Freeway input cards
Pro-Bel Ltd
Contents
1
Introduction
3
2
Installation and configuration
5
2.1
2.2
2.3
2.4
2.5
2.6
Removal and replacement of modules
Setting the level switch
Setting the Higher Destination Decode switch
LED indications
The Freeway control card
Resetting the module
5
6
7
8
8
8
3
Serial digital video
3.1
3.2
3.3
3.4
Introduction
Theory of operation
Expanding digital video systems
Specification
4
Analogue video
4.1
4.2
4.3
4.4
4.5
4.6
Introduction
Theory of operation
Setting inputs for DC coupled or restored operation
Base card cable connection
Expanding analogue video systems
Specification
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Freeway input cards
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Analogue and AES digital audio
5.1
5.7
5.8
5.9
Introduction
5.1.1 AES digital audio
5.1.2 Analogue audio
Theory of operation
5.2.1 AES digital audio
5.2.2 Analogue audio
4945 AES module installation and configuration
5.3.1 LED indications
5.3.2 Setting Mode 1
5.3.3 Setting Mode 2
5.3.4 Setting Mode 3
Rear panel connections for AES
4942 AES reference generator card
5.5.1 Theory of operation
5.5.2 Installation and configuration
4745 Analogue Audio module installation and configuration
5.6.1 LED indications
5.6.2 ADC submodule - 4741
5.6.3 Setting noise gate and mute jumpers
Rear panel connections for analogue audio
Expanding audio systems
Specification
6
Problem solving
45
7
Optional hardware and spare parts
47
5.2
5.3
5.4
5.5
5.6
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Technical manual
Introduction
The Freeway series of routing switchers addresses the needs for installations
requiring ‘square’ router configurations. While this fulfils most applications, there are
still instances requiring ‘non-square’ configurations such as monitoring switchers. In
order to satisfy these requirements, a further set of modules offering sixteen input
channels is provided as part of the Freeway family of routing switchers.
Freeway input cards are available in four signal formats; serial digital video,
analogue video, AES digital audio and stereo analogue audio. These modules permit
Freeway 32, 64 and 128 router levels to be expanded within standard 3U and 6U
frames. Using this approach, it is possible to build routers up to 64x16, 64x32 and
64x48 for both analogue and digital video levels, and 128x16, 128x32 through to
128x112 for the audio levels in steps of sixteen inputs at a time.
As with all other Freeway signal cards, provision for housing a system controller,
either main or backup, has also been allowed for on these input modules. Freeway
control modules contain the system database. The Freeway Editor user guide details
how to programme or re-configure the database.
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Freeway input cards
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HU-Freeway Input Modules
Pro-Bel Ltd
Technical manual
2 Installation and configuration
This section provides general installation and configuration information common to
all of the Freeway input cards. Specific requirements relating to each signal type,
such as audio connector details are contained within the relevant sub-section of this
part of the technical manual. Details relating to operations specific to frames, such as
removal and replacement of doors and power supplies are contained within the
General Information section of the first part of this handbook.
n 2.1 Removal and replacement of modules
Freeway input cards can be removed from the frame and replaced, powered or unpowered, using the following procedure. When removing the bottom card from a
frame, it is necessary to remove the door before continuing. For removal purposes it
is advisable to remove any ribbon cables from the card edge first, then the cards.
·
release the ribbon cables by pushing the catches up on either end of the
connector as shown
·
lift up the card ejector on the module and gently pull the card out
Replacement is the reverse of above:
·
slide the card along the guide rail of the required slot, gently pushing it fully
home until it marries up with the connector on the motherboard
Catches
Side view
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Top view
Front view
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Freeway input cards
Pro-Bel Ltd
n 2.2 Setting the level switch
A Freeway router can comprise of up to eight levels. In order for these to be
independently controlled, each must have a different level address. By setting the
LEVEL address switch located on the front of each Freeway module, the control
system can identify each level and, where necessary, control it independently. It is
desirable in some applications, such as component or RGB routers, to provide
married switching across a number of levels. In these instances the LEVEL address
should be the same for each router card.
Levels addresses are set as follows:
SW 1
SW 2
SW 3
SW 4
Level No
0
0
0
0
1
1
0
0
0
2
0
1
0
0
3
1
1
0
0
4
0
0
1
0
5
1
0
1
0
6
0
1
1
0
7
1
1
1
0
8
A typical system might be arranged like this:
6
Level 1
Serial Digital Video
Level 2
Analogue Video
Level 3
AES Digital Audio
Level 4
Stereo Analogue Audio
Level 5
Timecode
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Technical manual
SW1
SW2
View from front of card:
0
1
Off
On
Higher Dest Decode
Off
0
1
On
switch up for Off
switch down for On
Level
Reset
switch
Control card
Hello
Green
LEDs
+5V
-5V
n 2.3 The Higher Dest Decode switch
The HIGHER DEST DECODE switch, located on the card edge adjacent to the LEVEL
address switch, normally identifies the range of destinations being provided from
each card on a level by level basis, permitting the module to respond to switch
commands issued by the controller.
