1.557 RX-Channel

The RX-Channel logical device controls the basic parameters of an IRD and an input switch for the IRD which selects antenna, frequency band and polarization. The device complements the TX-Channel logical device which provides a similar function for transmit chains.

RX-Channel supersedes a number of now outdated device like the RX-LineSettings-CDB device, which no longer should be used for new applications. The RX-Channel device supports a larger number of parameters, may be used in M&C and in NMS environments and it supports three alternative operation modes / work flows.

Heart of the RX-Channel device is a central database (CDB) storing the line settings for all satellite channels used in the system. In a NMS environment the database is located in the NMS server, providing an synchronization mechanism which creates local (read-only) copies of the database for offline operation of the VLCs. In a NMS environment, the sat-nms client software looks up the channel lists directly at the NMS database server which significantly reduces the amount of data which has to be exchanged between NMS and VLC. In a M&C environment the CDB is located at the M&C server, no synchronization is required in this case.

Although all individual IRD parameters are directly accessible with the RX-Channel device, the typical way to operate the device is to select a satellite channel from the list and to select the proper input signal for the IRD. The RX-Channel device assists the operator in this task with the following functions:

• The list of available input signals is dynamically generated by the device, the list entries are composed of "antenna name", "frequency band", "polarization" and satellite name. E.g. ANTENNA3-11Y-ASTRA19.2 denotes an 11GHz vertical signals, received from the ASTRA19.2 satellite through ANTENNA3. With motorized antennas, the satellite name is derived from the antenna's Antenna-Pointing device, telling the actually commanded satellite name.
• If you select a satellite channel from the database, parameters like frequency, symbol rate, DVB-S/DVB-S2 selection etc. are taken from the database and commanded to the IRD. Additionally the list of available inputs is confined to those signals which match the frequency band and polarization plane of the selected channel. You may remove this confinement at any time by selecting the "manual" satellite channel.
• The RX-Channel device accounts for the LO-frequency defined for a selected input and sets the proper receive frequency at the IRD (in terms of L-band frequency). If you change the input, the LO-frequency may change as well and the RX-Channel device commands a new frequency setting to the IRD.

Operation Modes / Work Flows

The RX-Channel device supports three different operation modes, thus is capable to be configured to meet the requirements of various work flows. The configuration parameter "workflowMode" selects the mode to be used.

FILTER-BY-CHANNEL The FILTER-BY-CHANNEL mode is the basic operation mode of the device. it resembles the behaviour of the former RX-ChannelSelect-CDB device. This mode assumes a work flow where the operator first selects a channel from the list of stored satellite channels, then selects the input signal for the IRD. The RX-Channel device assists the operator with a filter / autocompletion function in the channel field (typing a partial channel name reduces the list of displayed channel to those which contain the typed character sequence) and by reducing the list of selectable IRD input signals to those signals which currently match the satellite, frequency band and polarization plane of the selected channel.

FILTER-BY-SATELLITE The FILTER-BY-SATELLITE mode turns the work flow the other way round: The operator first selects the antenna to be used, then the satellite this antenna shall be pointed to. Selecting the satellite actually commands the antenna controller to point the antenna to this satellite. Next the device reduces the list of displayed satellite channels to those which may be received with this antenna/satellite. After selecting a channel from the list, the IRD parameters are set, the IRD input signal is selected automatically and - if necessary - the antenna is moved to point to the satellite referenced in the selected channel. Other functions of this mode are:

• A locking mechanism which protects an antenna from being turned away while receiving a certain signal. An operator may "lock" an IRD which prevents the operator from changing any IRD parameters in the RX-Channel device screen and from turning away the antenna from this or from any other RX-Channel or TX-Channel device.
• The locking mechanism used with this mode may be configured, that a lock only may be released from the same client PC which has set the lock.
• The device is aware of antennas with 2-port feed which may receive / transmit only at one polarization plane at a time. Locking an IRD receiving from such an antenna also locks the polarization plan selection for all devices to prevent the signal for the first IRD from being interrupted.

ACTIVATION-BASED The ACTIVATION-BASED operation mode is the most versatile of the three modes. It combines the 'first select the the satellite channel' paradigm of the FILTER-BY-CHANNEL mode with an advancement of the locking mechanism of the FILTER-BY-SATELLITE mode and adds a number of additional function to this. Here the most important one is, that the device is capable to select automatically an antenna which is suitable to receive the selected satellite channel. 'Activation' in this context means to select and point an antenna for the satellite channel to receive, to connect the IRD to this signal and finally lock the resources used to prevent other instances of the RX-Channel device from changing parameters which would interrupt the reception.

