evertz 7700 Series User manual

7700 MultiFrame Manual
7720ADC-A4 Analog Audio to AES Converter
Revision 1.1
1. OVERVIEW.......................................................................................................................................... 1
2. INSTALLATION................................................................................................................................... 2
2.1. ANALOG AUDIO CONNECTIONS ............................................................................................ 3
2.2. AES AUDIO CONNECTIONS..................................................................................................... 3
2.3. AES REFERENCE CONNECTIONS .......................................................................................... 3
3. SPECIFICATIONS............................................................................................................................... 4
3.1. ANALOG AUDIO INPUT: ........................................................................................................... 4
3.2. AES AUDIO OUTPUTS .............................................................................................................. 4
3.3. REFERENCE INPUT .................................................................................................................. 4
3.4. ELECTRICAL ............................................................................................................................. 4
3.5. PHYSICAL.................................................................................................................................. 5
4. STATUS INDICATORS ....................................................................................................................... 5
4.1. MODULE STATUS LEDS........................................................................................................... 5
4.2. DOT-MATRIX DISPLAY ............................................................................................................. 5
4.2.1. Audio Level Bar Graphs .................................................................................................. 5
5. CARD EDGE CONTROLS .................................................................................................................. 6
5.1. AUDIO LEVELS, HEADROOM, CLIPPING AND THE BAR GRAPHS ..................................... 6
5.1.1. Input Audio Level Calibration .......................................................................................... 6
6. JUMPERS............................................................................................................................................ 7
6.1. SELECTING WHETHER LOCAL FAULTS WILL BE MONITORED
BY THE GLOBAL FRAME STATUS.......................................................................................... 7
6.2. SETTING THE COARSE ANALOG INPUT GAIN RANGE........................................................ 8
6.3. CONFIGURING THE MODULE FOR FIRMWARE UPGRADES ............................................... 8
Figures
Figure 1: 7720ADC-A4 Block Diagram .................................................................................................................1
Figure 2: 7720ADC-A4 Rear Panel .......................................................................................................................2
Figure 3: Bar Graph Displays ................................................................................................................................5
Figure 4: Location of Jumpers...............................................................................................................................7
Tables
Table 1: Bar Graph Levels ....................................................................................................................................6

7700 MultiFrame Manual
7720ADC-A4 Analog Audio to AES Converter
Revision 1.1
REVISION HISTORY
REVISION DESCRIPTION DATE
1.0 Original Version Oct 01
1.1 Added Warning for Balanced Audio Shielding Aug 03
Information contained in this manual is believed to be accurate and reliable. However, Evertz assumes no responsibility for the use thereof nor for
the rights of third parties, which may be effected in any way by the use thereof. Any representations in this document concerning performance of
Evertz products are for informational use only and are not warranties of future performance, either express or implied. The only warranty offered by
Evertz in relation to this product is the Evertz standard limited warranty, stated in the sales contract or order confirmation form.
Although every attempt has been made to accurately describe the features, installation and operation of this product in this manual, no warranty is
granted nor liability assumed in relation to any errors or omissions unless specifically undertaken in the Evertz sales contract or order confirmation.
Information contained in this manual is periodically updated and changes will be incorporated into subsequent editions. If you encounter an error,
please notify Evertz Customer Service department. Evertz reserves the right, without notice or liability, to make changes in equipment design or
specifications.