Freeway input cards, however, are not fitted with crosspoints and therefore do not
have any controllable destinations. In this case the HIGHER DEST DECODE switch is
redundant, and any switch settings are ignored by the control circuitry.
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Freeway input cards
Pro-Bel Ltd
n 2.4 LED indications
Two of the three LEDs, located on the card edge, indicate that power is arriving to the
board. Freeway routers operate from two rails only, these are +5V and -5V. Where
others are required, they are derived on the Freeway cards themselves.
The third LED is labelled ‘HELLO’. This is useful in determining whether the control
system has spoken to a particular board and, specifically, will tell you if the LEVEL
and HIGHER DEST DECODE switches are set correctly.
When the control system sends a command, for example in response to a button
push, the appropriate part of the router responds, depending on how the board
configuration switches are set.
When a board receives a command on which it should act, it ‘winks’ the ‘HELLO’ LED.
Meaning, ‘Hello, I’ve just received a command that’s relevant according to my
programmed place in the scheme of things.’
n 2.5 The Freeway control card
Central to the operation of any Freeway routing system is the control card. The card,
type 2440, is a sub-module which may be fitted to any one of the router cards within
the system and is used to provide control to the router and hold configuration data.
If required, two cards may be fitted on separate signal modules within a Freeway
system, providing main and backup operation in the event that one microprocessor
card should fail. Full details on configuring the control card are given in Section 6 of
the general information section o f this Manual.
Each Freeway module is fitted with the relevant header allowing it to be fitted with a
controller, therefore any of the Freeway input cards may or may not host a control
card.
n 2.6 Resetting the module
There are two RESET switches available to perform a hard reset of the Freeway
controller. One is located on the edge of the 2440 sub-module, while the other is on
the front edge of the host card. Pressing either has the same effect.
Initiating a hard reset is similar to powering down and powering up the control
frame. The controller re-boots and follows the usual power-up sequence. It should be
noted that any panels connected to the system will shut down, and then be restored
after initialisation is complete. It should also be noted that resetting the active
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Technical manual
controller in a dual control environment will cause the active and idle controllers to
changeover.
If no changes have been made to the database then no crosspoints will be changed.
Crosspoint settings may be affected if changes to the level type have been made
prior to the reset, as, during initialisation crosspoints are set according to the level
type defined for each level.
It is also advisable to perform a reset after database parameters have been changed
as certain operations only take effect after a reset, e.g. changing level type, panel
type, source overrides, and controllable destinations.
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Freeway input cards
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HU-Freeway Input Modules
Pro-Bel Ltd
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Technical manual
Serial digital video
This section details the operation and operational alignment of the serial digital
video input card (3945) for the Freeway series of routing switchers.
n 3.1 Introduction
Freeway serial digital video input modules, like the Freeway 32 and 64 variants,
automatically accommodate data rates between 140 and 360Mbit/s providing full
compatibility for all standard definition digital signal formats.
Each input is fitted with an adaptive cable equaliser, providing automatic
equalisation for up to 250m of good quality co-axial cable.
n 3.2 Theory of operation
Each of the 16 inputs presented to the input module are buffered using a
receiver/equaliser. These buffered signals are then passed to the card edge connector
allowing them to be bussed across other system modules to the main output card, or
cards.
A single ribbon cable fitted to each board determines the input range the card is
supplying to the router. The following table details the cable position required for
each of the available input ranges.
Inputs
Position
17 - 32
A to C
33 - 48
A to D
49 - 64
A to E
* Freeway input modules can not be fitted for inputs 1-16 as the first 16 sources will
be provided by the main router module.
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Freeway input cards
Pro-Bel Ltd
Input stage
On front edge
of board
SK4
Input 1
Input 16
16
Input
cable
equaliser
A
B
CH 1-4 (Not fitted)
C
Input
cable
equaliser
D
E
Automatically
compensates for
different lengths of
cable on inputs
16
PL6
CH 5-8
PL6
16
CH 9-12
PL6
16
CH 13-16
Expansion connectors
Internal block diagram
SW1
SW2
View from front of card:
0
1
Off
Off
0
1
On
Higher Dest Decode
On
Level
switch up for Off
switch down for On
A
C
D
E
Green
LEDs
12
Hello
+5V
-5V
HU-Freeway Input Modules
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Technical manual
n 3.3 Expanding digital video systems
Base Freeway 32 and 64 routers may be expanded, by the addition of Freeway
digital video input cards. It is necessary to fit the expansion module in the slot
adjacent to the base router card, or other expansion cards, before connecting the
ribbon cables across the front of the modules.