Device window pages

The following table shows which device window pages are available with this individual device type. Tool-bar functions not mentioned here are described at the general description of device windows .

• --- The main control (line settings select) page for the device. The layout of this page differs for the individual operating modes
• --- The line settings database editor page.
• --- The fault page
  • IRD Lock : The associated IRD is out of lock
  • Config File : The config file is not found, not readable or in a wrong format.
• --- The device info page.
• --- The maintenance page. The configuration parameters from this page are described below.

Operation (channel select)

The RX-Channel device supports three different operation modes / work flow settings which are selected by the 'operationMode' configuration parameter.

With 'operationMode=FILTER-BY-CHANNEL' (the default mode), selecting an already defined satellite channel is a simple 2-step procedure:

1. Select the desired satellite channel from the list.
2. Select the input signal.

Instead of selecting the satellite and channel you also may enter the receive parameters at the frequency / pol / symbol rate / fec fields. The RX-Channel device forwards these settings to the IRD. The input selection list gets confined to the inputs matching the frequency band of the entered frequency.

The FILTER-BY-CHANNEL mode also offers an option which automatically selects the input signal from the largest fixed pointing antenna which is capable to receive the channel after the channel has been selected. Manually selecting the input signal is not necessary in this case, but still possible, e.g. to override the automatic selection for using a turnable antenna.

With 'operationMode=FILTER-BY-SATELLITE', the 'channel' field only shows the channels of the satellite the selected antenna actually is pointed to. To move the antenna to another satellite, either the 'satellite' field in the TX-LineSettings-CDB's device screen may me used or the antenna may be controlled via it's own screen. Changing the antenna pointing automatically changes the subset of satellite channels displayed in the 'channels' field. The typical sequence of operation in this mode is as follows:

1. Select the antenna to receive from (field "antenna")
2. Select the satellite to receive with this antenna if this needs to be changed (field "satellite")
3. Select the satellite channel to receive. (field "channel", shows only channels from the selected satellite) Selecting the satellite channel will automatically select the appropriate l-band matrix input and set the IRD parameters. Only if the input selection is ambiguous, e.g. if the satellite can be received through a fixed and a motor driven antenna at the same time, the input selection must be done explicitly.

With 'operationMode=ACTIVATION-BASED' the typical work flow is as follows:

1. Select the desired satellite channel from the list.
2. Set the antenna select mode either to MANUAL, AUTO or AUTO-NO-FIXED. The latter mode skips (typically small) antennas with fixed pointing when selecting the antenna.
3. With manual antenna select mode select the antenna to be used
4. Click the "ACTIVATE" button.

With automatic antenna selection, the device searches for a suitable antenna and select this automatically. It selects the antenna with this priority (highest first):

1. A fixed pointing antenna receiving the selected satellite
2. A motor driven antenna which already is pointed to the selected satellite
3. A motor driven antenna which actually is pointed to another satellite but not in use. If more than one antenna is available in one of these search steps, the antenna with the larger diameter is used. The AUTO-NO-FIXED mode skips the first search step.

Operation (database edit)

With the second page of the device window of the RX-Channel device channel definitions are edited, copied or deleted. All RX-Channel devices in a sat-nms NMS share one common channel database located at the NMS server. The VLC containing the RX-Channel device requires an online connection to the NMS central database in order to make any changes to the database. Selecting channels at this page or changing any channel parameters do not change the receiver settings.

• Change certain parameters of a channel:
  1. Select the channel to modify
  2. Edit the settings
  3. Click 'SAVE'Please note that if you change the channel name (composed of the satellite / channel id entries), this will store a new channel definition with the modified data, the old channel is kept unchanged in the database.The channel name may consist of letters (a-z, A-Z), digits, space characters and some punctuation characters (,.-_). All other characters are turned to underscore characters when the channel gets stored.
• Save the actual receive settings as a new channel:
  1. Click 'READ' to fill the fields from actual receive settings.
  2. Optionally complete the transmit parameters for the channel.
  3. Enter the desired satellite / channel name.
  4. Click 'SAVE'
• Delete a channel:
  1. Select the channel to delete
  2. Click 'DELETE'

Local database copy

The following paragraph only applies to NMS installations. M&C installation manage their CDB locally at the M&C server and do not require a local copy of the data.

sat-nms VLCs may be operated locally by connecting an M&C client directly to the VLC. This may be used as a backup operation mode in cases where the NMS server is down or unreachable. To uphold the RX-Channel functionality even in this backup case, the VLC maintains a local copy of the channel database. This copy is used if the CDB at the NMS is unreachable. You cannot edit the channels in this local backup copy, but you can apply stored channels to the IRD.

