Studio Technologies IFB Plus User Manual
ISS
User Guide
ISS
Integrated Simulator System
Issue 3, June 1990
© 1994 Studio Technologies, Inc.
5520 West Touhy Avenue
Skokie, Illinois 60077 U.S.A.
Telephone (847) 676-9177
Fax (847) 982-0747
www.studio-tech.com
50152-690, Issue 3
ISS
Table of Contents
Introduction ................................................................................... 5
Installation .....................................................................................6
Using the ISS ................................................................................ 13
Technical Notes ............................................................................17
Technical Description ................................................................... 24
Appendices
Appendix A
Specifications .......................................................................... 37
Appendix B
ISS Alignment Notes ............................................................... 38
Figures
Figure 1
ISS Connection Diagram ......................................................... 44
Figure 2
ISS Ribbon Cable Bus............................................................. 45
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Issue 3, June 1990 ISS User Guide
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Introduction
Your ISS was inspected and carefully
checked at the factory. We suggest, however, that you inspect the shipping cartons
and all contents for any damage.
If you do find damage, save the cartons and
all packing material and notify the shipper.
You are responsible for any shipping claims
that must be made.
The shipping carton will contain your ISS
mainframe, ISS circuit cards, ISS front
panel, ISS instruction manual, mainframe
instruction manual, warranty cards, and a
power cord. If any of these materials are
missing, contact your dealer or Studio
Technologies, Inc. immediately.
General Description
The Studio Technologies ISS Integrated
Simulator System is designed for use in
conjunction with MTS television broadcast
operations. The television broadcaster is
faced with the reality of having to broadcast
a combination of stereo and mono audio
material. Stereo simulators can greatly
improve the listeners appreciation of stereo TV. The ISS combines excellent stereo
simulation with advanced control circuitry
to provide superior audio and operational
performance.
Major Functions
The ISS provides several major functions:
Stereo Simulation: The ISS produces great
sounding simulated stereo. To create this
sound the ISS contains two stereo simulator circuit cards. These cards work together
to transform a mono signal into left and
right channel signals that give an excellent
stereo feel, while keeping the voice signals in the center. The ISS Type I simulator
card provides simulation over the entire
audio spectrum. The Type II simulator card
adds a specialized filter to give greater
simulation to all frequencies except those in
the voice band. The Type II card ensures
that excellent voice centering is maintained.
The simulated stereo is completely mono
compatible. The sound of the ISS is factory
optimized for the best overall performance.
Input/Output Circuitry: The input/output
circuitry of the ISS provides switch selectable 0, +4, or +8dBu operation to match
the requirements of most broadcast facilities. Careful circuit design provides excellent audio performance. The Transfer Relay
Assembly connects the audio input signals
directly to the audio output connectors in
the event of a system malfunction, power
failure, or operator request, thus ensuring
no interruption of broadcast audio.
Audio Control: A smooth electronic
crossfade circuit routes either the line inputs, or the outputs of the stereo simulator
cards to the ISS line outputs. Three crossfade speeds are used to ensure the appropriate action. The ISS has been designed
to provide the best simulated stereo sound
with the least obtrusive operation.
Remote Control Operation: Extensive features allow the operating status of the ISS
to be displayed and controlled remotely.
Relay contacts provide system status indication. These are also known as tally signals. Continuous or pulse logic level inputs
give the user complete control over the ISS
operating status.
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Mono/Stereo Recognition: The Recognition
Card determines the mono/stereo status
of the incoming left and right audio signals.
The Recognition Card contains circuitry
to determine if the incoming audio is two
channel mono, mono with signal on the left
channel only, or mono with signal on the
right channel only. Each condition can be
defeated by a switch. The circuitry has been
designed to minimize the chance of incorrect recognition, i.e., seeing a true stereo
input as mono, or vice versa.
Polarity Correction: ISS circuitry can monitor and correct 180 degree polarity reversals. The Polarity Correction Card ensures
that mono compatibility is maintained.
Design Criteria
We are pleased that you already have, or
will soon be purchasing an ISS. A great
deal of care and effort was put into developing this product. Our first design requirement was that the simulated stereo produced must sound very good. We, by all
means, love real stereo recordings, but
these, especially for TV broadcasters, are in
limited supply. The ISS provides the stereo
listener with a high quality, enhanced version of the mono source.
