1. 1 HD Radio

2. 2 Content HD Radio Introduction FM HD Radio Basic Technical Description Methods of Broadcasting FM HD Radio AM HD Radio Basic Technical Description Methods of Broadcasting AM HD Radio IBOC System Networking Importer Plus Overview Exporter Plus Overview AM IBOC Exciter Overview Station Configuration for Multicasting Glossary of Terms and Acronyms

3. 3 HD Radio Introduction

4. 4 HD Radio IBOC (In-Band On-Carrier) allows AM and FM radio stations to simultaneously broadcast new digital services – audio channels and wireless data – and their traditional analog signal in their current spectrum. The analog and HD signals are separate signals at different power levels. These new digital signals are broadcast as "sideband" transmissions bracketing the top and bottom of the current "host" analog signal.

5. 5 RF Spectrum HD Radio transmission adds ~400 low power carriers to the RF spectrum –200 in upper sideband and 200 in lower sideband The HD Radio carriers range in frequency from 129,361 Hz to 198,402 Hz above and below the analog carrier –These carriers are modulated using QPSK and OFDM

6. 6 How HD Radio Works It works the same way that traditional analog transmits, except that the audio is digital formatted and transmitted as a continuous digital data stream in addition to the analog waveform signal. On the broadcast end, audio is digitally compressed and broadcast by a transmitter designed specifically for HD Radio broadcasting. The combined analog and digital signals are transmitted. Audio is transmitted in its analog form, as usual. The radio station sends out the analog and digital signals on the same broadcast frequency, along with the signals for the text data.

7. 7 How HD Radio Works On the listener end, the signals are received and decoded. An HD Radio tuner picks up the digital radio transmission with its accompanying text. Older analog receivers continue to pick up the analog broadcasters. Currently, stations broadcasting in HD Radio are operating in a hybrid mode of both analog and digital in order to reach both receivers.

8. 8 Power in the IBOC Carriers Each carrier power’s spectral density is -45.8 dBc or.0025% of analog carrier power The total HD Radio power is: –PTotal ~ 10LOG (400) + (-45.8 dBc) –PTotal ~ -20 dBc The average HD Radio power is ~20 dB below, or 1% of the analog carrier power New proposed injection levels at -10 dBc (10% of analog).

9. 9 Time Domain Unlike traditional FM transmission signals, the HD Radio RF envelop has amplitude variations over time The instantaneous voltage is the vector sum of the ~400 carriers When these carriers align, the vector sum results in a peak; when the vector sum nulls, a trough is created

10. 10 Time Domain Power measurement of this signal must quantify both the average power and the peak to average ratio (PAR) A good approximation for an HD Radio signal (carriers only) is the peaks have 4 times the power as the average, or PAR= 6 dB (actual PAR=5.5 dB) When a signal is composed of both FM and HD Radio carriers, PAR is reduced to approximately 1.5 dB due to the constant amplitude of the analog carrier dominating the signal content

11. 11 Fig: Time Domain of HD Radio RF Signal Time Domain

12. 12 RF Emissions Mask In order to minimize interference between adjacent stations, Ibiquity has proposed an RF emissions mask which details the permissible spectral output of the IBOC transmitter. To meet this mask, the transmitter must either have extreme linearity or filtering capable of removing the intermodulation products.

13. 13 FM HD Radio - Basic Technical Description

14. 14 FM HD Radio - Basic Technical Description FM HD Radio is an OFDM (Orthogonal Frequency Division Multiplex) system which creates a set of digital sidebands each side of the normal FM signal. The combined FM and HD Radio signal fits in the same spectral mask as is specified for conventional FM. The system allows for growth towards eventual full utilization of the spectrum by the digital signal. Hybrid Extended Hybrid Full Digital

15. 15 RF Spectrum of Hybrid Waveform Fig: Spectrum of hybrid waveforms Table: Hybrid Waveform Spectral Summary