There are two ways to update the local copy of the channel database at the VLC:

1. At the "Database" page of the device window of a RX-LineSettings-CDB device click "VLC UPD". This requests the complete database contents from the NMS server and stores it locally.
2. Administrators may configure a VLC to update the local database copy in regular intervals. To make a VLC update it's local database copy automatically, add a line cdb.channels.syncInterval=#.# to the file vlc.properties and restart the VLC. '#.#' is the time interval in hours.

EBU DREAMS channel list import

The channel database is capable to import channel lists from the EBU DREAMS software. The DREAMS channel lists are distributed as two CSV tables, on for RX and one for TX. In the sat-nms channel database these lists get merged. EBU channels are marked "read-only" in the database, they only may be changed by importing a new EBU channel list.

To import a pair of EBU channel lists, click the "IMPORT" button at the "Database" page of the RX-Channel device's device screen. This opens a new window where the names of the files to import must be entered. The small buttons beside the file name entry fields open a file select dialog which lets you select the file names fom the directory.

After you have set the file names, click "READ". The software reads and parses the CSV files. It also matches corresponding RX and TX channels, because the sat-nms channel database stores only one entry for each channel containing both, the RX and TX parameters.

The software reports the number channels read from each file and the number of channels matched. Sometimes the numbers slightly differ, e.g. if the original channel names in the RX and TX lists are not really identical. You have to edit and repair the original files if you want to fix this.

If you are satisfied with the parsing result, click "IMPORT". This imports the channel definitions to the sat-nms database. All existing EBU channel definitions are deleted and replaced by the new ones. The user defined channels in the database remain unchanged by this.

Please note, that this procedure copies the EBU channels directly from the client PC to the NMS server, the RX-Channel device is not involved in this and does not recognize the new channels immediately. This happens with the next regular update of the channel list, max 5 minutes later.

Configuration parameters

At the maintenance page of the device window there are a couple of configuration parameters which must be set to interconnect the RX-LineSettings-CDB device with the IRD and the input switch.

To make the RX-Channel device work, at least the frequencyId and symbolRateId fields must be set to the message IDs of the corresponding IRD parameters. If some other parameters are not supported by the IRD, leave the message ID fields empty, the same applies to the lock fault if a lock fault signalling in the RX-Channel device is not desired.

The configuration file format

The RX-Channel's configuration file is a plain text file which defines the matrix / switch input assignments. As this is a system wide assignment, you usually will edit one common configuration file for all RX-Channel devices connected to one input matrix.

In the file all empty lines and lines starting with a '#' character are ignored. All other lines are treated as table rows where the cells are separated by space characters. Each row describes one matrix input as follows:

Example:

#  Example configuration file for a RX-LineSettings-CDB device
#
#
#  input no.    polarization       freq. limit [MHz]
#  |            |                  |
#  |   antenna  |  LO freq. [MHz]  |
#  |   |        |  |               |

  01   ARD      X  9750.0        < 11800.0 
  02   ARD      Y  9750.0        < 11800.0
  03   ARD      X  10600.0       > 11800.0 
  04   ARD      Y  10600.0       > 11800.0 

  05   NDR      X  9750.0        < 11800.0 
  07   NDR      X  10600.0       > 11800.0 

  17   SNGR     X  9750.0        < 11800.0 
  18   SNGR     Y  9750.0        < 11800.0 
  19   SNGR     X  10600.0       > 11800.0 
  20   SNGR     Y  10600.0       > 11800.0 
   
  09   EBU      X  10000.0       < 11800.0   
  10   EBU      Y  10000.0       < 11800.0   

  11   W1       X  9750.0        < 11800.0 
  12   W1       Y  9750.0        < 11800.0 
  23   W1       X  10600.0       > 11800.0 
  24   W1       Y  10600.0       > 11800.0  

  13   ASTRA    X  9750.0        < 11800.0   
  14   ASTRA    Y  9750.0        < 11800.0   
  15   ASTRA    X  10600.0       > 11800.0   
  16   ASTRA    Y  10600.0       > 11800.0  
    
  21   EB_12V   Y  10600.0       > 11800.0   

  22   W1_V     Y  10000.0       < 11800.0   

  

The RX-LineSettings-CDB device parses this file on startup and when it receives a new name for the configuration file. So when you change the configuration file in the running M&C system, the best way is to restart the M&C server process to make all devices read the configuration file again.

Variables defined by this device driver