7700 MultiFrame Manual
7720ADC-A4 Analog Audio to AES Converter
Revision 1.1 7720ADC-A4-1
1. OVERVIEW
The 7720ADC-A4 is a high-quality, 24-bit, analog to digital audio converter that provides conversion of 4
balanced analog audio channels to 2 AES channels.
The sampling clock may free run at 48KHz or may be locked to a DARS (Digital Audio Reference Signal)
reference or composite video reference. The 7720ADC-A4 will autodetect the presence and type of
reference signal. Level control is provided via a card edge toggle switch and the level can be read out
from a card edge display for convenience. The full scale digital signal can be calibrated to accommodate
peak levels ranging from 8dBu to 27dBu with 0.5 dB steps.
The audio ADC features a card edge VU meter for quick confidence monitoring. Four separate volume
indicators are provided via bargraphs for quick validation of audio program material.
Features
•Auto detect composite video or DARS on the reference input – unterminated for easy external loop
through
•24-bit, high-quality analog to digital audio conversion
•Support for 4 channels of audio
•Analog audio input levels are adjustable. Jumpers set coarse input levels, fine input levels are set by
software control using card edge control and a LED display
•0dBFS programmable from 8dBu to 27dBu in 0.5dBu steps
•A card edge display provides a 4 channel bargraph type volume indicator display for confidence
monitoring
Dual
ADC
DARS
Composite
Reference
VCXO
PLL
Control
Dual
ADC
Level Control
-18dBu
DARS or
Composite Video
Reference
2 Analog
Balanced Inputs
(ch1,ch2)
2 Analog
Balanced Inputs
(ch3,ch4)
Card Edge Level Display
Module
Status
AES
Formatter
Cable
Driver
AES
Formatter
Cable
Driver
AES Outputs
(SMPTE 276M)
1
2
Figure 1: 7720ADC-A4 Block Diagram

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2. INSTALLATION
The 7720ADC-A4 modules each come with a companion rear plate that has 3 BNC connectors and two 6
pin terminal strips. For information on mounting the rear plate and inserting the module into the frame see
section 3 of the 7700FR chapter.
Figure 2: 7720ADC-A4 Rear Panel

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7720ADC-A4 Analog Audio to AES Converter
Revision 1.1 7720ADC-A4-3
2.1. ANALOG AUDIO CONNECTIONS
The 7720ADC-A4 has two 6 pin terminal blocks containing balanced analog audio input. The audio cables
can be secured into the removable portion of the terminal strips using a small screwdriver. The removable
part of the terminal strip is then inserted into the rear panel.
!
Caution should be exercised when connecting cable shield to the “shield ground” as
this input has only a limited tolerance for any arising ground loop currents.
When using 7720ADC-A4, the shield should be connected at one end of the cable,
only. Which end of the cable shield should be grounded, source or destination, is a
matter of local practice / preference. For an authoritative guide to cable shield
connections, please refer to Rane Note 151 (“Grounding and Shielding Audio
Devices”, http://www.rane.com/pdf/note151.pdf). For the purposes of interpreting this
very thorough application note, be advised that 7720ADC-A4 connector pin “shield
ground” is internally connected to “signal ground” (not “chassis ground”).
Shield ground loops currents may arise, if the source equipment “shield ground”
potential is significantly different from 7720ADC-A4 local power ground and the shield
is grounded at both ends. The card can tolerate about 0.5A of any resulting ground
loop current. Exceeding this limit risks causing catastrophic failure of the card.
2.2. AES AUDIO CONNECTIONS
The 7720ADC-A4 has two BNC connectors for outputting unbalanced AES signals compatible with the
SMPTE 276M standard. The AES IN 1 output will come from the Analog Audio 1 and 2 inputs and the
AES IN 2 output will come from the Analog Audio 3 and 4 inputs.
2.3. AES REFERENCE CONNECTIONS
REF IN Composite video or DARS reference input. This input is high impedance and must be
terminated externally.

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3. SPECIFICATIONS
3.1. ANALOG AUDIO INPUT:
Number of Inputs: 4
Type: Balanced analog audio
Connector: Removable terminal strip
Input Impedance: 10k Ωminimum (differential)
Sampling Frequency: 48kHz synchronous locked to reference
48 kHz ± 50 ppm free run if no reference
Signal Level: 0dB FS = 24dBu or 18dBu (jumper selectable)
Level Control Range: ± 10dB
Frequency Response: ± 0.1dB (20Hz to 20kHz)
SNR: 100dB with input at -0.5dBFS
THD+N: < 0.001% (>100dB) @ 20Hz to 20kHz, -0.5 dB FS
CMRR: >100dB @ 1kHz
3.2. AES AUDIO OUTPUTS
Number of Outputs: 2
Standard: SMPTE 276M, unbalanced AES
Connectors: BNC per IEC 169-8
Sampling Rate: 48 kHz, synchronous with reference if applied
Impedance: 75 Ωunbalanced
3.3. REFERENCE INPUT
Standard: NTSC (SMPTE 170M), PAL (ITU624-4)
DARS
Number of Inputs: 1
Connector: BNC per IEC 169-8
Signal Level:
Video: Max: 2Vp-p video
Min: Sync level 150mV
DARS: SMPTE 276M, 1Vp-p
Frequency Lock Range: ±100ppm from nominal
Input Impedance: High impedance – external termination required.
Return Loss: >25dB to 10MHz (with external 75Ωtermination)
3.4. ELECTRICAL
Voltage: + 12VDC
Power: 10 watts
EMI/RFI: Complies with FCC Part 15, class A and EU EMC directive.