The second design criteria was to provide
the broadcaster with a set of features that
would allow complete interfacing into their
broadcast facility. We required that the
completed ISS have the operational characteristics to integrate easily with existing
facilities. We hope you share our enthusiasm about the ISS. Questions and comments can be directed to Gordon Kapes,
president of Studio Technologies. Your
praise or verbal thrashing is welcome!
Jim Cunningham designed the audio sections in the ISS. He is responsible for the
very effective stereo simulation method
used. Mitch Budniak designed most of the
logic circuitry and made suggestions that
added considerably to the overall reliability
of the ISS. The printed circuit cards were
designed by Fred Levine. Gordon Kapes
designed the overall architecture and coordinated the project.
Installation
Overview
In this section you will be:
Taking an ISS inventory
Mounting and powering the ISS
Mainframe
Connecting the audio signals
Connecting the remote control input
signals
Connecting to the status relay outputs
Configuring the circuit cards
Getting Ready
Carefully remove the ISS Mainframe from
the shipping carton. For protection, the
circuit cards are shipped installed in the
mainframe. Use your fingers to take out the
four front panel fasteners, allowing the front
panel to be removed. You can now take an
inventory:
Qty Description
1 Mainframe
1 Front Panel
4 Front Panel Fasteners (knurled screws)
1 Power Cord
1 Ribbon Cable Bus
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ISS
1 ISS Manual (youre reading it!)
1 Mainframe Manual
2 Warranty Cards
1 I/O Card
1 Type I Simulator Card
1 Polarity Correction Card
1 Type II Simulator Card
1 Recognition Card
1 Crossfade Card
1 Mode Select Card
An extender card can be purchased as an
option and may be part of your system. It
consists of 4 pieces: two ribbon cables and
two interface boards.
In some cases you may have purchased a
Tone Detection Card. It is an option and in
most cases will not be present.
Mounting
The ISS is rack-mountable, requiring three
standard rack spaces (5.25") in a standard
EIA 19.00" rack. Ensure that air flow is
maintained, especially on the right side
(when looking from the front) where the ISS
power supply section is located. A good
basic rule to remember is that most electronic equipment failures are power supply
related. Power supplies tend to generate
heat which, when not adequately dissipated, serve to cook the power supply,
drying out electrolytic capacitors and
stressing semiconductor junctions. Keeping
all equipment relatively cool will reduce the
likelihood of problems occurring.
Connecting the Unit to Power
The ISS may be operated from either nominal 115 or 230Vac, 50/60 Hz. Units selected
for 115V operation utilize a 0.75A 3AG
Slow-Blow fuse; 230V operation utilizes a
0.375A Slow-Blow fuse. Before connecting
the ISS to power, determine the actual line
voltage and check to see that the voltage
selector switch, visible through the square
cutout in the Transfer Relay Assembly, is
set to the appropriate voltage. If the voltage
selector switch is set for 230V, ensure that
the fuse, located adjacent to the voltage
selector switch, is 0.375A. PLEASE NOTE
THAT AN INCORRECT SETTING AND/OR
INCORRECT FUSE COULD SERIOUSLY
DAMAGE THE UNIT.
The ISS utilizes an IEC standard connector
to mate with the line cord. The line cord
supplied has a North American standard
plug at one end and an IEC connector at
the other. In non-North American applications, the plug must be cut off and an appropriate plug attached. The wire colors in
the line cord conform to the internationally
recognized CEE color code and should be
wired accordingly:
Connection Wire Color
Neutral (N) Light Blue
Live (L) Brown
Protective Earth (E) Green/Yellow
Signal Connections
All signal connections to and from the ISS
are made via connectors located on the
back panel. Four, three pin XL-type connectors handle audio input and output signals;
female for input, male for output. One
25-pin male D-type subminiature connector
handles all remote control and status signals. Refer to Figure 1, located at the end
of this manual, for detailed connection
information.
Audio Signals
Left and right audio input and output connections must be made. For hum, noise,
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ISS
and RF pickup rejection, shielded cable
must be used for the audio signals. Studio
Technologies uses the convention of pin 2
high, in honor of the European microphone
makers! In most cases, it is correct to
connect the shield lead to pin 1 of the XL
connectors. Pin 1 on the audio input and
output connectors are common with the ISS
Mainframe power supply ground, chassis
ground, and power cord ground leads.
