NVision NV1023 User manual

NV1023 SDIF-2 Distribution Amplifier 1
CONTENTS: 1. GENERAL DESCRIPTION
2. CONFIGURATION AND
INSTALLATION
3. OPERATION
4. FUNCTIONAL DESCRIPTION
5. MAINTENANCE AND
TROUBLESHOOTING
6. DRAWINGS AND SCHEMATICS
7. APPENDICES AND CHANGE
INFORMATION
Nvision@
NV1023 Instruction Manual
SDIF-2 Distribution Amplifier
Manual Part No. MI1023-01
April, 1996

2 NV1023 SDIF-2 Distribution Amplifier
Table 1 - NV1023 Performance Specifications
Input
Impedance: Jumper configurable for 75 ohms or high impedance.
Level: TTL
Data Rate: SDIF-2 Word Clock, 28 kHz - 54 kHz (typical)
Outputs
Number: 4
Impedance: Low
Level: TTL
Mechanical
Size: 90 mm x 25 mm x 370 mm (3-1/2" x 1" x 14-1/2")
Power Source: NV1000 Rack Frame (Assembly FR1000)
Power Consumption: 3 Watts
Backplane(s): SDIF-2 BNC Backplane Assembly EM0104

NV1023 SDIF-2 Distribution Amplifier 3
1. GENERAL DESCRIPTION
1.1 OVERVIEW
The NV1023 SDIF-2 Distribution Amplifier provides a low-cost
solution for the distribution of SDIF-2 digital audio word clock to
multiple destinations.
The NV1023 comprises a plug-in active module and a BNC connector
backplane, Assembly EM0104. This backplane, mounted in the rear of
any of the 12 active module slots in an NV1000 terminal equipment
frame (Assembly FR1000), provides the connection interface for
external signal cables.
Figure 1 illustrates the NV1023 interface and connections. Table 1
lists NV1023 performance specifications.
J1
J2 SDIF-2 Output
Figure 1 - NV1023 Input/Output Connection (SDIF-2 BNC Backplane)
EM0104 Backplane
NOTE: Inputs and Outputs are
transformer coupled through
DC voltage blocking capacitors.
SDIF-2 Output
SDIF-2 Output
SDIF-2 Output
SDIF-2 Input
Loop-Thru
(Optional)
J3
J4
J6
J5

4 NV1023 SDIF-2 Distribution Amplifier
1.2 SIGNAL DISTRIBUTION APPLICATIONS
The NV1023 is a signal distribution amplifier for sending SDIF-2 digital
audio word clock to multiple destinations from a single source. It
expands the number of possible destinations for a single source from
one to as many as four.
With its input loop-through capability, several NV1023 amplifiers can
be configured to drive many more destinations. This cost-effective
topology is especially attractive when used for distributing SDIF-2 word
clock to a large number of locations. However, greater attention must
be given to good transmission-line engineering when connecting
distribution amplifiers in this manner.
It is vital that:
1. Coaxial cables have a characteristic impedance of 75 ohms.
2. The cable is terminated at the far end with 75 ohms. Connections
within the daisy chain must loop through equipment that has low
input return loss and whose input impedances are high relative to
the cable's characteristic impedance. NVISION SDIF-2 signal
distribution and processing equipment meets this criteria when
configured for high input impedance.
3. Cable lengths are minimized, and the legs of the chain past the first
connection are short and of roughly equal length.
Figure 2 illustrates a poor technique for looping a signal through
multiple pieces of equipment. The distance between devices is longer
than the distance from the source to the first device. A better topology
is illustrated in Figure 3.
The theoretical limit for the number of connections in a chain of
NV1023 distribution amplifiers is 18. The practical limit is between six
and eight, depending on cable length and quality.
Figure 4 illustrates the preferred topology for configuring multiple
NV1023 DAs for use in high fanout applications.

