ELCOM INSTA-PEAK II User manual

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I •
TECHNICAL MANlW..
INSTA-PEAK II
DUAL SPECTRUM AUDIO PROCESSOR
M)DEL AP-50 FM
FOR FM RADIO AND TEI..EVISION
ELOJM SPECIALTY PRODUCTS, INC.
2810 REDDING _f.VENUE S'IE. E
SACRAMENTO, CALIFORNIA 95820
[phone]

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TABLE
OF
CONTENTS
SECTION
TITLE
1 INTRODUCTION
1.
1
GENERAL
"}
'
1.2
~ - FUNCTIONAL DESCRIPTION
1.
3 .,
1
·
PHY? I
CAL
DES
CR
I PT I
ON
1.4
.,i
,.
SERVICE
AND
REPAIR
PAGE
1-1
1-1
1-1
1-2
1-2
·.
'
..
·
1.
5 ·.:
WARRANTY
1-
~
1.6
SPECIFICATIONS
1--3
I I INSTALLATION
2-1
2.1
MECHANICAL INSTALLATION
2-1
2,2
ELECTRICAL CONSIDERATION
FOR
-
BROADCAST
USE
2-1
2.3
USE
OF
PRE-EMPHASIS
AND
DE-EMPHASIS
2-1
2,4
STEREO INTERCONNECTION
2-2
2.5
ELECTRICAL CONNECTIONS
2-2
I I I OPERATIONAL
SET-Uf
3-1
3,1
GENERAL
3-1
3.2
:
CONTROL
SETTINGS
3-1
3.
3
:,
· PROOF-OF-PERFORMANCE
MEASUREMENTS
3-2
IV
f,
THEORY
OF
OPERATION
4-1
4.
1
i~-
GENERAL
4-1
4.2
INPUT LEVEL CIRCUITRY
5-1
V
MAINTENANCE
AND
REPAIR
5-1
5.
1
GENERAL
/

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TABLE
OF
CONTENTS
(CONT.)
SECTION
TITLE
5.2
ACCESS
TO
INTERNAL
COMPONENTS
5.3
TROUBLE
SHOOTING
METHODS
5.4
CHECK
OF
BALANCE
CONTROL
SETTING
5.5
ADJUSTMENT
OF
GAIN
REDUCTION
METER
ZERO
PAGE
5-1
5-1
5-1
5-2

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LIST
OF
ILLUSTRATIONS
FIGURE
NO,
TITLE
2.1
AUDIO
ATTENUATOR
NETWORKS
4,1
FUNCTIONAL
BLOCK
DIAGRAM
,.
5.1
•i'
\·
I\
SCHEMATIC
DIAGRAM-MAIN
SECTION
I
t ,
'«t
i'
'
5.2
'I'{,
, /, .
.,
·'
)
r.'
SCHEMATIC
DIAGRAM-POWER
SUPPLY
5.3
1}
J
f'·
',
'if/,
TABLE
OF
TEST
POINT
VOLTAGES
5,4
•,•,,1~1
..-,
I
~OC~TION
OF
COMPONENTS
AND
TEST
..
,.::.
'·
.
.
..
POINTS
/
PAGE
2-0
4-0
s-o
5-3
,
5-4
5-5