Maintaining consistent left and right audio
input and output polarity is very important
for correct performance of the ISS.
If possible, use patch points on the input
and output signals of the ISS. Installation,
testing, and servicing procedures will be
greatly improved if the ISS is easily placed
on and off line. Make sure that the ISS can
be patched around while allowing test
signals to be sent to and returned from
the ISS.
The ISS audio input signals generally arrive
from the master control switcher, an STL,
leased telephone lines, etc. All audio processing (limiting, compressing, etc.) should
be performed prior to the audio getting to
the ISS. This helps to ensure that the ISS
simulated stereo remains mono compatible.
The source should be balanced and line
level. If the audio equipment contains audio
output transformers, load resistors matching the source impedance may need to be
inserted and soldered into the I/O card. In
many cases the value of the resistors would
be 600 ohms. Loading of the output transformers can prevent ringing of the audio
signals. The quality of the output transformers is the determining factor when deciding
whether to load or not to load. Bad transformers tend to need loading; good ones
generally do not. Refer to the Technical
Notes section of this manual for more
information on installing load resistors.
The ISS audio output signals usually go
directly to the transmitter, or to the transmitter via an STL or leased lines. The ISS
audio outputs are low impedance, electronically balanced, line level, direct coupled.
They are capable of driving virtually all line
inputs (low or high impedance, transformer
or transformerless). The ISS can even drive
150 ohm loads at high signal levels, not
bad huh!
The ISS uses electronically balanced input
and output circuitry. Best performance is
achieved if the equipment sending signal
to, and receiving signal from the ISS is
operating in a balanced mode. The ISS
input and output stages will operate correctly in an unbalanced mode, but selected
performance characteristics will be sacrificed. On the input side you will lose the
ability to reject common-mode signals that
balanced operation affords. On the output
side you will lose 6dB maximum output
level. This is not a technical fault but is
inherent in electronically balanced output
stages. If unbalanced input operation is
required, strap pin 3 to pin 1 on the male
connector that will mate with the ISS. Connect the unbalanced input signal high lead
to pin 2, and signal ground to pin 1. If
unbalanced output operation is required,
strap pin 3 to pin 1 on the female connector
that will mate with the ISS. Connect the
unbalanced output signal high lead to pin 2,
and signal ground to pin 1.
In most cases, transformer coupling between audio equipment is neither required,
nor desirable. If the equipment sending
signal to, or receiving signal from the
ISS requires the isolation given by a
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ISS
transformer, but does not contain internal
transformers, external transformers can
be added. Refer to the Technical Notes
section of this manual for recommended
transformers.
Connecting the Remote Control Signals
Provision has been made for remotely
controlling a number of ISS functions.
These signals interface with the ISS via a
25-pin male D-type connector located on
the back panel. In most cases, the ISS will
be located some distance from the TV
master control point. It may be desirable to
control the ISSs operation using a telemetry system or switches connected via cable
pairs. The following is a description of the
remote control inputs:
Remote Control Enable: Activating this
allows use of the Remote Simulate from
Left and Remote Simulate from Right commands. Activating the Remote Control
Enable will override the commands from the
Recognition Card.
Remote Polarity Correction Function
Disable: Activating this command disables
the polarity correction function.
Low voltage, current limited logic type
signals are required for remote control
operation. Continuous or pulse (momentary) signals can be used. These logic
signals are usually nominally 5 or 12Vdc.
LED based optical couplers, located on the
ISS circuit cards, are utilized to eliminate
interfacing problems. The couplers require
current, rather than voltage or a contact
closure, to operate. The minimum current
required is 4mA; the maximum is 20mA. For
protection, 680 ohm resistors, located on
the ISS circuit boards, are in series with the
optical couplers. These resistors limit a
5Vdc signal to 4.5mA, and limit a 12Vdc
signal to 13mA. If higher DC voltages are
used, additional current limiting resistors,
connected in series with the remote control
inputs, are required. Failure to provide
current limiting will damage and/or shorten
the life of the opto couplers.
Remote Simulate from Left: This command
is only active when Remote Control Enable
is in effect. Remote Simulate from Left
allows you to place the ISS in the simulate
from the left channel mode.
