evertz 7700 Series User manual

7700 MultiFrame Manual
7720DAC-A4 AES to Analog Audio Converter
1. OVERVIEW......................................................................................................................................... 1
2. INSTALLATION.................................................................................................................................. 2
2.1. AES AUDIO CONNECTIONS.................................................................................................... 3
2.2. ANALOG AUDIO CONNECTIONS ........................................................................................... 3
3. SPECIFICATIONS.............................................................................................................................. 4
3.1. UNBALANCED AES AUDIO INPUTS (7720DAC-A4).............................................................. 4
3.2. BALANCED AES AUDIO INPUTS (7720DAC-A4-B) ............................................................... 4
3.3. ANALOG AUDIO OUTPUT: ......................................................................................................5
3.4. ELECTRICAL ............................................................................................................................ 5
3.5. PHYSICAL................................................................................................................................. 5
4. STATUS INDICATORS ...................................................................................................................... 5
4.1. MODULE STATUS LEDS.......................................................................................................... 5
4.2. CHANNEL STATUS INDICATOR LEDS................................................................................... 6
4.3. DOT-MATRIX DISPLAY ............................................................................................................ 6
4.3.1. Audio Level Bar Graphs .................................................................................................6
4.3.2. Detected Sample Rate Display ...................................................................................... 7
4.3.3. Detected Numerical Peak DBFS Levels Display............................................................ 7
5. CARD EDGE CONTROLS ................................................................................................................. 8
5.1. AUDIO LEVELS, HEADROOM, CLIPPING AND THE BAR GRAPHS .................................... 8
5.1.1. Audio Level Calibration ..................................................................................................8
6. JUMPERS........................................................................................................................................... 9
6.1. SELECTING WHETHER LOCAL FAULTS WILL BE MONITORED
BY THE GLOBAL FRAME STATUS......................................................................................... 9
6.2. CONFIGURING THE MODULE FOR FIRMWARE UPGRADES ..............................................9
Figures
Figure 1: 7720DAC-A4 Block Diagram ............................................................................................................... 2
Figure 2: 7720DAC-A4-B Block Diagram............................................................................................................ 2
Figure 3: 7720DAC-A4 Rear Panels ................................................................................................................... 3
Figure 4: Bar Graph Displays .............................................................................................................................. 6
Figure 5: Location of Jumpers............................................................................................................................. 9
Tables
Table 1: Card Edge CHANNEL Status LEDs...................................................................................................... 6
Table 2: Bar Graph Levels .................................................................................................................................. 7
Table 3: Sample Rate Display............................................................................................................................. 7
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7720DAC-A4 AES to Analog Audio Converter
REVISION HISTORY
REVISION DESCRIPTION DATE
1.0 Original Version Apr 02
1.1 Added section 4.2 on channel status LEDS Apr 02
1.2 Added warning on connecting shields for balanced audio connections 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.
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7720DAC-A4 AES to Analog Audio Converter
1. OVERVIEW
The 7720DAC-A4 is a high-quality, 24-bit, digital to analog audio converter that provides conversion of 2
AES channels to 4 balanced analog audio channels.
The incoming sample rate may be either 48 kHz or 44.1 kHz, both within ±100 ppm limits. The 7720DAC-
A4 will autodetect the sample rate. Level control is provided via a card edge rotary knob and toggle switch
and the level can be read out from a card edge display for convenience. The full scale analog signal can
be calibrated to accommodate peak levels ranging from +12 dBu to +25 dBu with 0.1 dB steps.
The audio DAC features a card edge PPM meter for quick confidence monitoring. Four separate peak
volume indicators are provided via bargraphs for quick validation of audio program material.
