The rapid transition from analog-to-digital television has spread throughout the world over the last decade plus and is still on-going. Satellite and cable were the first to deliver digital video broadcasting (DVB) services followed by terrestrial (DVB-T) broadcast systems. Several of our major clients are equipment suppliers for DVB along with digital audio broadcast (DAB) systems.

DVB-T uses Single Frequency Networks (SFN) with advanced modulation techniques to optimize spectrum and bandwidth. SFN transmitters all operate on the same frequency, so they require precision synchronization to broadcast multiple channels in megaframes with minimum guard intervals. The use of the guard interval is required for SFN and provides for efficient utilization of the radio spectrum. This allows for a higher number of radio and TV programs in comparison to traditional transmission techniques. The signals from each transmitter in the SFN need to be accurately time-aligned, which is usually done with GPS timing at each transmission point. A GPS-based time and frequency standard, such as the Tycho II, provides 10 MHz and 1 PPS signals to enable this synchronous transmission from SFN transmitters with a high quality-of-service.

The use of GPS at each transmission point adds to the cost of deploying DVB-T or DAB networks. The Precision Time Protocol (PTP/IEEE-1588) is an IP network protocol that distributes a clock signal with the quality required for DVB-T or DAB.  This lowers synchronization cost by allowing for a minimum of GPS receivers in conjunction with PTP-based devices. In addition to sourcing 10 MHz and 1PPS signals, the Tycho II Time & Frequency Reference can also be used as a PTP Grandmaster.