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Background

Variable Coding and Modulation (VCM) and Adaptive Coding and Modulation (ACM) are techniques that are strongly associated with the DVB-S2 standard. VCM can be used to provide different levels of error protection to different components within the service. It does this by allowing different combinations of modulation and FEC rate to be applied to different parts of the data stream. ACM extends VCM by providing a feedback path from the receiver to the transmitter to allow the level of error protection to be varied dynamically in accordance with varying propagation conditions. Claims of performance improvements exceeding 100% have been made for ACM in terms of satellite capacity gain. (continue reading…)

DVB-S to DVB-S2 Migration

DVB-S defines support for one modulation format (QPSK) and five FEC codes 1/2, 2/3, 3/4, 5/6 and 7/8, but DVB-S2 defines support for 28 combinations of modulation and codes (MODCODs) ranging from 1/4 QPSK to 9/10 32-APSK. (continue reading…)

Ubuntu Linux is a great basis for a general purpose MythTV Media Centre and has the latest version of MythTV (0.22) ready to install from its DVB software repositories. This guide shows you how to get MythTV working for free-to-air digital satellite channels in the UK with the new TBS 6925 card. However, much of it will be applicable to anyone using a DVB-S/s2 tv card. (continue reading…)

TBS 6925 is known as a professional PCI-E DVB-S2 TV Tuner Card, featuring VCM, CCM and ACM mode support and Multiple Transport Stream Receiving.

Here are the procedures of how to use the TSRecorder tool to receive DVB-S2 VCM, CCM and ACM signals. (continue reading…)