Remote Simulate from Right: This command
is only active when Remote Control Enable
is in effect. Remote Simulate from Right
allows you to place the ISS in the simulate
from the right channel mode.
Remote I/O Bypass: Activating this command forces the relays on the Transfer
Relay Assembly to release, connecting the
audio input signals directly to the audio
output connectors. This electrically takes
the ISS out of the audio path.
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Studio Technologies, Inc. Page 9
Connecting to the Status Relay Outputs
Relay contacts indicating several ISS operating characteristics are provided for userdesignated functions. These contacts are
accessible via the 25-pin male D-type connector located on the back panel. These
can be extremely useful for local or remote
monitoring. An automation system can
watch for an error condition, or a master
control operator can monitor ISS operation
through a set of indicator lights. Dry (isolated) relay contacts are provided so that
virtually any monitoring scheme can be
implemented without interfering with ISS
operation due to ground loops, noise
pickup, etc. The following gives a description of the Status Relay Outputs.
ISS
ISS Remote Control Enabled: This contact
closes (shorts) when a Remote Control
Enable condition is in effect. This contact
gives acknowledgment of a valid Remote
Control Enable condition.
ISS Simulating from Left: This contact
closes (shorts) when the ISS is in the simulating from the left channel mode. This
contact closes any time the ISS is simulating from the left channel, whether due to
a Remote Simulate from Left command,
a command from the front panel controls,
or a command from the Recognition Card.
ISS Simulating from Right: This contact
closes (shorts) when the ISS is in the simulating from the right channel mode. This
contact closes any time the ISS is simulating from the right channel, whether due to
a Remote Simulate from Right command,
a command from the front panel controls,
or a command from the Recognition Card.
Polarity Correction Taking Place: This contact closes (shorts) when polarity correction
is taking place. You may want to let this
contact control an audible alerting device
in master control, a tape room, etc. The
audio source may need to be corrected,
or at least marked to show that a polarity
reversal is present.
Polarity Correction Function Disabled: This
contact closes (shorts) when a Remote
Polarity Correction Function Disable condition is in effect. This contact acknowledges
a valid Polarity Correction Function Disable
command.
Configuring and Installing the Circuit
Cards
Once the connections have been made, the
cards are ready to be configured. Do not
remove or insert any of the cards with the
mainframe power on. Do not hot install or
remove the cards! We will be working with
the cards in the order in which they are
housed in the cabinet: left to right, when
viewed from the front.
Mainframe card position 1 is on the left side
(viewed from the front); card position 9 is
on the right side.
The ISS mainframe is shipped with the
cards installed and the ribbon cable bus
attached. If you havent done so already,
carefully remove the ribbon cable bus from
all the cards. The connector on the front of
each card has latches that must be opened
for the ribbon cable bus connector to be
removed. Dont fear the ribbon cable bus!
It is fast, reliable, and easy to work with.
Once you are used to it, youll like it!
I/O Card: The ISS is designed to accept
nominal audio signal levels of 0, +4, or
+8dBu. The desired input and output levels
must be set using the two switches located
on the I/O Card. Remove the I/O Card from
mainframe position 1 (the far left position
when facing the front of the mainframe).
The INPUT LEVEL switch selects the nominal line input level for both channels. The
OUTPUT LEVEL switch sets the nominal
output level. Set these switches to match
your broadcast facilitys desired nominal
operating level. The A position corresponds
to 0dBu operation, the B position to +4dBu,
and the C position to +8dBu. The nominal
input and output levels do not have to be
the same. If input loading is required, refer
to the Technical Notes section of this
manual. After setting the switches, and
possibly installing load resistors, install the
card back into mainframe position 1. Remember, do not install this or any card
when the mainframe power is on.
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Type I Simulator Card: Remove the Type I
Simulator Card from mainframe position 2.
In addition to the identification label, this
card can be identified by the empty parts
locations on the circuit board. You will
observe a section in the middle of the board
where parts have not been inserted. There
are no switches to be set, or initial adjustments to be made on the Type I Simulator
Card. Confirm that single turn trim potentiometer R43 is set to the 50% rotation point,
i.e., halfway between fully clockwise and
fully counterclockwise. R43 is small and
basically round, and is located near the
front edge of the card. This pot was preset
at the factory but a visual check is a good
idea. DO NOT TOUCH ANY OTHER POTENTIOMETER ON THIS CARD OR FACTORY CALIBRATION MAY BE REQUIRED.
