The MO-180 is an SFN/MFN DVB-T/H modulator fully compliant with the DVB-T/H specifications ETSI EN300 744 v1.5.1 (including annex F referring to DVB-H), ETSI TS 101191 v1.4.1 (SFN synchronization) and ETSI EN 300 468 v1.6.1(DVB-SI). The unit is contained in a standard 19" 1U chassis.
The modulator has two DVB-ASI Transport Stream (TS) inputs and one DVB-SPI TS input. It also has a 1 pps and a 10 MHz input which, together with the MIP packet embedded in the transport stream, are used for SFN synchronization purposes. A loop-through 10 MHz output is available as well.
In MFNs we can operate the modulator in master and slave modes. In slave mode the modulator is locked to the incoming TS data rate, which is defined in document ETSI EN 300744 for each choice of DVB-T/H transmission parameters. In master mode the modulator is locked to either the internal 10 MHz TCXO or to an external 10 MHz reference. The input bit rate has to be strictly smaller than the value given in the DVB-T/H specification. The MO-180 drops or inserts NULL TS packets as required to adapt the bit rate to the required value.
PCR re-stamping is implemented to minimize the impact of the bit rate adaptation process on the timing jitter of the MPEG-2 TS multiplex.
In SFN mode, the modulator can be synchronized with the external 10 MHz GPS reference or with the incoming TS data rate. A loss of sync with the external 10 MHz reference can be used to make the modulator lock to the input TS rate, and vice versa. This means that disruptions to the output IF/RF COFDM signals are minimized. Periodic or a periodic MIP packets are constantly monitored so as to dynamically adjust the delay of the modulator. In non-hierarchical transmissions the modulator seamlessly switches between ASI inputs when it detects a sync loss on the currently selected TS input. An additional test TS can be generated internally. This allows to generate compliant. DVB-T/H signals even in the absence of a valid TS input.
The channel bandwidth can be set to 5, 6, 7 and 8 MHz with no variation in performance. The DVB-T/H signal is output in both IF (36 MHz, 0 dBm) and RF (45 MHz to 875 MHz, at-27 dBm with the option of going up to 6 dBm) with a resolution of 1 Hz. The polarity of the spectrum may beset to normal or inverted.
The MO-180 supports 2k, 4k and 8k modes and non-hierarchical and hierarchical transmissions. Several test modes are available (blanking of carriers, single tone output, test TS generation, CBER and VBER injection). The MER typically measured in IF is above 41 dB. In RF we measure MERs greater than 35 dB.