16. 16 FM HD Radio - Hybrid Mode 109 kbps data throughput, 96 kbps for audio, and 1.411 kbps for PAD, balance is overhead. Multicasting up to three channels is possible Supports Stereo Analog and SCA / RDS Digital sub-carriers are 20 dB (1/100 th ) below analog The Upper and Lower Digital Sidebands are redundant Analog Host Signal (Stereo or Mono) 0 Hz Lower Digital Sideband Upper Digital Sideband 191 Subcarriers 10 partitions 191 Subcarriers 199kHz130kHz 199kHz Primary -20dBc

17. 17 FM HD Radio - Extended Hybrid Mode 151 kbps data throughput, assignable by the station There will be some impact to the host in extended hybrid mode Supports Stereo Analog and SCA / RDS Digital sub-carriers are 20 dB (1/100 th ) below analog Multicasting up to 3 channels is possible

18. 18 FM HD Radio - Full Digital Mode 300 kbps data throughput, assignable by the station Conventional FM signal is no longer present Multicasting up to 8 channels may be possible Not yet implemented in transmitter systems, or receivers.

19. 19 -200kHz 1 st Adj. +400kHz 2 nd Adj. +200kHz 1 st Adj. +400kHz 2 nd Adj. Noise Floor of Instrument -200kHz 1 st Adj. +400kHz 2 nd Adj. +200kHz 1 st Adj. +400kHz 2 nd Adj. Noise Floor of Instrument -200kHz 1 st Adj. +400kHz 2 nd Adj. +200kHz 1 st Adj. +400kHz 2 nd Adj. Noise Floor of Instrument -200kHz 1 st Adj. +400kHz 2 nd Adj. +200kHz 1 st Adj. +400kHz 2 nd Adj. -200kHz 1 st Adj. +400kHz 2 nd Adj. +200kHz 1 st Adj. +400kHz 2 nd Adj. FM Spectrum

20. 20 Separate Amplification Using a high power analog transmitter and separate digital transmitter Separate Antennas High Level Combining Common Amplification Using a hybrid FM + digital transmitter Low Level Combining Methods of Broadcasting FM HD Radio

21. 21 Separate Amplification Separate Antennas Spatial Combining – Similar to high level combining except each transmitter has its own antenna. The analog and digital antenna patterns must be similar in order to maintain the 20dB ratio in the broadcast area.

22. 22 Separate Antennas – New Architecture

23. 23 Separate Antennas Separate Antennas: Highest system efficiency Existing analog system unchanged At least 35 dB of isolation between antennas is recommended Many variations of antenna configurations Digital transmitter may be used as analog backup

24. 24 Separate Amplification High Level Combined High Level Combining – One transmitter amplifies the analog signal while another transmitter amplifies the IBOC signal. The transmitters are combined before the antenna. PAR for the IBOC transmitter is 5.5 dB.

25. 25 High Level Combined – New Architecture

26. 26 Requires 7 dB to 10 dB more digital power Requires at least 10% more analog power Overall system efficiency may be comparable to low level combined system Digital transmitter may be used as analog backup Separate Amplification High Level Combined:

27. 27 Common Amplification Low Level Combining – Both the analog and the IBOC carriers are amplified by a single transmitter. PAR is approximately 1.5dB.

28. 28 Low Level Combined – New Architecture

29. 29 AM HD Radio - Basic Technical Description

30. 30 AM HD Radio - Basic Technical Description AM HD Radio is also a OFDM system which creates several sets of sidebands each side and under the normal AM signal. The combined Mono AM, limited to 5 kHz, and HDRadio signal fits in a +/-15 kHz spectral mask and meets FCC requirements. The system can be converted to all digital at a future date for improved audio performance and increased ancillary data rate. Hybrid Mode Full Digital Mode Multicasting up to 2 channels may be possible.