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SECTION
I
INTRODUCTION
1,1
GENERAL
THIS
MANUAL
PROVIDES
INSTALLATION,
OPERATING
AND
MAINTENANCE
INSTRUCTIONS
FOR
THE
ELCOM
ENGINEERING
COMPANY,
MODEL
AP-50
FM
INSTA-PEAK
II
AUDIO
PROCESSOR.
'
,. .
THE
MODEL
AP-50
FM
IS
DESIGNED
FOR
USE
WITH
FM
BROADCAST
AND
TV
TRANSMITTERS
WHERE
PRECISE
CONTROL
OF
DYNAMIC
RANGE
AND
AUDIO
TRANSIENTS
IS
ESSENTIAL,
IT
ALLOWS
THE
FULL
USE
OF
TRANSMITTER
MODULATION
C~PABILITY
'.
WITHOUT
THE
RISK
OF
OVER-MODULATION,
CONT-
INUOUS
LEVEL
COMPRESSION
OF
20
DB
IS
ACHIEVABLE
WITHOUT
AUDIBLE
DISTORTION
$UCH
AS
LEV~L
PUMPING,
THIS
IS
MADE
POSSIBLE
BY
USE
OF
PASSIVE
OPTICAL
ATTENUATORS,
SPLIT
SP~CTRUM
AUDIO
DISTRIBUTION,
INTERNAL
PRE-EMPHASIS
AND
DE-EMPHASIS,
AND
SPECIAL
ANTI-RING
CIRCUITRY
WHICH
PREVENTS
OVER-MODULATION
CAUSED
BY
FREQUENCY
SELECTIVE
NETWORKS
WITHIN
MOST
STEREO
GENERATORS
ANO
EXCITERS.
1,2
FUNCTIONAL
DESCRIPTION
THE
UNIQUE
LEVEL
CONTROL
METHOD
TOGETHER
WI
TH
THE
"SPLIT-
SPECTRUM"
TECHNIQUE
PROVIDES
AUTOMATIC
LEVEL
AND
PEAK
CONTROL
WHICH
IS
IN-AUDIBLE
TO
THE
LISTNER
EVEN
WITH
HIGH
COMPRESSION
RATIO,
TESTS
INDICATE
THAT
IN
ORDER
TO
PREVENT
THE
AUDIBLE
PUMPING
EFFECTS
Of
ORDINARY
LEVEL
CONTROL
SYSTEMS
THE
AUDIO
SPECTRUM
CAN
BE
SP~IT
INTO
TWO
SEGMENTS,
APPROXIMATELY
10
TO
700
HZ
AND
100
TO
15
1
000
HZ,
EACH
OPERATING
WITH
SEPERATE
LEVEL
CONTROL,
DIVIDING
THE
SPEC~RUM
INTO
MORE
SEGMENTS
INCREASES
THE
EQUIPMENT
COMPLEXITY
/
AND
ADDS
NOTHING
TO
THE
PERFORMANCE,
THIS
SPLITTING
TECHNIQUE
HAS
BEEN
KNOWN
FOR
20
OR
30
YEARS,
BUT
HAS
NOT
BEEN
WIDELY
USED
·
1-1

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UNTIL RECENTLY, THE SPLIT SPECTRUM TECHNIQUE IS COMBINED WITH
A LEVEL CONTROL SYSTEM UTILIZING PHOTO CONDUCTIVE CELLS AS
AUTOMATIC VARIABLE ATTENUATORS FOR SMOOTH DISTORTIONLESS OPERATION,
THE INITIAL RESPONSE DELAY OF THE Ar TENUATOR TO A SUDDEN AUDIO
INPUT MAY BE SEVERAL MILLISECONDS, SO TO PREVENT THE PASSAGE OF
SUCH A PEAK THROUGH THE SYSTEM A PAIR OF LIGHT EMITTING DIODES CLAMP
THE LEVEL FOR A FEW CYCLES UNTIL THE ATTENUATOR CELLS CAN RESPOND
AND TAKE CONTROL, MOST FM STEREO GENERATORS AND EXCITERS EXHIBIT
AUDIO ' 0VER-SHOOT AND RINGING WHEN SUBJECTED TO FAST RISE AND FALL
OF THE AUDIO WAVE FORM SUCH AS CAN BE CAUSED BY THE HARD LIMITING
NECESSARY FOR TIGHT CONTROL OF CEILING AMPLITUDE. THE ELCOM INSTA-
PEAK II USES A PROPRIETARY "ANTI-RING" . CIRCUIT TO PREVENT OVER-
SHOOT AND RINGING.
113 PHYSICAL DESCRIPTION
THE INSTA-PEAK II IS SELF-CONTAINED IN A WELL SHIELDED
MODULE DESIGNED TO MOUNT IN THE STANDARD ELCOM RACK MOUNTING
FRAME. THE INSTA-PEAK II MODULES CAN BE INSTALLED IN THE FRAME
FOR STEREO OPERATION.
WHEN A SINGLE INSTA-PEAK II IS USED THE ADJACENT MODULE
SPACE IS COVERED WITH A BLANK PANEL THAT IS SUPPLI E D, A DEPTH OF
12 INCHES BEHIND THE FRONT PANEL IS USED,
A FRONT PANEL METER AND SELECTOR SWITCH INDICATES INPUT
LEVEL, GAIN ~~DUCTION
1
IN DB, AND OUTPUT LEVEL.
1.4 SERVICE AND REPAIRS
. .
IF YOU HAVE DIFFICULTY IN OPERATING OR MAINTAINING YOUR
INSTA-PEAK II CALL YOUR LOCAL AUTHORIZED DJSTR{BUTOR FROM WHOM
YOU ORIGINALLY PURCHASED THE UNIT, OR CALL ELCOM ENGINEERING
COMPANY IN SANTA ANA, CALIFORNIA,
1-2

