A BETTER LISTENER EXPERIENCE: HD RADIO TIME AND LEVEL ALIGNMENT

Transcription

1 A BETTER LISTENER EXPERIENCE: HD RADIO TIME AND LEVEL ALIGNMENT NAB Broadcast Engineering Conference - April 17,

2 HD RADIO TECHNOLOGY AND YOUR AUDIENCE More of your listeners are experiencing your station in digital every day More than 29 million HD Radio Technology receivers are in the marketplace In several US markets 1 car in 5 already has HD Radio Technology Over 95% of all Americans live within the coverage area of an HD Radio signal 2

3 YOUR LISTENERS ARE PAYING ATTENTION Compelling Multicast Content is Attracting New Listeners Listeners Appreciate the Quality Improvement Displays and Interface are Attracting New Car Buyers Artist Experience is Leveling the Playing Field with Other Media However... Time and Level Alignment Set Incorrectly Leads to: Blend Echoes, Repeats and Level Changes Listener Dissatisfaction Leads to: Automotive Customer Service Complaints Listener Tune-Over to Your Competition Listener Tune-Out to Other Media 3

4 MARKET IMPACT NEW YORK Market Snap-Shot 2.3 Million HD Radio equipped cars in market 6.8 million hours of weekly in-car listening HD Radio broadcasts 26% of stations out of alignment could impact 1.8 million hours of listening and 600,000 listeners 4

5 DIVERSITY DELAY DTS HD Radio Technology is significantly more robust than analog. Digital not immune to signal disruptions Signal obstructions Loss of digital at the edge of coverage Time diverse transmission can help Transmission of backup time diverse program and data channel Used during signal outage Requires perfect synchronization? in the receiver for a good Direct user experience Reflected Obstructed 5

6 BLEND TRANSITION FUNCTION (CROSS-FADE) Transition Time Composite Audio Output Transition Function Analog Audio Digital Audio Time 6

7 TIME-DIVERSE BLEND Signal Impaired Time Analog Delay Digital Transmitted Analog Digital Delay Received 7

8 DIVERSITY DELAY OPTIONS Diversity Delay is added to the analog audio path Delay is typically controlled in one of the following locations: Audio Processor Exporter Stand-Alone Delay Unit 8

9 IBOC Audio Path PROCESSOR - DELAY FM Audio Path IBOC Audio Path Combined IBOC/FM Audio Processor Composite Composite UDP UDP Exgine Analog Exciter Exporter 9

10 IBOC Audio Path FM Audio Path EXPORTER - DELAY FM Audio Processor Composite Composite FM Audio Path Exporter UDP UDP Exgine Analog Exciter IBOC Audio Path IBOC Audio Processor 10

11 IBOC Audio Path FM Audio OUTBOARD - DELAY FM Audio Processor Composite Audio Delay Composite FM Audio Path Exporter UDP UDP Exgine Analog Exciter IBOC Audio Path IBOC Audio Processor 11

12 SYSTEM TOPOLOGY - ALIGNMENT PERFORMANCE Separate audio processing /Data circuit performance System synchronization 12

13 IBOC Audio Path SEPARATE PROCESSOR SEPARATE LINK FM Audio Path FM Audio Processor Composite Composite Exporter UDP UDP Exgine Analog Exciter IBOC Audio Path IBOC Audio Processor 13

14 IBOC Audio Path SEPARATE PROCESSOR - COMMON LINK FM Audio Path FM Audio Processor Composite UDP UDP Composite Exgine Analog Exciter Exporter IBOC Audio Path IBOC Audio Processor 14

15 MOVING PIECES Dissimilar Processing Lack of AES WordClock Ʈc 15

16 AES PHASE REVERSAL EFFECT ON BLEND A B In-Phase = Constructive Addition A = B Destructive Addition 180⁰ Out-of-Phase 16

17 SAMPLE OFFSET IMPACT TO AUDIO AT BLEND Aligned - 0 Samples 2 Sample Offset 1 Sample Offset 3 Sample Offset 17

18 SAMPLE OFFSET IMPACT TO AUDIO AT BLEND 4 Sample Offset 6 Sample Offset 5 Sample Offset 7 Sample Offset 18

19 SAMPLE OFFSET IMPACT TO AUDIO AT BLEND 10 Sample Offset 50 Sample Offset 20 Sample Offset 100 Sample Offset 19

20 PHASE ROTATORS EFFECT ON TIME CORRELATION Peak Limiter Normal Voice 6 db Normal Vocal Audio Phase Rotated Vocal Audio Phase Rotated Vocal Poor Correlation 20