31. 31 AM HD Radio - Hybrid Mode The AM HDRadio Hybrid mode supports the current AM Mono signal as well as the HD Radio signal 40 kbps data throughput, 36 kbps for Audio, 4 kbps for PAD Allocation adjustable C2 10kHz5kHz 0 Hz Lower Digital Sidebands C1 and C3 C2 C1 and C3 15kHz -28dBc -28dBc -40dBc-40dBc -50dBc Analog Host Signal (Mono) Lower Digital Sidebands Primary SecondaryTertiary SecondaryPrimary 5kHz10kHz 15kHz

32. 32 AM IBOC System AM IBOC (hybrid) has subcarriers out to +/-15kHz 81 OFDM subcarriers in each sideband (QAM @ 181.7Hz spacing) Subcarriers 54, 55, and 56 are not transmitted to avoid interference with a station 10kHz away. Subcarriers 27 and 53 carry IBOC Data Services (IDS). This information includes station information. Capacity is 400bps. Subcarriers are organized into primary, secondary and tertiary groups. Primary is 64QAM, secondary is 16-QAM and tertiary is QPSK. IDS subcarriers are 16 QAM.

33. 33 AM IBOC System Secondary and tertiary regions are under the analog signal. They are low power but they do pass through an AM detector. The upper and lower sideband secondary and tertiary subcarriers can be combined such that they are additive and the analog signal is subtractive. Receivers implement equalization to improve this process. Similarly TX equalization is helpful.

34. 34 AM IBOC Hybrid Signal Primary subcarrier levels are fixed. Secondary and tertiary are adjustable which is sometimes necessary to meet spectrum mask. IBOC data is ogranized into logical channels. Logical channels are signed to subcarrier groups based on service mode. MA1- P1 assigned to both primary groups (20.2kbps), P3 is assigned to secondary and tertiary groups (16.2kbps). MA2- P1 assigned to lower primary group (20.2kbps), P2 assigned to upper primary group (20.2kbps), P3 is assigned to secondary and tertiary groups (16.2kbps). NOT USED. Primary subcarriers (Fmax = +/- 14717Hz) Secondary subcarriers (Fmax = +/- 9629Hz) Tertiary subcarriers (Fmax = +/-4906Hz) analog

35. 35 AM HD Radio - Full Digital Mode Allows for a data rate of up to 60kbps. Full Digital Mode provides improved audio quality with song title/artist information. Two channel multicasting is possible with the full digital mode.

36. 36 -20kHz 2nd Adj +20kHz 2nd Adj AM Spectrum -20kHz 2nd Adj +20kHz 2nd Adj

37. 37 IBOC System Networking

38. 38 IBOC System Networking 38 NETWORK EQUIPMENT NETWORK EQUIPMENT SWITCH or HUB ROUTER 10.10.10.11 10.10.10.10 Gateway 10.10.10.12 External 24.24.24.24 OTHER NETWORK(S) Network Basics

39. 39 IBOC System Networking Network Basics  Network equipment is normally connected to a hub, switch or router.  A hub is the simplest LAN component. All traffic on any port is passed to all other ports.  A switch includes a high-speed processor and memory. It examines packet addresses and only forwards packets on the port that the addressed equipment is connected.  A router is used to separate networks. Separation protects networks and can be used to control traffic flow.

40. 40 IBOC System Networking Network Basics Applications exchange data as IP packets which can be TCP (destination acknowledges reception) or UDP (fire–and-forget). TCP is a reliable transport since the source will resend data if an acknowledgement is not received. Bidirectionality is a requirement. UDP is useful for broadcasting data to many destinations and can be used on a unidirectional channel, but the applications must be able to tolerate lost data. Ethernet is a physical layer that encapsulates IP packets into Ethernet packets. Ethernet protocol uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection). Delivery is not guaranteed.

41. 41 IBOC System Networking Network Basics –Network extended to a remote facility such as a transmitter site. Option 1: PC SWITCH ROUTER INTERNET ROUTER SWITCH PC LOCAL OFFICE REMOTE OFFICE  Requires connection to ISP at remote site

42. 42 IBOC System Networking Network Basics SWITCH PC ROUTER INTERNET BRIDGE SWITCH PC  More control over reliability, security and latency LOCAL OFFICEREMOTE OFFICE Option 2

43. 43 IBOC System Networking Network Basics –What can go wrong?  LAN throughput efficiency decreases as the number of devices increases. If the LAN becomes too slow, Ethernet devices may not be able to deliver packets. If the higher level protocol is TCP/IP, the packets can be resent. If the higher level protocol is UDP, the packets cannot be recovered.  If the data being carried contains audio, lost packets means lost audio. Even delayed packets are treated as lost if the audio they are carrying is late reaching the destination.

