First DVB-C2 Plug-Fest

First DVB-C2 Plug-Fest at Kabel Deutschland RF Labs in Berlin

It became quite a busy day on Monday, 27th February 2012, when more than twenty DVB-C2 experts from all over Europe, as well as from Korea, came together on the invitation of DVB to the RF labs of Kabel Deutschland in Berlin, to test their prototype implementations of the new DVB-C2 standard for the first time. They were setting up their modulators and tuner/demodulators for testing in a realistic cable environment. The DVB-TM Ad-Hoc Group TM-C2 had prepared a detailed schedule and related technical testing configurations for the three days of the Plug Fest.

Detailed information on the Plug Fest had been distributed in advance. During the kick off meeting of the Plug-Fest all test configurations, parameter settings and measurement procedures were introduced and discussed. The second half of the first day was devoted to interoperability testing of the four different DVB-C2 modulator implementations with the three different DVB-C2 demodulator implementations. A total of 128 Test Cases had been defined by the TM-C2 Verification & Validation Group. All different configurations of the four DVB-C2 modulators were tested with the available eight tuner/demodulator (five tuner/demodulators used the same chip set) implementations.

The technical highlight of this first Plug Fest was for sure the new DVB-C2 demodulator implementation of LG Electronics. Three research engineers from the LG Electronics SIC Center in Seoul (Korea) tested their PFGA (Field Programmable Gate Array) design of a DVB-C2 demodulator for the first time with other DVB-C2 implementations. The LG experts were very proud that their chip was able to synchronize on most of the provided test signal configurations. Many data stream recordings were made by them in order to further evaluate their design in their lab environment.

The second and third day addressed the performance requirements of the DVB-C2 modulators and the tuner/demodulator devices in a realistic cable environment. Based on the theoretical minimum signal-to-noise ratio required for error free reception of DVB-C2 signals, the TM-C2 Group had developed a reference model distributing the typical distortions of an end-to-end DVB-C2 cable transmission system to the different components of the transmission chain. The calculated performance requirements were validated with the different modulator and tuner/demodulator implementations. 

From the afternoon of the second day the focus of all tests was on the performance of the tuner/demodulator implementations. The first set of receiver tests addressed the tuner noise performance. With different DVB-C2 signal configurations the minimum input signal level for error free video decoding was evaluated for the eight tuner/demodulators under test. During the following set of measurements the linearity of tuners was evaluated. Again the minimum input signal level for error free decoding was measured with signals transmitted in four different channels spread over the cable frequency bands. Almost one complete day of the tuner/demodulator measurements was devoted to adjacent channel measurements. Those tests addressed all realistic scenarios, where DBV-C2, or DVB-C or analogue PAL signals are transmitted in lower and upper adjacent channels to the DVB-C2 signal under test. The results of these measurements were used to determine  the protection ratios (ratio of interfering signals to signal under test) for error free decoding of a DVB-C2 signal.

The tuner/demodulator tests consisted of more than 1000 test configurations. In order to cover this within two days, a careful preparation of the different measurement configurations and stringent handling of the measurement procedures were essential. In the afternoon of Wednesday, 29th February more than 20 participants of the first DVB-C2 Plug Fest were pleased as they had successfully fulfilled the challenging schedule and completed all the planned tests. Each participant had noted his individual results and there will be a summary report distributed to all, outlining only the range of results measured with each of the tests. The combination of the individually noted results and the range of results in the summary report will give every participant an indication of the quality of his prototype implementation. Thus the confidentiality of the individual results is ensured and the participants have clear indications whether there is room for improvement for the different quality parameters of their implementations.

The participants and the TM-C2 team were satisfied after the three exciting and busy days in Berlin. A new milestone for the implementation of DVB-C2 has been reached. The participants have gathered important information for further optimization of their DVB-C2 implementations. They promised that their devices would work perfectly if DVB would like to invite them for a second Plug Fest in autumn 2012.