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Revision 1.1 7720ADC-A4-5
3.5. PHYSICAL
7700 or 7701 frame mounting:
Number of slots: 1
Stand Alone Enclosure:
Dimensions: 14 “ L x 4.5 “ W x 1.9 “ H
(355 mm L x 114 mm W x 48 mm H)
Weight: approx. 1.5 lbs. (0.7 Kg)
4. STATUS INDICATORS
The 7720ADC-A4 has 2 LED Status indicators and a 4 digit alphanumeric display on the front card edge to
show operational status of the card at a glance. The card edge pushbutton is used to select various
displays on the alphanumeric display. The location of the status LEDs is shown in Figure 4.
4.1. MODULE STATUS LEDS
MODULE OK This Green LED will be On when the module is operating properly
LOCAL FAULT This Red LED makes it easy to identify one module in a frame that is missing an
essential input or has another fault.
The LED will blink on and off if the microprocessor is not running.
The LED will be on solid when there is a fault in the module power supply.
4.2. DOT-MATRIX DISPLAY
Additional signal and status monitoring is provided via the 4-digit dot-matrix display located on the card
edge. The rotary switch position determines what is displayed on the dot matrix display. When it is set to
position 0, the input audio levels are shown using bar graphs on the display. Pressing the toggle switch
up when the rotary switch is a position 0 will orient the display vertically; pressing the toggle switch down
will orient the display horizontally. When it is set to 1 to 4 the gain level for each of the channels will be
displayed, and can be set using the toggle switch (see section 5.1.1).
4.2.1. Audio Level Bar Graphs
When the rotary switch is set to position 0, each section of the dot matrix display shows a bar graph
representation of the level for one of the audio channels. Channel 1 is shown on the left (top) section and
channel 4 is shown on the right (bottom) section. Each section of the display is comprised of a 5 x 5 array
of dots. Diagonal rows of dots represent one of 9 different signal levels as shown below.
Level 3
Level 5
Level 4
Level 6
Level 7
Level 9
Level 8
Level 1
Level 2
Figure 3: Bar Graph Displays
The signal levels shown in Table 1 are nominally in dBFS units. Table 1 also shows the levels in dBu
when the gain is set to 0 dB (see section 5.1.1) and the level jumpers are set so that 24 dBu = 0 dBFS

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(see section 6.2). The ballistics of the bar graph displays follow the AES/EBU guidelines and have the
attack time constant set to 0 seconds, and the decay time constant set to 1.5 seconds / 20 dB.
Bar Graph Level dBFS dBu
Level 1 -60 -36
Level 2 -36 -12
Level 3 -30 -6
Level 4 -24 0
Level 5 -21 3
Level 6 -18 6
Level 7 -15 9
Level 8 -12 12
Level 9 -6 18
Table 1: Bar Graph Levels
5. CARD EDGE CONTROLS
On the card edge there is a toggle switch and a ten position rotary switch that are used to choose what will
be displayed on the dot matrix display, and to set the gain for each of the analog channels.
5.1. AUDIO LEVELS, HEADROOM, CLIPPING AND THE BAR GRAPHS
This section contains notes to understand how the 7720ADC-A4 relates analog audio levels, digital audio
levels, and the displayed bar graph levels.
Before you can calibrate the audio analog to digital converter, you must know a couple of system issues
specific to your application. What is your analog reference level and how much headroom do you want to
have in the digital audio signal? By adding these two values together, you will get the analog input level
that will just begin to saturate the digital word (This is the highest level that can be represented without
distortion with the digital numbers). This level is called 0dB FS (FS stands for "full scale"). For instance, if
your analog program reference level is 4dBu and you want 20dB of headroom in the "digital world", then
0dB FS will correspond to an analog level of 24dBu. Once the audio input level is calibrated, when you
apply a 4dBu analog signal, the digital level will be –20dB FS.
The AES output audio and the bargraphs are all based on the digital quantized signal. The card edge
bargraph display is scaled to 0dB FS.
5.1.1. Input Audio Level Calibration
The analog audio input circuitry has two gain control stages before the audio is digitized. Eight Jumpers
located near the rear of the 7720ADC-A4 module are used to set a coarse gain level. (See Figure 4 for
location of jumpers) When the jumpers are not installed, the input range is optimized for when peak audio
levels up to 24dBu. When the jumpers are installed, best performance is achieved when input peak levels
are below 18dBu.
The toggle switch and rotary switch on the card edge of the 7720ADC-A4 allow independent ±10dB audio
level control of all four channels. To set the gain of one of the audio channels, select the channel number
using the rotary switch. The corresponding channel number will be displayed on the dot matrix display.