44. 44 IBOC System Networking SWITCH PC ROUTER T1 MODEM T1 MODEM T1 1.5 Mbs PC 100 Mbs Network Basics A LAN can contain cascaded switches and/or bridges. If any segment of the path between two device groups cannot support the throughput, packets will be lost due to buffer overflow in the switches and/or bridges.

45. 45 IBOC System Networking 45 Real Systems - Typical G3 Installation (audio paths not shown) IMPORTER EXPORTER SPS1 SAE SPS2 SAE STL Other Studio Devices STL E1, T1 Licensed RF Unlicensed RF Satellite TCP or UDP E2X LAN Switch TRANSMITTER with M50 GPS MPS SAE

46. 46 IBOC System Networking 46 STUDIO LAN STL IMPORTER GPS EXPORTER AUTOMATION SYSTEMS LAN AUDIO STL TRANSMITTER SITE (Low Level Combine) LAN STL M50 EXCITER TRANSMITTER AUDIO STL System Architecture - Importer/Exporter (G3 IBOC Exciter)

47. 47 IBOC System Networking Real Systems - I2E: Importer to Exporter  Must be bidirectional STL  Exporter requests channel data from Importer  TCP or bidirectional UDP  Latency from request to reply must be less than 140 ms

48. 48 IBOC System Networking Real Systems - E2X: Exporter to Exgine  TCP or UDP  Unidirectional or bidirectional STL  Includes CLOCK packets that can be used as a timing reference for the exciter’s master clock.

49. 49 IBOC System Networking 49 Managing the Traffic –The IBOC system is sensitive to lost data between the Importer, Exporter and Exgine.  Importer to Exporter: - Audio drop-out on SPS -Lockup of Importer software (rare)  Exporter to Exgine: -Receiver loses lock, taking several seconds to recover. -Exporter E2X interface can lock up requiring reboot (TCP only).

50. 50 IBOC System Networking Managing the Traffic - General Recommendations  I2E and E2X paths must be virtually error free -Bidirectional with resend -Unidirectional with very, very low BER (high SNR, FEC, etc)  Prevent unnecessary traffic from passing through the STL -Router to create a subnet. (some packet types go to all equipment on a subnet)  Maintain adequate bandwidth capacity in the LAN STL. ­Understand the utilization by each application using the LAN STL. ­Rule-of-thumb for good ethernet performance is 35% utilization.

51. 51 Importer Plus Overview

52. 52 Product Overview – Importer Plus The Importer Plus is used in digital radio transmission systems with Nautel's NE IBOC (In-Band-On-Channel) signal generator, Exporter or Exporter Plus. The Importer Plus allows multiple broadcasts within a single FM channel. It consists of a PC with compatible audio cards to support the secondary program. The Importer Plus' application software enables partitioning of the available transmitted HD (high definition) data bandwidth, between main program service (MPS) audio and other audio and data services, collectively called advanced application services (AAS). Audio AAS are called secondary program services (SPS), and include and program associated data (PAD).

53. 53 Importer Plus Broadcaster can implement two more digital program channels. The Importer contains the hardware and software necessary to supply Multicast and Advanced Application Services (AAS) Inputs for Multicast include secondary channel audio (AES/EBU) and associated Programmed Audio Data (PAD) Connects to IBOC Exciter via Ethernet using standard protocol (Exporter Link) Plug-and-play compatible with Nautel HD system Can be placed at studio (requires bi-directional link to site) or transmitter site (second AES/EBU STL channel required)

54. 54 AAS Overview This figure shows a block diagram of the AAS framework as part of the broadcast infrastructure. The 3 main elements are: 1) the clients (e.g. service providers and administrators) 2) the Importer 3) the Exporter.

55. 55 Importer Plus Inputs for Multicast include secondary channel audio (AES/EBU) and associated Programmed Audio Data (PAD) Connects to NE IBOC via Ethernet using standard protocol (Exporter Link) Plug-and-play compatible with Nautel HD system Can be placed at studio (requires bi-directional link to site) or transmitter site (second AES/EBU STL channel required) Units shipped support two secondary audio channels.

