www.SteamPoweredRadio.Com
Install
a
one-quarter
inch
wide
braided
ground
wire
from
the
Model 723
chassis
to
the
transmitter
ground
bus.
The
procedure
for
proper
adjustment
of
input
level
to
the
Model 723
is
as
follows:
a.
Depress
the
PWR
and
MAIN CARR
switches
on
the
Model
723
front
panel.
b.
Adjust
coupling
of
the
RF
signal
from
the
transmitter
for
a
CARRIER
LEVEL
meter
reading
in
the
green
region.
The
Monitor
is
now
ready
for
use.
2. 5
2.6
Model 724
Stereo
Monitor
Connection
o
When a Model 724
is
to
be
used
with
the
Model
723,
proceed
as
follows:
a.
b.
c.
d.
Connect
a 5
wire
cable
from
J13
on
the
rear
panel
of
the
Model
723
to
the
power
input
terminal
strip
on
the
Model
724,
also
a
#18 AWG
or
larger
wire
between
the
two
chassis.
Connect
a
coaxial
cable
from
JlO
or
Jll
on
the
rear
panel
of
the
Model 723
to
the
700
kHz
INPUT
connector
on
the
Model 724.
Connect
a
coaxial
cable
from
the
PILOT
CARRIER
OUTPUT
(.-i
1)
connector
of
the
Model 724
to
PILOT
CARRIER
connector
J6
on
the
rear
panel
of
the
Model
7230
Refer
to
the
Model 724
manual
for
calibration
instructions.
Model 730 SCA
Monitor
Connection.
When a
Model
730
is
to
be
used
with
the
Model
723,
proceed
as
follows:
a.
Connect
a
coaxial
cable
from
J2
on
the
rear
panel
of
the
Model
723
to
the
composite
input
connector
on
the
Model 730.
b.
Connect
a
coaxial
cable
from
the
SCA CARRIER
OUTPUT
connector
on
the
Model
730
to
SCA CARR
connector
J5
on
the
Model 723.
c.
Refer
to
the
Model 730
manual
for
calibration
instructions
.
2.7
Model
704B
Remote
Readout
Panel
Connection
(Optional).
When a Model 704B
is
to
be
used
with
the
Model 723,
connect
the
5-
wire
cable
of
the
Model 704
to
terminals
A,
C,
F,
G,
and
H
of
J12
on
the
rear
pane
l
of
the
Model 723.
2.
8
Automatic
Logging
Connection
(Optional).
Two
automatic
logging
options
are
available
--
one
providing
a BCD
out-
put
and
the
other
providing
an
analog
output
.
For
the
BCD
option,
rear
panel
2-2
I
••
I
I
I
I
I
I
I
el
I
I
I
I
I
I
I
••
I
www.SteamPoweredRadio.Com
I
••
I
I
I
I
I
I
I
I
I
I
I
I
I
••
I
connector
J14
on
the Model 723
will
be
a
50-pin
connector.
For
the
analog
option,
J14
will
be
a
pair
of
banana
jacks.
In
either
case,
an
appropriat.e
cable
must
be
connected
between
Jl4
on the re
ar
panel
of
the Model 723
and
the input
connector(s)
on
the logging
equipment.
Refer
to
the
Rear
Panel
Wiring
Diagram,
Figure
6-3,
for
J14
pin
connections.
2.9
Off-
Frequency
Alarm
Connection (Optional).
If
an
off-frequency
alarm
is
to
be
used
with
the Model 723,
connect
terminals
Band
F
of
terminal
strip
J12
on the Model 723
rear
panel
to
the
appropriate
terminals
on the
alarm
device.
When
the
carrier
frequency
error
exc
e
eds
the
preset
v
alue,
terminal
B
of
J12
shorts
to
ground
(terminal
F).
Maximum
power-handling
capability
is
0. 5
amperes
at
50
v
olts.
2.10
Carrier
-Off
Alarm
Connection.
Connect
the ext.ernal
alarm
de
v
ice
to
banana
jacks
J3
and
J4
on the Model 723
rear
panel.
These
jacks
are
shorted
together
when the
transmitter
carrier
goes
off
. Ne
ither
of
the
jacks
is
grounded
tn
the
Monitor
.
Maximum
power-handling
capability
is
0.
5
amperes
at
50
volts.
2.11
Modulation
Alarm
Connection
(Optional)
Connect
the
external
alarm
device
to
terminals
"D"
and
"E" of
J12
on
the Model 723
rear
panel.