NV1023 SDIF-2 Distribution Amplifier 5
3 meters (10 feet)
10 meters (30 feet)
15 meters (45 feet)
SDIF-2
Source
High Impedance
Termination
High Impedance
Termination
High Impedance
Termination
NV102x Distribution Amplifiers (x3)
Figure 2 - Poor Signal Loop-
Through Methodology
50 meters (150 feet)
0.5 meters (1.5 feet)
0.5 meters (1.5 feet)
SDIF-2
Source
High Impedance
Termination
High Impedance
Termination
75 Ohm
Termination
NV102x Distribution Amplifiers (x3)
Figure 3 - Good Signal Loop-
Through Methodology

6 NV1023 SDIF-2 Distribution Amplifier
Table 2 - NV1023 Jumper Settings
Jumper No. Setting Function
J1 1 - 2 Configures NV1023 for high input Z for loop-through applications.
2 - 3 Configures NV1023 for 75 ohm input impedance.
3 - 4 Configures NV1023 for high input Z for loop-through applications.
SDIF-2
Source
Figure 4 - Increasing Signal Fan-Out Capability Using Multiple DAs
To additional DAs (6-8 total, with
cable terminated at the last DA)
To additional DAs (6-8 total, with
cable terminated at the last DA)
To additional DAs (6-8 total, with
cable terminated at the last DA)
To additional DAs
(6-8 total, with
cable terminated
at the last DA)

NV1023 SDIF-2 Distribution Amplifier 7
2. CONFIGURATION AND INSTALLATION
CAUTION: IF YOU ARE INSTALLING FR1000 FRAMES AND PS2001
POWER SUPPLIES IN ADDITION TO NV1023
DISTRIBUTION AMPLIFIERS AT THIS TIME, YOU
SHOULD FOLLOW THE SYSTEM-LEVEL
INSTALLATION PROCEDURES FOUND IN THE NV1000
TERMINAL EQUIPMENT OPERATIONS INSTRUCTION
MANUAL (MANUAL PART NO. MI1000-01) LOCATED IN
THE FRONT OF THIS BINDER.
CAUTION: REMOVE POWER FROM THE FRAME IF THE
INSTALLATION INCLUDES THE CONNECTOR
BACKPLANE.
1. Replace the blank cover plates on the rear of the intended slot in
the NV1000 frame with the backplane assembly for the NV1023
distribution amplifier. The FR1000 frame is supplied with a 2.5 mm
Allen wrench for this purpose. Ensure proper alignment of the active
module to the backplane with the following procedure:
a. Install the EM0104 backplane with the screws loose.
b. Plug the active module into the loose backplane.
c. With the active module inserted, tighten the screws securing the
backplane.
d. Remove the module and reinsert it to make sure it is properly
aligned with the backplane and the card guides in the frame. If
the alignment is not good, repeat the above procedure. When a
satisfactory fit is obtained, remove the module and continue
with the installation.
2. Make cable connections to the rear panel per the drawings included
in the Applications section (See Section 1.2).
3. Set the input termination jumper on the active module as required
by the application. Refer to Table 2 - NV1023 Jumper Setting and
the Component Location drawing in Section 6 for information on
the jumper location and setting.
4. Apply AC line power to the frame and insert the PS2001 power
supply if it is not already in place.
5. Insert the active module with power applied to the frame.

8 NV1023 SDIF-2 Distribution Amplifier
3. OPERATION
Once configured for a particular application, the NV1023 SDIF-2
Distribution Amplifier needs no further attention. Refer to Section 5 -
Maintenance and Troubleshooting for recommendations on periodic
maintenance and performance checks.
4. FUNCTIONAL DESCRIPTION
Refer to the schematic diagram for the NV1023 active module
(Assembly EM0103) and the backplane drawing for Assembly
EM0104 during the following discussion.
The single-ended input to the NV1023 is a passive loop-through
connection, while the outputs are single-ended. While there are six
identical outputs on the active module, the BNC backplane assembly.
(EM0104) limits the number of available output connectors on the rear
panel to four.
4.1 INPUT CIRCUIT
Refer to page 1 of Schematic Diagram EM0103.
The signal enters the active module from the connector backplane
through interface connector J3 and is coupled to the input circuitry
through R4, a zero-ohm jumper in a resistor-like package. Jumper J1
provides a means for selecting the input termination resistance: 75 ohms
for terminating coaxial cables or high-impedance for loop-through
applications. Resistor R5 and voltage reference diode U5 bias the
inverting input of the RS-422 receiver integrated circuit (IC) U1 to +1.2
VDC. This provides a threshold for slicing the input signal and ensures
adequate noise rejection. Capacitor C5 provides a low-impedance
bypass for the reference diode at high frequencies.
4.2 OUTPUT CIRCUITS
See Schematic Diagram EM0103, page 2, and Schematic Diagram
EM0104.
The single-ended output of IC U1 is fed to six identical output circuits
comprising RS-422 driver ICs U2 and U3 and their associated circuitry.
One output circuit (Output #1) is described here; the others operate in
identical fashion.
SDIF-2 word clock data from pin 3 (output) of receiver IC U1 feeds pin
9 of quad RS-422 line driver IC U3. One side of the differential output
of U3C (non-inverting output, pin 10) is connected through zero-ohm
jumper/resistor R42 to input/output interface connector J3. From
interface connector J3, the single-ended signal enters SDIF-2 BNC
backplane EM0104, passes through zero-ohm resistor R4 and connects