Freeway 32
The following diagram details the cable connections required for expanding the
Freeway 32 router from 16x16 to 32x16. With this range it is not possible to expand
beyond 32 inputs.
Freeway 32 expansion 16x16 to 32x16
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Freeway input cards
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Freeway 64 expansion
The following diagrams detail the cable connections required for expanding Freeway
64 routers, covering the expansion sizes shown in the following table.
Outputs
Inputs
16
32
48
16
S
32
ü
S
48
ü
ü
S
64
ü
ü
ü
64
S
Key
S - Indicates that these router sizes start with a standard Freeway 64 router card.
ü - Indicates router sizes that can be constructed using the Freeway input cards
with base router module
Care must be taken to ensure that the expansion cables are fitted in the correct
positions, and that the level and destination assign switches are correctly set, see
sections 2.2 and 2.3.
As the Input cards and Freeway 64 router cards interconnect in the same manner.
The complete range of possible digital video expansion scenarios can be shown in
three drawings.
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Technical manual
By referencing the following table, the module positions for each expanded router
and the figure detailing the correct interconnections can be found.
Expansion from
16x16 to
32x16 to
48x16 to
32x32 to
48x32 to
48x48 to
32x16
48x16
64x16
48x32
64x32
64x48
Cable as shown in Fig 1
Fig 2
Fig 3
Fig 2
Fig 3
Fig 3
Top slot (1)
3940
3940
3940
3940
3940
3940
(2)
3945
3945*
3945*
3940
3940
3940
3945*
3945*
3945*
3945*
3940
3945*
3945*
(3)
Bottom slot (4)
3945*
For the configurations where 3945 modules are fitted in slots 2, 3 or 4, the
connectors and cable assemblies labelled • , ‚ or ƒ in the relevant diagrams are
not required. This is applicable to expansion configurations for 32 inputs and above.
Figure 1: 32x16 Expansion
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Freeway input cards
Pro-Bel Ltd
Figure 2: 48 x16 or 48 x 32 Expansion
Figure 3: 64 x16, 64 x 32 or 64 x 48 Expansion
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Technical manual
n 3.4 Specification
The following specification refers to a single Freeway 16 channel serial digital video
input module.
n Inputs
Number and type:
16: Unbalanced NRZI coded serial data
Standard:
Serial EBU Tech 3267E. SMPTE 259M-ABCD
Input Impedance:
75W
Data rate:
140 to 360Mbit/s
Return loss:
>13dB 10MHz to 360MHz
Amplitude:
800mV p-p nominal
DC offset:
<5V
Equaliser:
Adaptive automatic for up to 250m cable (typ.
Belden 8281, PSF 1/2M or equivalent)
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Freeway input cards
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Technical manual
Analogue video
This section details the operation and operational alignment for the analogue video
input card (3745) for the Freeway series of routing switchers.
n 4.1 Introduction
Freeway analogue video input cards provide 16 channel expansion modules for use
with Freeway 32 and 64 routing systems.
The circuitry employed within these modules is, like the Freeway 32 and 64 router
cards, transparent to all encoded vertical interval data ensuring they are fully
compatible with sound in sync (SIS) signals.
n 4.2 Theory of operation
User selectable jumper links on the card enable each of the 16 inputs to be set for DC
coupled or restored operation. Each of these inputs are then buffered before being
passed to the card edge connector permitting them to be bussed to other system
modules such as the main output card, or cards.
A single ribbon cable and submodule , type 3741, fitted to each board determines
the input range the card is supplying for the router. The following table and diagram
details the cable position required for each input range. While these modules may be
used to expand any of the video routers in the Freeway family, it is important to
remember they only permit expansion to the maximum allowable size for the router
range, that is 32 for Freeway 32 and 64 for Freeway 64.
Input/ Output range*
Position
17 - 32
A to C
33 - 48
A to D
49 - 64
A to E
* Freeway input modules can not be fitted for inputs 1-16 as these are provided by
the main router module..
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Freeway input cards
Pro-Bel Ltd
n 4.3 Setting inputs for DC coupled or restored
In traditional television applications a DC restore function is nearly always
appropriate in order to remove DC variations between signals. Without this function,
switching between signals with different DC components may cause frame-roll due to
corruption of the sync field-block.
However in other applications, such as a wideband analogue router, the DC restore
function is definitely not appropriate. These include the routing of computer type
RGB graphics signals and medium bit rate telecom signals. In these cases a stable DC
path must be provided.
To cater for all circumstances, Freeway provides a user selectable input stage
offering DC restored, or DC coupled operation. Where DC coupled operation is
selected, all circuitry downstream of the input stage is DC coupled. This is selectable
on an input by input basis via PL9.
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DC COUPLE
DC COUPLE
DC REST
DC REST
DC COUPLE selection
DC RESTORE selection
PL9
n 4.4 Base card cable connection
In order to compensate for variations in frequency response which inevitably occur
with different numbers of sources connected to the signal ribbon on the front of
analogue video Freeway, special cables are supplied for use with Freeway router
cards. These should be installed as shown in either the Freeway 32 or 64 handbook
sections.
