MCT Multichannel Transmitters

The multichannel system provides up to eight physical slots.
Devices 1 to 7 are the main modulators, each of them is configured with different parameters in order to transmit either DVB-T or ITU PAL modulation, with different parameters and also different output channels.
Device 0 is the reserve, used for redundacy in case of failure of one of the main transmitters.

The role of each device inside the system is defined by its position in the chassis.
Each device has in memory a mapping of all the settings of each possible position. This way, any device can perform the same functionalities as any other in the same Multichannel system. This ensure better spare part management and logistics.

Each device uses a keyword (magic number) that enables the device to work in the system. On new blades, this keyword has a default invalid value that is set to valid only after a proper configuration of the device itslef is performed.

A new device inserted in the system must be configured before to activate, by performing the following operations:
• Download the system devices configuration. This operation polls the other system devices and transfer the configuration of all the system devices (including the configuration of the former device present in this slot) in the EEPROM memory.
• If a device was previously present and configured in this slot perform a Load command to run the correct configuration downloaded on EEPROM.
• If a new configuration is needed, configure the device settings (by manual configuration or by file loading via GUI)
• Save the configuration. By performing this command the configuration is saved inside the device EEPROM and transferred to the memory of all the others devices of the system.
• The last operation also write the correct magic number in memeory and activates the device.

Performing a memory reset command before moving a device to a different system is mandatory to avoid uncorrect and potentially destructive configurations.

N + 1 REDUNDANCY
The system is composed by N (up to 7) Multichannel elements and 1 reserve. Each device stores its own currently running set of parameters, used to define e.g. modulation mode, output channel, input satellite settings and modulation. It also stores all the other devices configurations.
One device is used as reserve: it stores all the other devices configurations in order to provide redundancy in case of failure of one of the main modulators.
The reserve device normally is in stand-by mode waiting to be enabled from a failure signal from one of the main modulators.

MANAGEMENT
The System makes use of a shared serial bus where every unit has its unique address. There is a central serial proxy which manages the communication with each board. All the board, in their default state, are in listening mode.
A dedicated command tells to all the boards which is the unit to which the central node needs to communicate.The selected unit performs the necessary configuration communications. When the communication ends all the boards enter again the "listening" mode.

ALARM MANAGEMENT
Hereafter follows a list of alarms:
• Satellite input not locked - The satellite input signal did not lock.
• Satellite input high BER - A BER higher than a programmed threshold was measured in the satellite input signal.
• Satellite input low S/N - A S/N lower than a programmed threshold was measured in the satellite input signal.
• No input TS - a valid TS was not found at the descrmabled input of the modulator.
• De-scrambling error - the receiver returned error while descrambling.
• Input service not found - the service selected is not valid or no more present in the input TS.
• Failed device enabling - the device has an incorrect keyword and needs to be re-configured before being enabled.
• 10 MHz clock alarm - the 10 MHz failed to lock to the external 10 MHz.
• 1 PPS alarm - 1 PPS external signal was missing.
• System delay alarm - the system cannot lock its internal reference timing to the STS received from MIP and cannot perform a correct SFN transmission.
• No MIP alarm - a valid MIP packet was not found in the input TS.

Graphic User Interface
A central management interface is dedicated to the configuration and monitoring of the System.
Enter the IP address of the System in order to connect it.
To configure the units:
• Select from the upper left button the unit to be configured (label A).
• Select the appropriate mode, PAL or DVB, for the unit (label B).
• In case of PAL mode, select with a double click the program to be converted from MPEG2 o PAL from the upper right section (label C)
• Note that the program is selected and correctly reported in lower left corner (label D)
• Save the settings (label E)

When saving, the configuraion of the board is sent to all the others.
Repeat the same for all the primary N boards.
Phase 1
> Seven transmitters are transmitting on the following channels using DVB-T modulation: A: CH 51, B: CH 48, C: CH 45, D: CH 42, E: CH 39, F: CH 36,G: CH 33
> The satellite input is set with the following parameters:
- Bouquet: Mediaset 2
- Satellite: HotBird 13° E
- Standard: DVB-S2
- Frequency: 11431 MHz
- Simbol Rate: 27500 kbaud
- Polarization: Vertical
- Input stream id: Not Set

Phase 2
The reserve device is in stand-by waiting for the failure of one of the main transmitters.
> Multichannel device C fails due to an hardware problem.
> A Fail alarm is raised on the backplane line on which the device is connected.

Phase 3
The reserve device load the parameters of the failed device and starts to transmit acting as the Multichannel C.