These
terminals
are
short.ed
together
when
t.he
total
modulation
drops
below
10
%
for
a
period
of
time
which
can
be
adjusted
on
the
modulation
alarm
(Al0).
Neither
of
the
jacks
is
grounded
in
t.he
monitor.
Maximum
power-handling
capability
is
0.
5
amperes
at
50
volts.
2-3
www.SteamPoweredRadio.Com
I
••
I
I
I
I
I
I
I
I
I
I
I
1
I
••
I
3.
1
General.
SECTION 3
OPERATION
The
Model
723
FM
Frequency
and
Modulation
Monitor
displays
the
frequency
error
of
the
carrier
being
monitored.
*
It
also
displays
the
total
modulation
per
-
centage
and
provides
a
flashing
indication
when
either
the
positive
or
negative
modulation
peaks
exceed
the
percentage
set
on
the
front-panel
thumbwheel
switches
.
When
used
in
conjunction
with
the Model
724,
the
frequency
of
the
stereo
pilot
carrier
can
be
displayed;
and when
used
with
the
Model
730,
the
frequency
of
the
SCA
subcarrier
can
be
disp
l
ayed.
The
Model 723
can
also
be
used
as
a
general-
purpose
six-digit
counter.
3.
2
Controls
,
Connectors,
and
Indicators.
3.
2.1
Front
Panel.
Fig
.
3-1
Ref.
No.
1
2
3
Name
COUNTER INPUT/ 1 MHz OUPUT
connector
PWR
switch
10
Hz/ 1 Hz
switch
Function
In
the
General
Purpose
Counter
mode
,
provides
a
means
of
introd
u
cing
the
signal
to
be
co\lllted
(see
Ref
. No. 4 below).
In the
Monitor
mode
(see
Ref.
No. 7
below),
this
connector
delivers
a 1 MHz
output
from
the
internal
time
base,
for
calibrating
the
time
base.
When
depressed,
energizes
the
instrument.
NOTE:
The
crystal
oven
is
not
controlled
by
this
switch;
power
is
supplied
to
the
oven
circuit
whenever
the
instrument
is
plugged into a
power
source.
Used
in
the
Counter
and
Main
Carrier
modes
only. When
de-
pressed,
provides
1 Hz
resolu-
tion
of
the
freq
u
ency
count; when
in
the
out
position,
provides
10
Hz
resolution.
* Note
that
when
the
main
carrier
is
being
monitored,
the di
gital
display
indicates
the
frequency
error
rather
than the
carrier
frequency
.
3-
1
www.SteamPoweredRadio.Com
Fig.
3-1
Ref.
No.
4
5
6
7
8
9
10
11
12
13
Name
FREQ
CTR
switch,
COUNTER
lamp,
and
O.
F.
la.mp
SCA CARR
switch
and SCA
lamp
PILOT
CARR
switch
and
PILOT
lamp
MAIN CARR
switch
and
MAIN
CARR
lamp
METER
(-)
switch
METER
(+)
switch
METER
CAL
switch
FLASHER CAL
control
METER
CAL
control
Modulation
meter
3-2
I.
Function
I
The
FREQ
CTR
switch
Is
mechanically
• 1
connected
to
the
SCA CARR,
PILOT
CARR, and MAIN CARR
switches
so
that
when
one
is
pressed
the
others
are
out.
Depressing
the
FREQ
CTR
I
switch
puts
the
instrument
in
the
general-purpose
counter
mode
and
turns
on
the
COUNTER
lamp.
In
I
this
mode
only,
if
the
counter
ov
erflows,
the O.F.lamp
comes
on.
Used
with
Model 730 SCA
Monitor.
When
depressed,
connects
J5
to
input
of
counter
board
and
counts
frequency
present
at
J5.
Counter
reads
with
1 Hz
resolution.
De-
pressing
the
SCA CARR
switch
also
turns
on
the
SCA
lamp.
When
PILOT
CARR
switch
is
depressed,
it
turnc; on
PILOT
lamp
s.nd
connects
input
at
J6
into
counter
to
indicate
I
I
I
I
pilot
carrier
frequency.
Resolu-
tion
is
O.
1 Hz.
Used
with
Model 724
Stereo
Monitor.
When MAIN CARR
switch
is
de-
pressed,
it
places
the
Model 723 in
its
normal
mode
and
turns
on
the
MAIN CARR
lamp
.
Digital
display
indicates
main
carrier
frequency
error
.
Causes
meter
to
read
negative
modulation
peaks.
Causes
meter
to
read
positive
modulation
peaks.