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Freeway input cards
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n 4.5 Expanding analogue video systems
Base Freeway 32 and 64 routers may be expanded, by the addition of Freeway
analogue video input cards. It is necessary to fit the expansion module in the slot
adjacent to the base router card, or other expansion cards, before connecting the
ribbon cables across the front of the modules.
The following diagrams detail the cable connections required for expanding both the
Freeway 32 router from 16x16 to 32x16 and for Freeway 64 routers covering the
expansion sizes shown in the following table.
Outputs
Inputs
16
32
48
16
S
32
ü
S
48
ü
ü
S
64
ü
ü
ü
64
S
Key
S - Indicates router sizes that can be achieved using standard Freeway modules
ü - Indicates router sizes that can be constructed using the Freeway input cards
Care should be taken to ensure that the expansion cables are fitted in the correct
positions, and that the level and destination assign switches are correctly set, see
sections 2.2 and 2.3.
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Freeway 32 expansion - 16x16 to 32x16
Freeway 64 expansion
As the Input cards and Freeway 64 router cards interconnect in the same manner, the
complete range of possible analogue video expansion scenarios can be shown in
three drawings, Figures 1 to 3. By referencing the table below, the module positions
for each expanded router and the drawing number detailing the correct
interconnections can be found.
From
16x16 to
32x16 to
48x16 to
32x32 to
48x32 to
48x48 to
32x16
48x16
64x16
48x32
64x32
64x48
Cable as
Fig 1
Fig 2
Fig 3
Fig 2
Fig 3
Fig 3
Top slot
3740
3740
3740
3740
3740
3740
3745
3745
3745
3740
3740
3740
3745
3745
3745
3745
3740
3745
3745
To
Bottom slot
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3745
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Freeway input cards
Pro-Bel Ltd
Figure 1: 32x32 Expansion
Figure 2: 48x16 or 48x32 expansion
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Technical manual
Figure 3: 64x16, 64x32 and 64x48 expansion
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Freeway input cards
Pro-Bel Ltd
n 4.6 Specification
The following specification refers to a single Freeway 16 channel analogue video
input module.
n Inputs
26
Number and type:
16: unbalanced on BRCS, 1V pk-pk amplitude
Impedance:
75W
Return loss:
Better than 40dB to 3.58MHz and 4.43MHz
Superimposed DC:
±1V max
Coupling:
DC or sync-tip restored
HU-Freeway Input Modules
Pro-Bel Ltd
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Technical manual
Analogue and AES digital audio
This section of the manual covers the installation, operation and operational
alignment of the digital (4945) and analogue (4745) audio input cards for the
Freeway series of routing switchers.
n 5.1 Introduction
Both the analogue and digital audio Freeway input cards provide 16 channel, input
expansion for the Freeway 32 and 128 audio router range. The addition of these
modules to the Freeway audio range enhances the overall system flexibility with the
ability to construct non square routers.
As with the rest of the Freeway analogue audio range, the input modules are fitted
with 20 bit ADC’s, converting the analogue signals presented to the module into the
digital domain for distribution inside the router. By utilising this same internal digital
architecture, the possibility of format-independent signal routing is retained. For
example, a 16x16 analogue audio router can be expanded using two digital input
cards providing a router with 32 digital and 16 analogue inputs and 16 analogue
outputs. This mixed format router permits digital sources to be routed to analogue
destinations saving on external audio converters.
5.1.1 AES digital audio
Freeway AES input modules may be set to operate in either synchronous or
asynchronous environments. When operated as a reframing router, Freeway
provides silent, ‘click-less’ switching between digital audio signals matching the
reference input at rates of 32 to 48kHz. Operation at rates between 22.05 and 96kHz
is supported by configuring the router in transparent mode. In order for these cards
to function correctly, other modules used to construct the router must be configured
for the same operating mode.
To promote flexible integration within any digital audio environment, modules may
be ordered for operation with balanced or unbalanced (75W) inputs.
Other features include:
·
reclocking and reframing architecture
·
optionally transparent for multi-standard 22.05-96kHz operation
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Freeway input cards
Pro-Bel Ltd
5.1.2 Analogue audio
The Freeway analogue audio input modules provide stereo operation, while
incorporating signal processing features useful to mixed mono/stereo environments,
like; left or right to both and channel swap. The transformerless input circuits are
level adjustable to a maximum of +24dBu.
n 5.2 Theory of operation
This section is divided into AES card and analogue card operation. However there is a
common element between the modules which is covered as a precursor to this.
Both input module types have been designed to use the common, digital, data bus
format shared by the Freeway analogue and digital audio router modules for
interconnection within the frame. This permits modules to be used within mixed
analogue/ digital routers.