Features
24-bit, high-quality digital to analog audio conversion•
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Support for 4 channels of audio
Separate versions available for balanced or unbalanced AES
AES channels 1 & 2 are fully independent
48 kHz and 44.1 kHz sample rates with automatic detection
Automatic input AES equalizer for both coax and twisted pair inputs
Low impedance (66 ohm) balanced output drive
Can drive 600 ohm loads up to +24 dBm
Output short protection, inaudible on adjacent channels
Analog audio output levels are set by software control using card edge control and an LED display
0 dBFS programmable from +12 dBu to +25 dBu in 0.1 dB steps with hi-Z loads
0 dBFS programmable from +12 dBm to +24 dBm in 0.1 dB steps with 600 ohm loads
A card edge display provides a 4 channel bargraph type peak volume indicator display for confidence
monitoring
To help with level calibration, the display can show received digital peak levels for each channel as
numerical dBFS values. It is accurate between 0 and -80 dBFS with 1 dB resolution, updated once a
second.
High jitter immunity
AES 1
Dual
DAC
Dual
DAC
AES
Decoder
AES 2
AES
Decoder
Level Control
2 Analog
Balanced Outputs
(ch1,ch2)
2 Analog
Balanced Outputs
(ch3,ch4)
CONTROL/
INDICATION
LOCAL
CONTROL Module
Status
AES Inputs
(SMPTE 276M)
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7720DAC-A4 AES to Analog Audio Converter
Figure 1: 7720DAC-A4 Block Diagram
AES 1
Dual
DAC
Dual
DAC
AES
Decoder
AES 2
AES
Decoder
Level Control
2 Analog
Balanced Outputs
(ch1,ch2)
2 Analog
Balanced Outputs
(ch3,ch4)
AES Inputs
(AES3-1992)
CONTROL/
INDICATION
LOCAL
CONTROL Module
Status
Figure 2: 7720DAC-A4-B Block Diagram
2. INSTALLATION
The 7720DAC-A4 modules each come with a companion rear plate that has 2 BNC connectors and two 6
pin terminal strips. The 7720DAC-A4-B modules convert balanced AES audio and each come with a
companion rear plate that has 2 3 pin terminal strips 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.
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7720DAC-A4 AES to Analog Audio Converter
Figure 3: 7720DAC-A4 Rear Panels
2.1. AES AUDIO CONNECTIONS
The 7720DAC-A4 converts unbalanced AES audio and has two BNC connectors for inputting unbalanced
AES signals compatible with the SMPTE 276M standard. The 7720DAC-A4-B converts balanced AES
audio and has two 3 pin terminal strips for inputting balanced AES signals compatible with the AES3-1992
standard. The input 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.
2.2. ANALOG AUDIO CONNECTIONS
The 7720DAC-A4 has two 6 pin terminal blocks containing balanced analog audio that has been
converted from the input AES audio. The output 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. The left/right channels from the AES IN 1 input will come out the Analog Audio 1 and 2
outputs respectively. The left/right channels from the AES IN 2 input will come out the Analog Audio 3 and
4 outputs respectively.
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"
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 7720DAC-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.