NV1023 SDIF-2 Distribution Amplifier 9
to output BNC J3.
4.3 POWER
Refer to Schematic Diagram EM0103, page 3.
Pre-regulated power from the frame (+17 VDC) enters the module via
connector J2. Capacitors C18, C19 and inductor L2 filter the +17 VDC
power. Monolithic voltage regulator IC U4 provides regulated +5 VDC
for the active components on the NV1023 module. Schottky diode D1
catches the flyback voltage developed across the choke L2 when the
pass transistor in the switching regulator turns off. Capacitor C21 filters
residual noise on the +5 VDC to acceptable levels.
5. MAINTENANCE AND TROUBLESHOOTING
CAUTION: THE FOLLOWING PROCEDURES SHOULD BE
PERFORMED BY QUALIFIED SERVICE PERSONNEL
ONLY.
The NV1023 requires no electrical maintenance, although it is wise to
check periodically to ensure that the NV1000 equipment frame is
properly ventilated for cooling and that any optional fan assemblies are
free of dirt and obstructions.
Should an electrical problem arise, the following steps will help isolate
or eliminate it.
1. Assure normal NV1000 system power distribution as follows:
a. Observe the green LED on the PS2001 power supply module.
If illuminated, the line side of the supply connection is in order.
If it is not illuminated, ensure that the line cord is connected,
that the power-entry module fuse on the frame is intact, and
that the line voltage is correctly selected on the PS 2001 power
supply.
b. Confirm that the voltages at the test points on the front of the
PS2001 power supply match the values shown in Table 3 -
Acceptable Test Point Voltages for PS2001 Power Supplies. If
not, remove the active modules one at a time. If the removal of
one of the modules causes a restoration of the nominal supply
voltage, return that module to NVISION for repair. If removal
of all of the cards fails to restore the supply voltage, it is likely
that the power supply itself is at fault and should be replaced.
2. To determine if the NV1023 or the external equipment is at fault:
a. Where possible, replace the NV1023 with a known-good
module. If the fault remains, check the source equipment to
ensure a good signal is present at its output. Check all signal

10 NV1023 SDIF-2 Distribution Amplifier
cables for continuity or short circuits.
b. If the steps above indicate that the fault is in the NV1023
module or backplane, place the active module on an NVISION
extender module (Model Number NV10XX) for further testing.
Otherwise, return the module to NVISION for testing and
repair.
c. With an oscilloscope or a hand-held digital voltmeter, check first
for +5 VDC on test point TP2 using TP3 as a ground reference
point. If the indicated voltage is not present, ensure that +17
VDC ± 10% appears on the right side of capacitor C18 when
viewed from the component side of the module with the front
edge of the card to your left. If these voltages are not present,
find the faulty component or connection and replace or repair it.
d. If the proper voltages are present on the module, trace the
digital audio signal through the module using an oscilloscope
and probing test point TP1, the signal pins of U2 and U3, and
other components in the signal path. Isolate the faulty
component and replace it, or return the module to NVISION
for repair if you find that it is faulty.
NVISION Technical Support can be reached in California at +1 (916)
265-1000 between the hours of 8 am and 5 pm Pacific Standard Time.
6. DRAWINGS AND SCHEMATICS
Table 3 - Acceptable Test Point Voltages for PS2001 Power Supplies
PS2001 Test
Points Loaded Frame (One or More NV1000 Modules Installed) Unloaded Frame (No NV1000 Modules Installed)
±7 VDC 6 < IVI < 8.5 7 < IVI < 10*
±17 VDC 16 < IVI < 18.5 17 < IVI < 22*
* When unloaded, the upper voltage limit may exceed the value shown.

NV1023 SDIF-2 Distribution Amplifier 11
7. APPENDICES AND CHANGE INFORMATION
Applicable technical data, Application Notes and Field Modification
Notes that pertain to the NV1023 SDIF-2 Distribution Amplifier are
located here. Additional system information may be found in the
Appendix at the rear of the NV1000 Operations Manual. Reviewing
these materials will ensure that you are familiar with any product or
system-level information that may have changed or been added since
this Manual was printed.

12 NV1023 SDIF-2 Distribution Amplifier