5.2.1 AES digital audio
The AES card can be configured to operate either synchronously or asynchronously.
In order to be able to switch synchronously between digital audio sources, switches
must occur at AES frame boundaries. In order to achieve this, all signals presented to
the crosspoint bus must be co-timed, irrespective of their timing at the router input.
This re-timing process, known as re-framing, buffers each input and locks it to the
AES reference frequency. This will only work for signals of the same sample rate as
the reference input supplied to the frame.
While this method of operation is preferred, it does impose some operational
restrictions; First, only signals of the same sample rate as the reference input can be
re-framed. Secondly, The routing of signals with sample rates above 48kHz is
prohibited as the operating range of the reframing circuits prevent them from
working above this frequency. Finally, the internal data format within Freeway
means that the AES data has to be decoded - along with its channel status data, and
then is encoded back to AES before leaving the router.
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This process is not transparent to channel status data, and results in all of the AES
outputs being re-written with default channel status as follows;
·
Professional mode
·
Emphasis not indicated
·
Normal audio
·
Stereo
·
48kHz
Because of these restrictions, Freeway has three operational modes permitting it to
provide routing solutions for most digital audio applications. These modes are
known as Mode 1, 2 and 3. In all cases, while the input cards can be set to operate in
any of these modes, care must be taken to ensure that other cards within the audio
router are set to operate in the same mode. Details for setting the router cards can be
found in the relevant section of this handbook.
MODE 1 operation (Asynchronous 1)
In mode 1, the AES/EBU digital audio router is compatible with audio data from
22.05kHz to 96kHz. This mode enables the card to operate as a non-reclocking input
module providing transparent operation. Unless great care is taken to time align each
input to the router, this mode will result in audible glitches when switching, and is
incompatible with analogue I/O cards.
MODE 2 operation (Asynchronous 2)
In mode 2, the card operates in a manner in which it simply reclocks the received
audio data, in order to eliminate jitter, prior to switching. This mode, like mode 1
ensures transparency to all audio and channel status data. Mode 2 should be used
where transparency is paramount and where the digital audio signal is at any
recognised sample rate, with the exception of 22.05kHz and 96kHz. Unless great care
is taken to time each input to the router, this mode will, like mode 1, result in audible
glitches when switching and is also incompatible with analogue I/O cards.
Note that if the unit is configured in either mode 1 or mode 2, there is no compatibility
with the bus data-format of the analogue audio level.
MODE 3 operation
This is the preferred operational mode, resulting in click-less, synchronous AES
routing conforming to AES output timing. Channel status is ‘over-written’ with default
channel status into the AES output data stream. When operated in mode 3, the router
provides ‘click-less’ switching while integrating seamlessly with an analogue audio
router card in a ‘format-independent’ router.
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Balanced/ unbalanced operation
To promote flexible integration within any digital audio environment, systems are
available with either balanced (50 way ‘D’ type) or unbalanced (BNC) inputs and
outputs.
5.2.2 Analogue audio
The Freeway analogue audio input module employs high impedance, transformerless input stages providing operation with signal levels of up to +24dBu.
Input signals are treated as stereo and passed to the crosspoint bus. As such there is
no breakaway capability of left and right channels within these pairs. Advanced
signal handling within the Freeway analogue audio modules, however, provides the
switcher with the ability to ‘modify’ these stereo pairs. The audio modify functions
provided for inputs are;
·
channel swap
·
left to both
·
right to both,
In order to ensure that the internal bus is compatible with the digital signal modules,
all input signals arriving on the module are converted between the analogue and
digital domain using 20 bit converters. Once in the digital domain, these signals are
presented to the digital crosspoint bus, permitting them to be passed to other
Freeway audio routing modules.
5.3 4945 AES module installation and configuration
After setting the module as detailed in section 2 of this handbook, the card can now
be configured for its correct audio operating mode.
The AES router card does not require customer alignment and has no user-serviceable
adjustments beyond the card edge level / destination assign switches and the link
changes required to program the operational modes. As each channel is individually
configurable, a great deal of operational freedom is provided. However, beware of
mixed-mode operation as, the result of switching a signal in one mode to a
destination configured for another mode can result in high levels of noisy audio
modulation. This can have potentially damaging effects on downstream audio
equipment, especially loudspeakers (and ears!).
Remember, unless there is an overriding good reason to adopt another mode, mode 3
is the preferred operational mode for all channels.
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5.3.1 LED indications
Sixteen miniature LEDs appear at the front edge of the AES router card. These LEDs
are intended for input-status monitoring and may be used to determine whether
audio signal (or audio modulation) is present on each of the 16 inputs to the card.
The functionality of these LEDs change according to the operational mode the card is
set for.
In mode 1, the LEDs indicate the presence of audio input data, irrespective of audio
modulation.
In mode 2, because the reclocking circuits free-run, the LEDs remain permanently lit,
irrespective of the condition of the AES input signals and even if there is no input
present.