This card is now installed in mainframe card
position 2.
Polarity Correction Card: Remove the Polarity Correction Card from mainframe position
3. One switch must be set on the Polarity
Correction Card. This switch determines the
type of remote control signal that is going to
be used for the Remote Polarity Correction
Function Disable command. In the CONT
position a continuous signal will be applied.
In the PULSE position a momentary signal
will be applied. If you are not going to be
connecting a remote control signal the
switch should be in the CONT position. This
card is now installed in card position 3.
Type II Simulator Card: Remove the Type II
Simulator Card from mainframe position 4.
In addition to the identification label, this
card can be identified by the fact that,
unlike the Type I card, most of the components in the Type II printed circuit board
have been inserted. There are no switches
to be set, or initial adjustments to be made
on the Type II Simulator Card. Confirm that
single turn trim potentiometer R43 is set to
the 50% rotation point, i.e., halfway between
fully clockwise and fully counterclockwise.
This pot is in the same location, and is
labeled R43 on both the Type I and Type II
cards. This pot was preset at the factory
and should only require a visual confirmation of the correct setting. This card is now
installed in card position 4.
Crossfade Card: Remove the Crossfade
Card from mainframe card position 5. One
switch, INPUT, must be set on the Crossfade Card. This switch selects which audio
signal is connected to the card from the
ribbon cable bus. If, as is usual, the Polarity
Correction Card is installed, set the switch
to the B position. If, for reasons such as
repair, etc., the Polarity Correction Card is
not installed, set the switch to the A position. If a Tone Detection Card is present in
your system the INPUT switch is set to the
C position. This card is installed in card
position 5.
Recognition Card: Remove the Recognition
Card from mainframe card position 6. There
are two switches that must be set on the
Recognition Card. The INPUT switch selects which audio signal is connected to the
card from the ribbon cable bus. If, as is
usual, the Polarity Correction Card is installed, set the switch to the B position. If,
for reasons such as repair, etc., the Polarity
Correction Card is not installed, set the
switch to the A position. If a Tone Detection
Card is present in your system the INPUT
switch is set to the C position. The other
switch is a four position DIP type. This
switch decides which recognition modes
will be active. One, two, or all three modes
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ISS
can be turned on at the same time. Switch
position 1 controls if L=R is recognized as
mono. Place switch position 1 to ON if you
want a mono signal on both left and right to
be recognized as mono. Switch position 2
controls if a signal on the left channel only
will be recognized as mono. Place switch
position 2 to ON if left only is to be recognized as mono. Switch position 3 controls
if a signal on the right channel only will be
recognized as mono. Place switch position
3 to ON if right only is to be recognized as
mono. Remember that all three modes can
be, and in most cases will be, turned on at
once. Switch position 4 is not used and
should be left in the OFF position. Confirm
that the single turn trim potentiometer R10
is set to the 50% rotation point, i.e., halfway
between fully clockwise and fully counterclockwise. It is the only trim pot on the
Recognition Card. The pot was preset at
the factory, but a visual double check is
a good idea. This card is now installed in
card position 6.
Mode Select Card: Remove the Mode
Select Card from mainframe card position
7. One switch must be set on the Mode
Select Card. This switch determines the
type of remote control signals that are
going to be applied to the four remote
control inputs: Remote Control Enable,
Remote Simulate from Left, Remote Simulate from Right, and Remote I/O Bypass. In
the CONT position, continuous signals will
be applied. In the PULSE position, momentary signals will be applied. If remote control
signals are not going to be connected, the
switch should be set to the CONT position.
This card is now installed in card position 7.
Card Position 8: Card position 8 is reserved
for an option, the Tone Detection Card. This
card places the ISS in the electronic bypass
mode if a continuous, specific frequency
is detected. If your installation includes
this card, refer to the separately supplied
documentation for complete installation
instructions.
Card Position 9: Card position 9 is not
utilized at this time.
The Ribbon Cable Bus
Once the cards are configured and reinstalled, the ribbon cable bus can be installed, linking all the cards together. Start
with the I/O card, located in card position 1,
and work to the right. Orient the ribbon
cable bus so that the colored stripe, usually
red or blue, that indicates pin 1 will mate
with the top pins of the card connectors.
