Broadcast Beat Magazine 2017 IBC Show - Page 83

as well as audio bars as shown in Figure 2. Tracking PTP Another challenge when it comes to IP networks is the fact that device clocks in IP video networks have no inherent con- cept of system time. To over- come this, precision time pro- tocol (PTP) is used to synchro- nize these clocks. In effect, PTP provides genlock functionality equivalent to that delivered by black burst or tri-level sync in SDI networks. The overall PTP network time server is referred to as a PTP grandmaster, with devices that derive their time from PTP being referred to as PTP Slaves. PTP grandmasters are usually synchronized to GPS, GLONASS or both. content, it is essential that the timing of the black burst/tri- level sync is not offset relative to the PTP clock. As shown in Figure 3, this is achieved by measuring the timing offset and then making any necessary correction by skewing the SDI syncs with reference to the PTP clock. To allow frame accurate switch- ing between SDI and IP derived Charlie Dunn is the General Manager for the Video Product Line at Tektronix focused on analysis and monitoring of con- tent in the rapidly changing landscape of media and enter- tainment. He brings more than 15 years of experience in the broadcast and professional video marketplace from his prior leadership roles in engineering, product management and marketing with Grass Valley, Inc. Charlie earned his Bachelor of Science Degree in Electrical Engineering from Washington State University and his MBA from University of California, Los Angeles Anderson School of Business. Broadcast Beat Magazine • www.broadcastbeat.com • 83