3. SPECIFICATIONS
3.1. UNBALANCED AES AUDIO INPUTS (7720DAC-A4)
Number of Inputs: 2
Standard: SMPTE 276M, unbalanced AES
Connectors: BNC per IEC 169-8
Signal Level: 0.1 to 2.5 Vp-p
Equalization: >1000m @ 48kHz with 1 Vp-p drive and Belden 8281 or equivalent coax cable
Resolution: 24 bits
Sample Rate: 44.1, 48 kHz; ±100 ppm
(other rates between 42 - 50 kHz will remain audible but somewhat distorted)
Input Impedance: 75 Ω, AC-coupled
Return Loss: < 25 dB, 0.1 - 6.0 MHz
BNC Grounding: AC-coupled (for 60 Hz ground loop current protection)
3.2. BALANCED AES AUDIO INPUTS (7720DAC-A4-B)
Number of Inputs: 2
Standard: AES3-1992, balanced AES
Connectors: 3 pin removable terminal strip
Signal Level: 0.2 to 10.0 Vp-p
Equalization: >400m @ 48kHz with 2 to 10 Vp-p drive and Belden 1800B or equivalent shielded
twisted pair cable
Resolution: 24 bits
Sample Rate: 44.1, 48 kHz; ±100 ppm
(other rates between 42 - 50 kHz will remain audible but somewhat distorted)
Input Impedance: 110 Ω±10%, transformer coupled
Shield Grounding: AC-coupled (for 60 Hz ground loop current protection)
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3.3. ANALOG AUDIO OUTPUT:
Number of Outputs: 4
Type: Balanced analog audio
Connector: two 6 pin removable terminal strips
Output Impedance: 66 Ω
Signal Level: 0dB FS => +12 to +25 dBu into 10 K ohm load (user settable)
0dB FS => +12 to +24 dBu into 600 ohm load
Frequency Response: < ±0.05dB (20Hz to 20kHz)
Dynamic Range: 24 bits
THD+N: < -100dB RMS @ 20Hz to 20kHz, with 24dBu output, unweighted
SNR: > 110dB RMS (20Hz to 20kHz), unweighted
Crosstalk Isolation: > 110dB RMS (20Hz to 20kHz), unweighted
Inter-Channel Phase
Error: < ± 1° (20Hz to 20kHz)
Digital to Analog Delay:0.95m Sec
3.4. ELECTRICAL
Voltage: + 12VDC
Power: 12 watts
EMI/RFI: Complies with FCC Part 15, class A and EU EMC directive.
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 7720DAC-A4 has 2 LED modules status indicators, 8 LED audio channels 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 5.
4.1. MODULE STATUS LEDS
MODULE OK This Green LED will be On when the module is operating properly
LOCAL FAULT The LED will be on solid when there is a fault in the module power supply or its
digital electronics are failing their self-test.
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4.2. CHANNEL STATUS INDICATOR LEDS
On the card edge, each channel has two indicator LEDs: one red (bottom side of the card) and one green
(top side of the card). The group of LEDs closest to the toggle switch represents CHANNEL 1 (left channel
in AES input 1), followed by LEDs for CHANNEL 2, 3, and 4. The table below summarizes their meaning:
Green LED Red LED Meaning
Off Solid
RED
Input AES is not recognized:
There is no input, or cable length is too long, or sample rate is outside of 42-50
kHz range
The analog outputs will be muted
Flickering
GREEN
Flashing
And flickering
RED
Input AES is between 42-50 kHz but the signal is getting too weak to recognize
The analog output audio will show a varying degree of distortion
Solid
GREEN
Flashing
RED
Input AES is between 42-50 kHz but it is outside of both 44.1 kHz (±100 ppm)
and 48 kHz (±100 ppm) specs
The analog output audio should be intelligible but will show a varying degree of
distortion
Solid
GREEN
Off valid AES input
Table 1: Card Edge CHANNEL Status LEDs
4.3. 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 peak levels are shown using bar graphs on the display. Pressing the toggle
switch up when the rotary switch is at 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 peak level corresponding to 0 dBFS
input for each of the channels will be displayed, and can be set using the toggle switch (see section 5.1.1).
When the rotary switch is at position 5, the display will show lock status and the detected sample rates for
each AES input (see section 4.3.2). When the rotary switch is at position 6, the display will show the
numerical values of peak levels found in each input channel (see section 4.3.3).
4.3.1. 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 peak 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 peak levels as shown
below.