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1,5
WARRANTY
A
STANDARD
ELCOM
WARRANTY
CARD
HAS
BEEN
INCLUDED
WITH
YOUR
INSTA-PEAK
II.
TO
VALIDATE
YOUR
WARRANTY,
COMPLETE
AND
RETURN
THE
POSTCARD
SECTION
TO
ELCOM
AS
SOON
AS
POSSIBLE.
1,6
SPECIFICATIONS
INPUT
IMPEDANCE:
600
OHMS,
BALANCED
OR
UNBALANCED.
OUT~UJ
LOAD
·
IMPEDANCE:
600
OHMS
NOMINAL
LOAD,
TRANSFORMER
ISOLATED.
OUTPUT
SOURCE
IMPEDANCE:125
OHMS.
OUTPUT
LEVEL
(MAX.):
INPUT
LEVEL:
FREQUENCY
RESPONSE:
HARMONIC
DISTORTION:
ATTACK
TIME:
RECOVERY
TIME:
SIGNAL
TO
NOISE
RATIO:
POWER
~
~EQU~R~M&Nt$:
DIMENSIONS
(WITH
MO~N
lt~
~
FRAME):
20
DBM.
-50
DBM
TO
+10
DBM.
±1
DB
50-15,000
HZ
WITH
OR
WITHOUT
GAIN
REOUCTI
ON.
-
LESS
THAN
1\
WITH
OR
WITHOUT
GAIN
REDUCTION
AND
+20
DBM
OUTPUT.
INSTANTANEOUS.
0.5
TO
2
SECONDS
DEPENDING
ON
PREVIOUS
GAIN
REDUCTION.
GREATER
THAN
65
DB.
6
WATTS
100~130
VOLTS
50/60
HZ.
3
1/2
I
NCHES
HIGH,
19
INCHES
WIDE
AND
12
INCHES
DEEP.
/
1-3

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600 OHM
INPUT ··
... \ tr;;; '
'.:.• .. "·
r)R I fl,,
10 (
11)
15
'
20
24
30
.
•
Rl
~ l30
430
510
510
560
2-0
600 OHM
OUTPUT
Q?
360
220
120
75
39
AUDIO ATTENUATOR NETWORK
FIGURE 2-'l