Mate the left most ribbon cable bus connector with the I/O Card connector. A mechanical key on the I/O Card prevents the ribbon
cable bus from being installed upside
down. Repeat this process for the remainder of the cards. Use the latches to secure
the ribbon cable bus connectors to the card
connectors.
For future reference note that the ribbon
cable bus can be removed or attached with
the mainframe power on or off. The ribbon
cable bus carries only audio and logic
signals. No damage will occur if one or
more of the cards are operated with their
respective ribbon cable bus connectors
disconnected. Remember that the cards
themselves cannot be hot plugged into,
or pulled out of, the mainframe.
Securing the Front Panel
Carefully place the front panel over the front
of the mainframe and secure using the four
screws.
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Using the ISS
In this section we will first review the controls and indicator lights on the ISS front
panel. Next we will run some basic tests on
the system and give you a feel for its operation.
I/O Card
One LED and one switch relate to the I/O
Card and its functions. When lit, the green
NORMAL LED indicates that the relays on
the Transfer Relay Assembly, located on the
back panel, are energized and that the
audio input and output signals are connected to the ISS circuitry. When the NORMAL LED is off, the relays on the Transfer
Relay Assembly de-energize, directly connecting the left line input to the left line
output, and the right line input to the right
line output. The NORMAL LED will not light
if a valid remote I/O Bypass command is
received, if the I/O switch is in the I/O
BYPASS position, or if a power supply
error is detected. A red LED on the Transfer
Relay Assembly mimics the operation of the
I/O cards LED. This LED is visible through
an access hole in the back panel.
When the I/O switch is in the I/O BYPASS
(down) position, the Transfer Relay Assembly is held in the I/O Bypass mode, removing the ISS from the audio path. In the
NORMAL (middle) position, the ISS will be
in the audio path but will ignore a remote
command to go into the I/O Bypass mode.
In the NORMAL + REMOTE (up) position,
a remote command to initiate I/O Bypass
will be executed.
Polarity Correction
Two LEDs and one switch relate to the
Polarity Correction Card and its functions.
When the red CORRECTING LED is lit, it
indicates that a polarity reversal has been
detected and is being corrected.
When the yellow REMOTE DISABLED LED
is lit, it indicates that the polarity correction
function is disabled via the remote control
input.
When the switch is in the DISABLE (down)
position, the polarity correction function has
been turned off. This is useful when testing
the ISS or related equipment. In the OPERATE (middle) position, the polarity correction function is active but the card will
ignore a remote control command to go
into the disable mode. In the OPERATE +
REMOTE (up) position, a remote command
to disable the polarity correction function
will be executed.
System Status
Three LEDs indicate the bypass/simulate
status of the ISS. When the green BYPASS
LED is lit, it indicates that the electronic
crossfade circuitry is routing the input audio
to the audio outputs; the stereo simulators
are not in the audio path. When the red SIM
LEFT LED is lit, it indicates that the left
audio input is being sent to the simulators
and the resulting simulated stereo signal is
being sent to the audio outputs. When the
red SIM RIGHT LED is lit, it indicates that
the right audio input is being sent to the
simulators and the resulting simulated
stereo signal is being sent to the audio
outputs.
ISS User Guide Issue 3, June 1990
Studio Technologies, Inc. Page 13
ISS
Mode Select
One LED and two switches relate to the
Mode Select Card and its functions. When
lit, the yellow REMOTE LED indicates that
the ISS bypass/simulate status is being
controlled via remote control, indicating that
the remote manual mode is in effect.
The top switch, SYSTEM MODE, sets the
overall ISS operating mode. In the MANUAL
(down) position, the bypass/simulate status
is controlled by the lower switch. In the
AUTO (middle) position, the Recognition
Card will control the bypass/simulate status,
but a remote control override request is
ignored. In the AUTO + REMOTE (up)
position, the remote control override can
be used.
The lower switch, MANUAL, is active
when the SYSTEM MODE switch is in the
MANUAL (down) position. The MANUAL
switch selects bypass, and simulate from
the left input or simulate from the right input
operation.
A method of monitoring the ISS audio
outputs is also required, such as a set of
high quality audio speakers with an associated power amplifier. Set up the speakers
so that a good stereo image can be heard;
i.e., dont put them too far apartset them
up in a normal listening position. Set the
audio amplifier level controls to the OFF
position. Headphones are also a good
method of monitoring.