When
depressed,
provides
an
internal
calibration
signal
for
the
modulation
meter
and
the
peak
flashers
(see
Section
3.4).
Used
in
calibrating
the
peak
flashers
(see
Section
3.
4)
.
Used
in
calibrating
the
modulation
meter
(see
Section
3.
4).
Reads
carrier
total
modulation
dir-
ectly
in
percentage.
The
modulation
being
monitored,
positive
or
negative,
depends
on
the
setting
of
the
(-) and
(+)
switches.
I
I
I
I
I
I
••
I
www.SteamPoweredRadio.Com
I
••
Fig.
3-1
Ref.
No.
Name
14
PEAK
MODULATION
switches
and
I
lamps
I
I
I
15
CARRIER
LEVEL
meter
I
16
"+"
and
"-"
lamps
I
I 17 GATE
lamp
,_
I 18
OVENlamp
I
I 19
Freque~cy
error
display
I
3.2.2
Rear
Panel.
I
Fig.
3-2
Ref.
No.
Name
I 1
RF
INPUT
connector
Jl
I
••
2 COMPOSITE
OUTPUT
connector
J2
I
3-3
Function
The
PEAK
MODULATION
switches
set
the
peak
modulation
percentage
at
which
the
lamps
will
flash.
The
PEAK
MODULATION
lamps
flash
when the
modulation
peaks
exceed
the
setting
of
the
PEAK
MODULATION
switches
--
the +
lamp
for
positive
modulation
peaks
and the -
lamp
for
negative
peaks.
A
meter
reading
in
the
green
region
indicates
that
the
RF
input
level
is
correct
for
proper
Monitor
operation.
"+"
lamp
indicates
that
the
carrier
frequency
is
above
its
assigned
frequency;
"-"
lamp
indicates
that
the
carrier
frequency
is
below
its
assigned
frequency.
Flashes
every
two
seconds
or
every
20
seconds
depending
upon
resolution
selected,
to
indicate
that
the
counter
gating
is
operating
properly,
and
that
frequency
sampling
is
taking
place.
Lighted
when
crystal
oven
is
operating.
Relative
brightness
of
OVEN
lamp
is
an
indication
of
the
amount
of
current
being
drawn
by
the
oven.
In
the
Main
Carrier
mode,
indicates
the
carrier
frequency
error
in
kHz.
In
other
modes,
indicates
frequency
being
counted.
Function
Provides
a
means
for
connecting
a
75-ohm
cab
le
from
a
rooftop
antenna
at
a
remote
site,
or
from
the
transmitter
RF
coupler
through
a
40-dB
pad
at
the
transmitter
site.
Maximum
input
is
1 V•
Delivers
the
recovered
composite
audio
signal.
Output
is
1 V
rms
.
for
±75 kHz
FM
deviation.
www.SteamPoweredRadio.Com
Fig
.
3-2
Ref.
No.
3
4
5
6
7
9
10
11
12
Name
CARRIER ALARM
connectors
J3
and
J4
PILOT
CARR
connector
J6
SCA CARR
connector
J5
5 MHz
INPUT
connector
J7
and
switch
Audio
output
IF
connector
J8
1 KHz
connector
J9
700
KHz
output
connectors
JlO
and
Jll
IA
SLO
BLO
fuse
115
V
AC
line
cord
POWER SUP'PLY
TO
MODEL 724
terminal
strip
J13
3-4
I
Function
Provides
connection
to
an
external
carrier-off
alarm
. A
relay
in
the
Monitor
shorts
together
the
two
con
·-
nectors
when
the
monitored
carrier
goes
off.
••
I
Provides
means
for
connecting
the
pilot
carrier
input
from
a Model 724
Stereo
Monitor
.
Provides
means
for
connecting
the
~CA.
carrier
input
from
a Model 730
SCA
Monitor.
Connector
provides
means
for
intro-
ducing
an
external
5 MHz
time-base
signal
(0
. 5 V
rms
or
greater).
Switch
must
be
in
EXT
position
when
using
external
time
base.
I
I
I
I
I
I
Delivers
the
recovered
audio
from
the
75 µ s
de-emphasis
network.
The
audio
level
is
1 V
rms
for
±75
kHz
deviation.
Delivers
a 1
kHz
signal
divided
down
from
the
5 MHz
time
base,
for
driv-
ing
external
devices
such
as
a
digital
clock
and
calendar
system.
TTL
level.
_,
I
I
This
is
the
700
kHz
second
IF
signal
used
to
drive
the Model 724
Stereo
Monitor.