21 SYSTEM TOPOLOGY - ALIGNMENT PERFORMANCE Separate audio processing /Data circuit performance System synchronization 21

22 / DATA CIRCUIT PERFORMANCE System Needs To Provide Coherent Analog And Digital Program Paths Variable Delay In Any Part Of System Will Translate Into Alignment Issue Protocols UDP Path Loss Translates Into Digital Signal Outage TCP/IP Protocol Resolves Intermittent Outages Cannot Correct More Packet Errors Than Are Held In Buffer Buffer Size Determines Recovery Period 22

23 SYSTEM TOPOLOGY - ALIGNMENT PERFORMANCE Separate audio processing /Data circuit performance System synchronization 23

24 SYNCHRONIZATION GPS (STUDIO & TX) STUDIO SITE 10 MHz Clock (GPS Derived) Exporter Importer /Channel E2X Modem Frame Boundary Clock Messages TRANSMITTER SITE Synchronized 10 MHz Clock (GPS Derived) Exgine Exciter HD Radio Broadcast Signal 24

25 SYNCHRONIZATION CONVEYED OVER LINK 10 MHz Clock (GPS Derived) Exporter Importer STUDIO SITE /Channel E2X Modem Frame Boundary Clock Messages TRANSMITTER SITE Synchronized Exgine Sync 10 MHz Remote Clock Synchronizer 10 MHz Clock (synchronized to Exporter 10 MHz Clock) Digital Up- Converter HD Radio Broadcast Signal 25

26 SYNCHRONIZATION - COLLOCATED STUDIO SITE Importer /Channel TRANSMITTER SITE Exporter Synchronized 10 MHz Clock (GPS Derived) Exgine Exciter HD Radio Broadcast Signal 26

27 NETWORK OVERVIEW HD Radio Monitoring and Reporting System DTS Centralized Data Analytics Platform 50 Markets Currently Monitored Real-time market observations Web-based interface Automated trouble ticketing and notifications* Historical and trend analysis Monitoring and reporting on: Time and level alignment Program information and HD2/HD3/HD4 audio services All advanced services - images, traffic, etc. Scheduled Q Top 50 markets + Calgary, Vancouver, and Mexico City 27 27

28 HD RADIO MONITORING NETWORK Real-Time Market Observations On-Line Scheduled 2016 Top 50 U.S.; 6 Canadian Markets; Mexico City 50 Markets currently monitored 685 Monitored Digital Stations 1,340 Monitored Digital Channels 20.9 Million HD Radio- Equipped Cars 58.0 million hours of weekly listening 70% of all in-car Digital Radio listening 28

29 MONITORING TIME ALIGNMENT STATION DETAIL 29

30 SNAPSHOT OF STATIONS OPERATING WITHIN PARAMETERS 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Less than 400 Samples Off Between 400 and 800 Samples Off Greater than 800 Samples Off 30

31 TIME ALIGNMENT WITHIN 3 SAMPLE SPEC. 31

32 TIME ALIGNMENT SAMPLES OFF & VARIABLE 32

33 TIME ALIGNMENT SAMPLES OFF & VARIABLE 33

34 AUTOMATED ALIGNMENT TOOLS AVAILABLE TODAY BELAR FMHD-1 Delay monitor Correlates received audio Offset correction to external audio buffer (exciter, audio processor) Time alignment to +/- 1 sample Alarms DAY SEQUERRA M4DDC In-chain audio alignment Correlates received audio Time alignment to +/- 1 sample Level alignment Phase alignment Alarm functions INOVONICS JUSTIN 808 In-chain audio alignment Correlates received audio Time alignment to +/- 1 sample Level alignment Phase alignment Alarm functions 34

35 CONCLUSIONS Use Common Dual Output Processor If Separate Processing: Match Analog and Digital As Closely As Possible Both AES Audio Paths Must Use Common Wordclock Collocate Exporter and Exgine When Possible If Not Collocated; GPS Lock both Exporter and Exgine Automate Time and Level Alignment 35

36 THANK YOU DTS Inc Las Virgenes Road Calabasas, CA USA 36