Level 3 Level 5Level 4 Level 6 Level 7 Level 9Level 8Level 1 Level 2
Figure 4: Bar Graph Displays
The signal levels shown in Table 2 are nominally in dBFS units. Table 2 also shows the peak levels in dBu
when the peak level is set so that 24 dBu = 0 dBFS (see section 5.1.1). The ballistics of the bar graph
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display 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 2: Bar Graph Levels
4.3.2. Detected Sample Rate Display
When the rotary switch is set to 5, the display will show lock status and the detected sample rates for each
AES input. The left (or top) two digits will show the rate of AES 1, and the right (or bottom) two digits will
show the rate of AES 2. Table 3 summarizes the meaning of the display content:
Display Meaning
XX
input AES is not recognized:
there is no input, or
cable length is too long, or
sample rate is outside of 42 - 50 kHz range
the analog output audio will be muted
44
(flashing)
Input sample rate is between 42 - 46 kHz and it is either outside of 44.1 kHz (±100
ppm) spec or the signal is getting too weak to recognize. The analog output audio
should be intelligible but will show a varying degree of distortion
48
(flashing)
Input is between 46 - 50 kHz and it is either outside of 48 kHz (±100 ppm) spec or the
signal is getting too weak to recognize. The analog output audio should be intelligible
but will show a varying degree of distortion
44 valid 44.1 kHz (±100 ppm) input
48 valid 48 kHz (±100 ppm) input
Table 3: Sample Rate Display
4.3.3. Detected Numerical Peak DBFS Levels Display
When the rotary switch is set to 6, the display will show the numerical values of peak levels found in each
input channel. By using the toggle switch, the display can be changed to display any 1 of the 4 input audio
channels. Each time, the display will show the channel number, followed by the “-“ (minus) sign, and a 2
digit number representing the detected peak level in dBFS.
E.g.: if the display reads “2-13”, then it means that channel 2 (the right channel in AES 1) had peak levels
reaching -13 dBFS.
If the input doesn’t lock properly, the peaks will read as “??”.
This measurement is updated about once a second and is accurate to within 1 dB from 0 down to
-80 dBFS. Below –80 dBFS, the displayed value is only approximate.
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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 7720DAC-A4 relates analog audio levels, digital audio
levels, and the displayed bar graph levels.
Before you can calibrate the audio digital to analog converter, you must know a couple of system issues
specific to your application. What is your customary analog reference level and how much headroom do
you have in the digital audio signal? By adding these two values together, you will get the analog peak
output level that corresponds to saturated digital word (i.e.: 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 (also known as “standard operating level” or SOL) is 4dBu
and you have 20dB of headroom in the "digital world", then 0dB FS should correspond to an analog level
of 24dBu. Once the audio output level is calibrated, when you apply a –20dBFS digital signal, the analog
level will be4dBu.
The AES input 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. Audio Level Calibration
The toggle switch and rotary switch on the card edge of the 7720DAC-A4 allow independent audio level
control of all four channels. To set the level 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.
Alternately, the current level setting for the selected channel will be displayed. This level is shown in dBu
units. To increase the level, press the toggle switch in the up (toward the dot matrix display) position. To
decrease the level, press the toggle switch down. The level is adjusted in 0.1 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 levels, return
the rotary switch to position 0. The calibrated levels will be saved and recalled after a power loss.
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6. JUMPERS
MODULE STATUS
EVERTZ
(A) 7720DAC-A4
SFF POWER+12V
Run
Upg
J10
J1
J2
FRAME STATUS
ON OFF
GND
CHANNEL 1
CHANNEL 2
CHANNEL 3
CHANNEL 4
COM
Figure 5: Location of Jumpers
6.1. SELECTING WHETHER LOCAL FAULTS WILL BE MONITORED
BY THE GLOBAL FRAME STATUS
FRAME STATUS The FRAME STATUS jumper J2 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)
When this jumper is installed in the Off position, local faults on this module will not
be monitored.
6.2. CONFIGURING THE MODULE FOR FIRMWARE UPGRADES
UPGRADE The UPGRADE jumper J10 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 binder
for more information.
To upgrade the firmware in the module unit pull it out of the frame. Move Jumper
J10 into the UPGRD position. Install the Upgrade cable provided (located in the
vinyl pouch in the front of this manual binder) onto header J1 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 binder. Once the upgrade is completed, remove
the module from the frame, move J10 into the RUN position, remove the upgrade
cable and re-install the module. The module is now ready for normal operation.
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