In mode3, the preferred operational mode, the LEDs are illuminated when audio
signal is present at the corresponding input. They will however be off when digital
silence is present as an input.
For diagnostic purposes, the AES router card is fitted with a dual-coloured LED. This
indicates whether or not the internal reference signal (TAES) is present. Green
indicates that it is, while flashing red indicates that it is not. Should the AES reference
be missing, this may cause audio disturbances during switching and must be
rectified. The reference present LED, although mounted towards the rear of the card,
can be seen when the board is housed within the frame simply by looking into the
frame from the front, between the installed modules.
5.3.2 Configuring mode 1
In order to set the card to operate in this mode, links on the input stages must be set
in the BPS (Bypass) position, as shown in the following diagram. (Note that when BPS
is selected, the position of the links for the RC/RF selectors, also in the input area is
irrelevant.) The operation of the circuit may be determined easily from examination
of the Freeway audio system diagram in Chapter 5.2 of this section.
BPS
HU-Freeway Input Modules
R/R
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Freeway input cards
Pro-Bel Ltd
5.3.3 Configuring mode 2
In this mode, the input data is reclocked by the input stage receiver, before being
passed to the crosspoint bus. The operation of the circuit may be determined from
examination of the Freeway audio system diagram in chapter 5.2 of this section. In
order to configure this mode, the links marked BPS/RR in the input stage area must
be set to the R/R position. (The R/R stands for Reclock or reframe). Next, the links
marked RC/RF must be set in the RC (i.e. Reclock) position. The position of these
links is illustrated below.
BPS
R/R
RC
RF
5.3.4 Configuring mode 3
In this mode the input stage works in a reframing mode, therefore the BPS/RR input
stage links must be set in the R/R position, while the links marked RC/RF must be set
to the RF (i.e. Reframe) position.
The operation of the circuit may be determined from examination of the Freeway
audio system diagram (Section 5.2). The position of each of these links on the 4945
card is illustrated in the following diagram.
However, once again, beware of setting the router for mixed mode operation; ideally
all channels should be configured the same way.
32
BPS
R/R
RC
RF
HU-Freeway Input Modules
Pro-Bel Ltd
Technical manual
n 5.4 Rear panel connections for AES
The AES input card uses a standard 16x16 Freeway audio router rear panel. While the
connector panel is fitted with two connectors, one for inputs and the other for
outputs, it is necessary in this instance to use only the input connector.
Refer to the diagram below for pinout details
1
50
1
50
Inputs
HU-Freeway Input Modules
Pin
Function
Pin
Function
1
Chassis
50
Chassis
34
1 Gnd
42
9 Gnd
18
1+
26
9+
2
1-
10
9-
3
2 Gnd
11
10 Gnd
35
2+
43
10 +
19
2-
27
10 -
36
3 Gnd
44
11 Gnd
20
3+
28
11 +
4
3-
12
11 -
5
4 Gnd
13
12 Gnd
37
4+
45
12 +
21
4-
29
12 -
38
5 Gnd
46
13 Gnd
22
5+
30
13 +
6
5-
14
13 -
7
6 Gnd
15
14 Gnd
39
6+
47
14 +
23
6-
31
14 -
40
7 Gnd
48
15 Gnd
24
7+
32
15 +
8
7-
16
15 -
9
8 Gnd
17
16 Gnd
41
8+
49
16 +
25
8-
33
16 -
33
Freeway input cards
Pro-Bel Ltd
5.5 4942 AES reference generator card
5.5.1
Theory of operation
Both the AES and analogue audio router require a source of digital audio reference to
function correctly. Without this reference, the clock circuitry on the 4945 and 4745
cards will free-run resulting in pathological operation.
The 4942 card receives and locks to the incoming studio AES reference when present.
If no AES reference is provided, the card generates it’s own internal reference using a
precision oscillator. In either case, the resultant reference is used to control the
reframing circuits on the 4945 card and to drive the ADCs on the 4745 card.
When the 4942 card operates in the external-reference locked mode, it generates a
reference signal which is used throughout the frame (signal = TAES) which is phaseadvanced in relation to the incoming AES reference signal. Any delay through the
router is compensated for, ensuring that the signals leaving the switcher conform to
the requirements of the AES 11-1997 standard (Synchronisation of digital audio
equipment in studio operations).
5.5.2
Installation and configuration
For diagnostic purposes, the 4942 card carries a dual-coloured LED which remains lit
green while a reference is present and goes red, if the reference signal is not present.
This LED is brightly illuminated in either condition and may therefore be seen when
the board is housed within the frame by looking between the cards from the front.
The 4942 card has no test points or user-serviceable adjustments.