56. 56 Typical System

57. 57 Typical System

58. 58 Exporter Plus Overview

59. 59 Exporter Plus Quick Specs The Exporter Plus encodes main program service audio and combines it with audio and data services from the Importer. Dual ethernet interfaces support IP routing, which can be used to enhance the robustness of streaming HD IP data. The Exporter Plus is fully compatible with Nautel’s award-winning Reliable HD Transport protocol.

60. 60 Exporter Plus Overview The Exporter Plus represents the latest in HD Radio Exporter technology. Operates under the Linux Operating System. Accepts AES/EBU-format audio from an audio processor. In FM systems the Exporter Plus will also accept program service data (PSD) for the main program service (MPS) audio and Advanced Application Service data from an Importer via the Ethernet port. The MPS audio is coded and merged with PSD and Importer data to create a single data stream that is delivered to the FM exciter, also over the Ethernet port.

61. 61 Exporter Plus Product Overview The Exporter Plus may also be used to provide a delayed copy of the MPS audio for the FM exciter. The delayed MPS audio will become the analog component of the hybrid broadcast. The delay is necessary for smooth blending between the digital MPS audio and analog MPS audio in areas of poor reception. The Exporter Plus produces two MPS audio feeds, one of which is simply delayed, and the other which is coded for eventual transmission on the IBOC carriers. In FM systems the delayed MPS audio output is 44.1 kHz AES/EBU. In an AM system, the delayed MPS audio is part of the IP data stream.

62. 62 AM IBOC Exciter

63. 63 AM IBOC Exciter The AM IBOC Exciter is a companion device for the Exporter Plus when installed in Nautel AM broadcast transmitters.

64. 64 AM IBOC Exciter Overview The AM IBOC Exciter’s primary functions are: Modulating IBOC data received over an Ethernet connection from the Exporter Plus. Generating Magnitude and Phase outputs on two sets of RJ45 connectors, one set for a daytime transmitter and one for a night- time transmitter. Producing an RF output for a linear transmitter (when properly configured).

65. 65 AM IBOC Exciter Overview Typical Configuration Note: The Exporter Plus and AM IBOC Exciter should be located at the same site.

66. 66 Station Configuration for Multicasting © Nautel Limited 2009 This presentation has been produced for Nautel customers and agents and is not for distribution without the expressed written consent of Nautel.

67. 67 Topics –Importer to Exporter (I2E) –Exporter to Exgine (E2X) –Managing the HD Network –Provisioning the STL/LAN Link –Reference Timing

68. 68 Configurations There are two distinct physical configurations that the station may implement for deployment of AAS for multicasting on the HD Radio system: Importer to exciter (I2E) Exporter to exgine (E2X)

69. 69 Importer to Exciter (I2E) Configuration The I2E configuration connects an importer to an exporter/exgine via a bidirectional Ethernet connection. Only the Advanced Applications Services (AAS), such as multicast programming and data services, are transported by this link, which is not concerned with the main program digital service. A bidirectional link is required to accommodate the command and response nature of the I2E configuration.

70. 70 I2E Configuration Studio importer connection over bi-directional (duplex) STL. In this configuration, even with moderately bad network conditions (up to one percent packet loss and 100 millisecond latency) the system continues to perform well. The key is to provide adequate bandwidth overhead to allow the system to recover lost packets through TCP packet retransmission.

71. 71 I2E Configuration For a station running MP1 mode with 48kb/s of AAS, the average utilized bandwidth will be 54kb/s, requiring at least 90kb/s to be available through the STL. A 128kb/s LAN/WAN extender or two DS0s should provide sufficient bandwidth for any MP1 configuration. For the maximum MP3 extended hybrid configuration of one SPS at 48kb/s and a second SPS at 24kb/s, the minimum bandwidth required of the STL/WAN link is 156kb/s, requiring three DS0s for 196kb/s.