The
level
should
be
l00mV
rms
into
50
ohms.
Fuses
the
ac
power
circuit.
For
connecting
the
Monitor
to
a
power
source.
If
the
Monitor
is
wired
for
a 230 V
input,
the
line
cord
will
be
so
marked.
l
Supplies
+15
V,
+
l0V,
-15V,
arid a
CAL
signal
to
the
Model 724 when
I
used.
I
I
I
I
I
••
I
www.SteamPoweredRadio.Com
I
'•
I
I
I
I
I
I
I
1e
I
I
I
I
I
I
I
••
I
Fig.
3-2
Ref.
No.
13
14
15
16
Name
AUTOMATIC LOGGING OUTPUT
connector
Jl4
Terminal
strip
Jl2
RF
LEVEL
HIGH
Connector
J16
AM
DETECTOR
OUTPUT
3-5
Function
If
this
option
is
ordered,
Jl4
will
be
a
50-pin
connector
providing
BCD
output
of
the
digital
display
or
a
pair
of
banana
plugs
providing
an
analog
output
of
the
carrier
frequency
error
(±1 Vdc
for
±1 lQfz
frequency
error),
as
specified
by
the
customer.
Pro
v
ides
the
following
outputs:
A:
The
same
voltage
that
operates
the
modulation
meter,
to
operate
the Model 704B
Remote
Readout
Panel.
Connect
704B
red
wire.
B:
Closes
a
circuit
to
ground
when
the
measured
carrier
frequency
error
exceeds
a
preset
limit,
for
operation
of
an
external
alarm.
Will
handle
a
load
of
O.
5 A
at
50
V.
Optional.
C:
The
same
voltage
that
operates
the
front-panel
+
PEAK
MODULATION
lamp,
for
operating
the
correspond-
ing
lamp
on the Model 704B
Remote
Readout
Panel.
Connect
the 704B
brown
wire.
F:
Ground.
Connect
704B
black
wir
e.
G:
Th
e
same
voltage
that
ope
ra
te
s
the
front-panel
-
PEAK
MODULATION
lamp,
for
operating
the
corresponding
lamp
on
the Model 704B
Remote
Readout
Panel.
Connect
the 704B
white
wire.
H: +5 Vdc.
Connect
704B
green
wire.
Provides
a
means
for
direct
connection
to
the
transmitter
RF
coupler
at
the
transmitter
site.
Input
range
is
1V
to
10 V.
Provides
a D. C.
output
propotional
to
the
R.
F.
input
level
at
the
High-Level
R.
F.
input,
and
an
A.
C.
voltage
propor-
tional
to the
A.
M.
on
the
carrier
at
the
High-Level
input.
www.SteamPoweredRadio.Com
I
••
I
I
I
I
I
I
I
le
I
I
I
11
I
I
I
••
FREQUENCY KHz
0
.0
0
--+-
CARRIEII
LEVEL
!TlE/tL
TIii£
AND
FREOUENCY
TECHNOLOClY,INC.
FM FREQUENCY AND MODULATION MONITOR MODEL
723
COUNTER JNPUT
(2VMAX)
f
MHz.
OUTPUT
----
COIJNTER------METER
IO
Hz
FREQ
SCA
PILOT MAIN
PWR
IHz
CTR CARR CARR
CARR
(-)
(+)
CAL
2 3 4 5 6 7 8 9
10
J14
AUTOMATIC
LO
_
GGING
OUTPUT
AUDIO
bUTPUT
1TH
DE~EMPHASIS
FLASHER
CAL
0
METER
CAL
e,e,0e,e,0
...J
~
0
~
g
s
~
~
+ ;
+
MODEL
723
RE
V I
S(O
NS
FIGL,f<E
3-1
i:-IGURE.
3-c
-r;:-r
KAL&
//I
~v•o
•Y
OATW
fl
.. / ~
•7
RSVIHD
PAGE
3-(o
This manual suits for next models
1
Table of contents
Other TFT Measuring Instrument manuals
Popular Measuring Instrument manuals by other brands
Texmate
Texmate FL-B101Q-HZ instruction manual
Arkray
Arkray SPOTCHEM EZ SP-4430 operating manual
PeakTech
PeakTech TK-60 Operation manual
ALGE-Timing
ALGE-Timing Timy SPEED manual
Tektronix
Tektronix KEITHLEY 4200A-SCS-PKB quick start guide
PCB Piezotronics
PCB Piezotronics M350D02 Installation and operating manual