Ref present
(dual coloured LED)
34
HU-Freeway Input Modules
Pro-Bel Ltd
Technical manual
5.6
4745 Analogue Audio module installation and
configuration
5.6.1 LED indications
In addition to the power and ‘HELLO’ LED’s on the card edge, 16 miniature LEDs
appear in the front right hand corner of the 4745 card. These LEDs are intended to be
used for input-status monitoring and may be used to determine whether audio signal
(or audio modulation) is present on each of the 16 inputs to the card. When an input’s
dynamic gate is set permanently OFF, these LEDs flag the presence of audio data,
irrespective of audio modulation and therefore remain permanently lit. When the
dynamic gate is set to ON, these LEDs indicate the presence of audio signal
modulation and remain off when digital silence is forced as a result of the operation
of the gate. In this mode the LEDs only illuminate when an audio signal is
dynamically UNGATED. The setting and operation of the gate circuitry modes is
covered in section 5.6.3.
For diagnostic purposes, the 4745 card carries a dual-coloured LED which remains lit
green when the internal reference signal (TAES) is present. If, for some reason the
internal TAES reference signal is not present, the LED flashes red. This indicates a
fault condition which must be rectified to ensure correct system operation. This LED,
although mounted towards the rear of the 4745 card, when illuminated in either
condition can be seen by looking between the cards from the front of the frame.
HU-Freeway Input Modules
35
Freeway input cards
Pro-Bel Ltd
5.6.2 ADC submodule
The 4741 sub-module comprises a stereo common-mode rejection amplifier driving a
20 bit stereo ADC and side-chain circuitry. Signals arriving at the 4741 module (over
and above the audio signals) include bit-rate and word-rate clocks, feeds and reset
pulses. The two important signals leaving the sub-module include the digitally
encoded PCM audio data and the side-chain gate-drive.
5.6.3 Setting Gate and Mute jumpers
Freeway incorporates a digital amplitude-driven signal gate for each analogue input.
This circuit is arranged so that signals below a threshold of approximately -75dBFS
(coded PCM) are forced to digital silence. Hysteresis and a time-constant of 2 seconds
ensure the gate does not ‘chatter’ on signals which dwell at low amplitude. With the
gate ON, signal to noise ratio is increased to over 100dB. Gate operation is selected
according to the position of the links illustrated in the following figure.
OFF
ON
GATE
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HU-Freeway Input Modules
Pro-Bel Ltd
Technical manual
n 5.7 Rear panel connections for analogue audio
The analogue input card uses a standard 16x16 Freeway audio router rear panel.
While the connector panel is fitted with four connectors, two are for inputs and two
for outputs, it is necessary in this instance to use only the input connectors.
Refer to the following diagrams for pinout details
1
50
50
1
Inputs 9-16
Inputs 1-8
Pin
Function
Pin
Function
Pin
Function
Pin
Function
1
Chassis
50
Chassis
1
Chassis
50
Chassis
34
Gnd
42
Gnd
34
Gnd
42
Gnd
18
9L +
26
13L +
18
1L +
26
5L +
2
9L -
10
13L -
2
1L -
10
5L -
3
Gnd
11
Gnd
3
Gnd
11
Gnd
35
9R +
43
13R +
35
1R +
43
5R +
19
9R -
27
13R -
19
1R -
27
5R -
36
Gnd
44
Gnd
36
Gnd
44
Gnd
20
10L +
28
14L +
20
2L +
28
6L +
4
10L -
12
14L -
4
2L -
12
6L -
5
Gnd
13
Gnd
5
Gnd
13
Gnd
37
10R +
45
14R +
37
2R +
45
6R +
21
10R -
29
14R -
21
2R -
29
6R -
38
Gnd
46
Gnd
38
Gnd
46
Gnd
22
11L +
30
15L +
22
3L +
30
7L +
6
11L -
14
15L -
6
3L -
14
7L -
7
Gnd
15
Gnd
7
Gnd
15
Gnd
39
11R +
47
15R +
39
3R +
47
7R +
23
11R -
31
15R -
23
3R -
31
7R -
40
Gnd
48
Gnd
40
Gnd
48
Gnd
24
12L +
32
16L +
24
4L +
32
8L +
8
12L -
16
16L -
8
4L -
16
8L -
9
Gnd
17
Gnd
9
Gnd
17
Gnd
41
12R +
49
16R +
41
4R +
49
8R +
25
12R -
33
16R -
25
4R -
33
8R -
HU-Freeway Input Modules
37
Freeway input cards
Pro-Bel Ltd
n 5.8 Expanding audio systems
Base Freeway audio modules may be expanded, with the addition of audio input
modules up to the maximum allowable size for the router type being expanded, i.e.
32x16 for Freeway 32 and 128x16 for Freeway 128. It is necessary to fit the
expansion module in the slot adjacent to the base router card or other input card
before connecting the ribbon cables across the front of the modules. As both the
analogue and digital audio variants utilise a common internal, digital, signal bus it is
possible to expand an AES base router with analogue input modules, and conversely
AES expansion cards may be used with an analogue base router.