1) Check to ensure that audio is indeed
feeding the ISS.
2) Set the following ISS switches: I/O
switch to BYPASS, POLARITY CORRECTION switch to DISABLE, SYSTEM
MODE switch to MANUAL, and
MANUAL switch to BYPASS.
3) Push the ISS power switch to the ON
(in) position. The red LED located just
above the power switch should light.
Of the other LEDs, only the green
BYPASS LED on the Crossfade card
should be lit.
Initial Operation
The installation is over and youre somewhat familiar with the controls; now the fun
can begin as you see what the ISS can do.
You must first connect a source of audio to
the ISS inputs via your patch bay. A good
signal source would be left and right audio
from master control via an audio router; a
better signal would be a great sounding
compact disc run through a line amp to
come up to your required audio level! Do
not use sine waves, or other obscure nonprogram type signals in these tests. The
ISS was designed to work with actual program material!
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4) Raise the level of the audio amplifier
until your left and right test signals are
comfortably heard. You are listening to
the input signals connected directly to
the audio outputs via the Transfer Relay
Assembly.
5) It is a good idea to ensure that at the
start of our tests, audio input and output polarity has been correctly connected. To test this, feed the same
signal into the left and right inputs.
Sum the left and right audio outputs
and listen to the resulting mono signal.
You should not have any cancellation,
as this would indicate a 180 degree
reversal on an audio input or output.
ISS
The easiest way to listen to L+R is to
use an audio amplifier with a mono
button on it. Of course, you can always
use a scope to determine if the polarity
of the wiring or associated patch bay is
correct. Get this test over with now and
you wont have to worry about it later!
Be warned that a polarity reversal on
the same channels input and output
will not show up with this test. A
double flip could later lead to incorrect Polarity Correction Card or Recognition Card performance. After you have
confirmed the connection polarity you
should resume monitoring in stereo.
6) Place the I/O switch to the NORMAL
position. The green NORMAL LED on
the I/O Card should light; the red LED
on the Transfer Panel Assembly should
also light. You should hear audio at the
same level as heard in the previous
step. You are hearing audio through
the ISS circuitry! If the level does not
match, the most likely cause is an
incorrect INPUT LEVEL or OUTPUT
LEVEL switch setting on the I/O Card.
Recheck your switch settings.
7) Move the MANUAL switch to the SIM
LEFT position. The BYPASS LED will
fade out while the SIM LEFT LED will
light up. The audio you hear is stereo
simulated from the left input channel.
Listen to the left and right output signals
in mono. The simulated stereo effect
should drop out and you should hear a
faithful rendition of the left input signal.
If listening to the sum (L + R) of the ISS
outputs degrades the level and/or
quality of the audio you most likely have
a double flip, as was discussed in
step 5. This mono compatibility problem must be corrected NOW! Once you
confirm mono compatibility, move the
MANUAL switch back to the BYPASS
position. The output will fade from
simulated stereo back to the input
signals. Try simulating from the right
audio input by moving the MANUAL
switch to the SIM RIGHT position. Then
return the MANUAL switch to BYPASS.
8) Place the SYSTEM MODE switch to the
AUTO position. This lets the ISS mode
be controlled by the Recognition Card.
Remember, during system setup you
chose which of the three recognition
modes you wanted active. Most people
will have enabled all three modes, so
mono will be recognized as L=R, left
only, and right only.
Feed a stereo signal into audio inputs.
Remember, do not use sine waves as
your signal source. The BYPASS LED
should be lit.
Feed a mono signal into both the left
and right audio input. If you enabled
L=R is mono, the SIM LEFT LED will
light showing the ISS is simulating
stereo from the left input. If you did not
enable L=R is mono, then the ISS will
stay in the Bypass mode.
Feed a signal only into the left audio
input. If you enabled left only is mono,
the SIM LEFT LED will light showing the
ISS is simulating stereo from the left
input. If you did not enable left only is
mono, then the ISS will stay in the
Bypass mode.
Feed a signal only into the right audio
input. If you enabled right only is mono,
the SIM RIGHT LED will light showing
the ISS is simulating stereo from the
right input. If you did not enable right
ISS User Guide Issue 3, June 1990
Studio Technologies, Inc. Page 15
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