7700 MultiFrame Manual
7720ADC-A4 Analog Audio to AES Converter
Revision 1.1 7720ADC-A4-7
Alternately, the current gain setting for the selected channel will be displayed. To increase the gain, press
the toggle switch in the up (toward the dot matrix display) position. To decrease the gain, press the toggle
switch down. The gain is adjusted in 0.5 dBu steps, and will be displayed on the dot matrix display. To
adjust the gain for other channels first select the channel using the rotary switch then adjust the level
using to toggle switch. When you are finished setting the gain levels, return the rotary switch to position 0.
The following is an example calibration procedure:
1. Take your analog program reference level and add the amount of desired headroom in the digital
signal (SMPTE standard is 20dB). If this number is greater than 18dBu, then remove the 8 jumpers
near the rear of the 7720ADC-A4 module. If the number is less than 18dBu, then install the 8 jumpers.
(see Figure 4 for location of jumpers)
2. Apply an analog audio signal of the level calculated above.
3. Monitor the output AES audio with appropriate level measuring equipment.
4. Adjust the card edge level controls (described above) so that the digital level just starts to clip.
5. Verify the settings by applying program reference level audio signals. The bargraphs should read a
level that is below 0dB FS by the desired headroom level.
6. JUMPERS
MODULE STATUS
EVERTZ
(A) 7735AI
SFF POWER+12V
Run
Upg
J28
J10
J1
FRAME STATUS
ON OFF
GND
J13
J12
J6
J30
Figure 4: Location of Jumpers
6.1. SELECTING WHETHER LOCAL FAULTS WILL BE MONITORED
BY THE GLOBAL FRAME STATUS
FRAME STATUS The FRAME STATUS jumper J1 located at the front of the module determines
whether local faults (as shown by the Local Fault indicator) will be connected to the
7700FR frame's global status bus.
To monitor faults on this module with the frame status indicators (on the Power
Supply FRAME STATUS LED's and on the Frame's Fault Tally output) install this
jumper in the On position. (Default)

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When this jumper is installed in the Off position, local faults on this module will not
be monitored.
6.2. SETTING THE COARSE ANALOG INPUT GAIN RANGE
J13, J12, J6, J30 Eight Jumpers located near the rear of the 7720ADC-A4 module are used to set a
coarse gain level.
When the jumpers are not installed (or installed so that only one side is connected),
the input range is optimized for when peak audio levels reach up to 24dBu. (Default)
When the jumpers are installed, best performance is achieved when input peak
levels are below 18dBu.
6.3. CONFIGURING THE MODULE FOR FIRMWARE UPGRADES
UPGRADE The UPGRADE jumper J28 located at the front of the module is used when firmware
upgrades are being done to the module. For normal operation it should be installed
in the RUN position. See the Upgrading Firmware chapter in the front of the manual
binder for more information.
To upgrade the firmware in the module unit pull it out of the frame. Move Jumper
J28 into the UPGRD position. Install the Upgrade cable provided (located in the
vinyl pouch in the front of this manual binder) onto header J10 at the card edge.
Re-install the module into the frame. Run the upgrade as described in the
Upgrading Firmware chapter in the front of the manual binder. Once the upgrade is
completed, remove the module from the frame, move J28 into the RUN position,
remove the upgrade cable and re-install the module. The module is now ready for
normal operation.