72. 72 Exporter to exgine (E2X) Configuration The importer-to-exporter-to-exgine (E2X) configuration is the most bandwidth-efficient method of deploying an HD Radio multicasting data network. With this implementation, a single data stream may be conveyed to the transmitter site over the STL/WAN link, which contains all of the MPS information as well as the Advanced Applications Services from the importer, such as SPS and associated data.

73. 73 E2X Configuration Importer to exporter to exgine configuration. Studio-to-transmitter transport of the E2X data stream is currently supported only as simplex (one-way) UDP and can operate over most unidirectional STL systems of sufficient bandwidth and robustness. With UDP transmission, the loss of a single packet results in the loss of the entire audio frame of which it is a part. The resulting outage will last for the duration of that single audio frame: 1.48 seconds.

74. 74 E2X Configuration A 128kb/s LAN/WAN extender or two DS0s will provide sufficient bandwidth for any MP1 configuration. For MP3, 256kb/s or four DS0s should be considered.

75. 75 Managing the HD Network Recommended network deployment of subnetting using VLANs. Because the STL system is usually the tightest bandwidth bottleneck in the HD Radio network, it is important that broadcast, multicast and other extraneous traffic be kept off the network path to the transmitter site. All HD Radio devices — importer, exporter and exciter — should use statically assigned IP addresses within their own subnet.

76. 76 Managing the HD Network The subnet must be separate from the rest of the facility through the use of VLANs or physically separated networks. The only way to be sure that no extraneous traffic is traversing the STL link is to place the entire HD Radio system on its own IP subnet as shown in the previous slide. The exciter should always be on the WAN subnet, which it may share with the exporter and importer, or the importer may be placed on program automation subnet. Except for equipment that may be necessary to build the infrastructure — that is, routers and switches — no other station equipment should be on the WAN link subnet.

77. 77 Provisioning the STL/WAN Link For TCP, the STL/WAN link must have a minimum of 40 percent reserve bandwidth to accommodate the temporarily higher data rates that occur when the stream recovers from packet loss. If a TCP WAN link is provisioned such that the aggregate data stream, including VNC, utilities and other extraneous traffic, occupies no more than 60 percent of the WAN link's available bandwidth, the installation should be successful under most network conditions. For UDP, the total traffic across the link should be no more than 75 percent of the provisioned bandwidth to allow for network contention.

78. 78 Reference Timing Synchronization Reference timing between the importer, exporter and exgine are not maintained across the network infrastructure. The use of GPS as a timing reference for the importer, exporter and exgine to precisely lock their respective clocks in step eliminates the phase and frequency issues and is highly recommended.

79. 79 Glossary of Terms and Acronyms

80. 80 IBOC System Networking Glossary of Terms and Acronyms BERBit Error Ratio. The ratio between the number of incorrect bits transmitted to the total number of bits. ExgineAn IBOC component which resides in the exciter. The Exgine decodes the exciter link data and provides the appropriate I/Q modulation. E2XExporter to Exgine FECForward Error Correction. A system of error control for data transmission. GUIGraphical user Interface IBOCNautel In-Band-On-Channel technology provides high quality digital audio over existing AM and FM radio channels.

81. 81 IBOC System Networking Glossary of Terms and Acronyms IPInternet Protocol. Specifies format of packets (or datagrams). Maximum packet size is 64 K, but typically set according to limitations of physical layer (1500 for Ethernet). I2EImporter to Exporter LANLocal Area Network MPSMain program Service OFDM Orthogonal Frequency Division Multiplexing: an FDM modulation technique for transmitting large amounts of digital data over a radio wave. QPSK Quadrature Phase-shift Keying: Phase-shift keying in which four different phase angles are used.

82. 82 IBOC System Networking Glossary of Terms and Acronyms SPS Secondary Program Service STL Studio-Transmitter Link TCP Transfer Control Protocol. Allows two hosts to establish a connection to exchange data and guarantees data delivery. TCP/IPGuaranteed delivery; requires two-way communication for packet acknowledgement. UDPUser Datagram Protocol. This is a connection-less protocol. There are few error recovery services. Typically used for broadcasting. UDP/IPDelivery is “fire-and-forget”. Can transmit to multiple destinations. Can be used on a one-way link.