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SECT
I
ON
II
INSTALLATION
211
MECHANICAL
INSTALLATION
THE
INSTA-PEAK
II
MODULES
ARE
SUPPLIED
IN
A 3
1/2
INCH
HIGH
,,~K
MOUNTING
FRAME.
THE
FRAME
WILL
HOLD
TWO
MODULES
OR
ONE
Mi9,ULE
~ITH
A
BLANK
PANEL.
THE
MODULES
ARE
EASILY
REMOVED
BY
M~~~S
OF
TWO
THUMB
SCREWS.
THE
MODULES
REQUIRE
12
INCHES
OF
DEPT~
_
BEHINO
THE
FRAME.
A
LOCATION
SHOULD
BE
SELECTED
WHICH
WILL
PROVIDE
EASY
ACCESS
·~
·
ANO
~L~~
~-
..
G?_9D
..~I·
E~
--
OF-
..
THE
.
FRON
_!
PANEL
METER
•.
THE
IN
STA-PEAK
.
II
SHOULD
NOT
BE
LOCAJED
D~RECTLY
ABOVE
HEAT
PRODUCING
EQUIPMENT.
2.2
ELECTRICAL
CONSIDERATIONS
FOR
BROADCAST
USE
THE
lNSTA-PEAK
11
HAS
SUFFICIENT
GAIN
TO
OPERATE
DIRECTLY
FROM
AN
EQUALIZED
TELEPHONE
LINE
AND
A
+20
DBM
OUTPUT
CAPABILITY
WHICH
IS
MORE
THAN
AMPLE
TO
ALLOW
DIRECT
CONNECTION
TO
THE
TRANS-
MITTER.
MOST
TRANSMITTERS
REQUIRE
AN
INPUT
LEVEL
OF
+10
DBM
FOR
100%
MODULATION.
JF
THE
INSTA-PEAK
I I
IS
TO
BE
USED
AT
THE
STUDIO
OR
IF
IT
IS
'I
I
~
TO
s;
1
~PERATED
FROM
A
STL
llECEIVER,
SUFFICIENT
FIXED
AUDIO
ATTE~~ATIO~
SUCH
AS
A
II
T"
PAD
SHOULD
BE
INSTALLED
AHEAD
OF
THE
fNPUT
TERMINALS.
A
10
OB
ATTENUATOR
AT
THE
OUTPUT
TERMINALS
IS
.~:.
'
RECOMMENDED
WHEN
FEEDING
A
TELEPHONE
LlNE
SO
THAT
THE
NORMAL
AMPLIFIER
$UTPUT
CAN
BE
SET
FOR
+10
DBM.
ATTENUATOR
CIRCUITS
AND
COMPONENT
VALUES
ARE
GIVEN
IN
FIGURE
2.1.
/
2.3
USE
OF
PRE-EMPHASIS
AND
DE-EMPHASIS
THE
INSTA-PEAK
JI
CONTAINS
PRE-EMPHASIS
AND
A
DE-EMPHASIS
·
CIRCUITS
IN
THE
MAIN
AMPLIFIER
CHAIN
FOR
THE
PURPOSE
OF
HIGH
FREQUENCY
WAVE
FORM
INTEGRATION
AND
INTERNAL
NOISE
REDUCTION.
2-1

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THE
LEVEL
CONTROLLING
AMPLIFIER
USES
SUFFICIENT
PRE-EMPHASIS
TO
COMPENSATE
FOR
THE
75
OR
25
MICROSECOND
RESPONSE
RISE
IN
THE
TRANSMITTER.
2,4
STEREO
INTERCONNECTION
WHEN
A
PAIR
OF
INSTA-PEAK
11
PROCESSORS
ARE
USED
FOR
STERE~
.
,ROAOCASTING,
THE
LEFT
ANO
RIGHT
CHANNEL
GAIN
REDUCTION
CIRCUIJ$
CAN
BE
INTER-CONNECTED
BY
MEANS
OF
THE
JUMPER
CABLE
,,\
'\·
1
SUPPLl~Q,
THIS
CAUSES
BOTH
CHANNELS
TO
HAVE
EQUAL
GAIN
REDUCTION
•
·,'
!
•,I
EVEN
T~OUGH
ONLY
ONE
CHANNEL
ACTUALLY
REQUIRES
COMPRESSION
OR
GAIN
1 I
,'•,
REDUCTION.
THE
SAME
TECHNIQUES
CAN
BE
USED
FOR
QUADROPHONIC
BROADCASTING.
HOWEVER,
A
SPECIAL
INTER-CONNECTION
CABLE
IS
REQUIRED.
215
ELECTRICAL
CONNECTIONS
THE
flVE
TERMINAL
BARRIER
STRIP
LOCATED
ON
THE
REAR
OF
THE
.-
.
INSTA-PEAK
II
IS
USED
FOR
INPUT
AND
OUTPUT
CONNECTIONS
AS
WELL
AS
\ .
SHIELD
GROUND.
POLARITY
OF
THE
INPUT
AND
OUTPUT
LINES
MUST
BE
OBSERVED
WHEN
CONNECTING
FOR
STEREO
OPERATION.
NOMINAL
INPUT
AND
OUTPUT
IMPEDANCES
ARE
600
OHMS
WITH
TRANSFORMER
JSOLATION.
THE
OUTPUT
SOURCE
IMPEDANCE
IS
125
OHMS
•
.
~
THE
STEREO
INTER-CONNECTION
CABLE
PLUGS
INTO
THE
JACKS
\
·•
!1
/
2-2