Freeway 32 expansion
For Freeway 32, there is only one configuration using the input cards permitting
expansion from 16x16 to 32x16. The following diagram shows the cable connections
required for this expansion. Care should be taken to ensure that the level and
destination assign switches are set correctly, see sections 2.2 and 2.3.
Freeway 128 expansion
The following diagrams show the cable connections required for expanding base
routers from 16x16 for all possible combinations. Care should be taken to ensure
that the level and destination assign switches are set correctly, see sections 2.2 and
2.3.
38
HU-Freeway Input Modules
Pro-Bel Ltd
Technical manual
Freeway 128 can be expanded from 16x16 up to 128x128 in a single 6U frame,
however it is possible to expand from 16x16 to 64x64 in a single 3U frame using the
same Freeway 128 modules.
32x16 Expansion
HU-Freeway Input Modules
39
Freeway input cards
Pro-Bel Ltd
48x16 or 48x32 Expansion
64x16, 64x32 or 64x48 Expansion
40
HU-Freeway Input Modules
Pro-Bel Ltd
Technical manual
80x16, 80x32, 80x48 and 80x64 expansion
96x16, 96x32, 96x48, 96x64 and 96x80 Expansion
HU-Freeway Input Modules
41
Freeway input cards
Pro-Bel Ltd
112x16, 112x32, 112x48, 112x64, 112x80 and 112x96
Expansion
128x16, 128x32, 128x48, 128x64, 128x80, 128x96 and 128x112
Expansion
42
HU-Freeway Input Modules
Pro-Bel Ltd
Technical manual
n 5.9 Specification
n Digital input
Input impedance
110W balanced operation; 75W - unbalanced
Sample rate
22.05 to 96kHz (non re-clocking, non re-framing)
32 to 48kHz (re-clocking and re-framing)
Wordlength
16 to 24bit
Non re-clocking performance’
Transparent to all bi-phase mark data
Re-frame performance
TBC’s all inputs
n Analogue input
Input impedance
> 10k
Max level
+24dBu (not achievable into a 600W load)
Gain stability
+/- 0.1dB/24 hours
Frequency response
+/- 1dB 20Hz to 22kHz
THD + N
< 0.1% at 1kHz, +18dBu
< 0.1% at 1kHz, 0dBu
Dynamic range
>100dB: THD+N on -60dBFS tone referred to full
scale (AES17-1991)
Signal to noise ratio
>100dB (gate operative)
Gate closure level
»-55dBu (ie - 75dBFS), TC = 2 seconds, +2dB
hysteresis
Crosstalk
HU-Freeway Input Modules
<-90dB all hostile at 10kHz
43
Freeway input cards
44
Pro-Bel Ltd
HU-Freeway Input Modules
Pro-Bel Ltd
Technical manual
6 Problem solving
Card does not work at all
Things that may affect general system operation:
The green LEDs on the routing card are off
There is no power on the card.
·
check that there is power from the PSUs
·
check cable interconnections
·
ensure that the card is properly seated in the frame
The HELLO LED on the card remains off
No command has been received by the board.
·
check the power
·
check that the ‘level’ and ‘higher dest decode’ switches are set correctly
·
check cable interconnections
The ERROR LED is lit on the 2440 control card
There is a handshake error (faulty module)
·
check router has been re-configured correctly
Noisy or distorted signals present
Things that affect the signals.
Wrong output data mode configuration
· check that the destination on the AES card is configured correctly
Brief loss of power or reference
· try resetting the ADC and DAC chips on the analogue audio modules
Reference present LED flashing RED
· check audio level is fitted with a 4942 reference generator module
· check router has a valid AES reference
HU-Freeway Input Modules
45
Freeway input cards
46
Pro-Bel Ltd
HU-Freeway Input Modules
Pro-Bel Ltd
7
Technical manual
Optional hardware and spare parts
The following order codes relate to options and spare parts available for use with
Freeway 32 routing systems.
Extra PSU, 1941
FRE-N000-BPSU
Extra mP card, 2440
FRE-N000-RCPU
Spare parts
3U Freeway frame
FRE-3000-0FRM
6U Freeway frame
FRE-6000-0FRM
Serial digital video signal card, 3945
FRE-N000-DVIP
Serial digital video rear connector card, 1739
FRE- N000-DVRC
Analogue video signal card, 3745
FRE- N000-AVIP
Analogue video rear connector card, 1739
FRE- N000-AVRC
AES signal card, 4945
FRE- N000-DAIP
Balanced AES rear connector card, 1463
FRE- N00B-DARC
Unbalanced AES rear connector card, 1749
FRE- N00U-DARC
Stereo analogue audio signal card, 4745
FRE- N000-AAIP
Stereo analogue audio rear connector card, 1747
FRE- N000-AARC
HU-Freeway Input Modules
47