1. Nautel HD Radio Configuration for AM/FM Systems Philipp Schmid
April 17, 2013

2. HD Radio Today Currently On air (Feb 28, 2013)AM
FM HD HD HD HD
Total Multicast: 1446
Total AM/FM stations currently on the air: 2040 (AM + FM-HD1)
Total HD Channels: 3486 (AM + HD1 + HD2 = HD3 + HD4)
HD Radio will be standard feature in most cars by 2015

3. HD Radio Services Multiple audio streams – multicasting
PSD – Program Service Data
iTunes tagging
Traffic services
Weather/Doppler maps
Artist Experience: Album Art
Nautel Demoed at NAB2012

4. data carriers QPSK ref carriers BPSK
FM Modes MP1, MP2, MP3
data carriers QPSK
ref carriers BPSK

5. FM IBOC Bit Rates MP1 MP3 Logical Channel Bit Rate Robust-ness P1
98.4kbps 2
PIDS
0.9kbps 3
Logical
Channel
Bit
Rate
Robust-ness P1
98.4kbps 2 P3
24.8kbps 4
PIDS
0.9kbps 3
MP1 is default without importer
1 audio, no data services
PIDS: Carries station information (SIS)
Call sign, slogan, emergency alert
logic channels can be divided across HD-1,2,3,4
Stereo (32kbps+), mono(16 kbps), parametric stereo (24kbps)
MP3 can allow for up to 4 audio streams
P1: HD-1,2,3 P3: HD-4
P3 conflicts with 92kHz SCA
P3 is low robustness, can drop out

6. AM Mode MA1 (30 KHz BW) 5 kHz AM audio BW secondary, tertiary carriers add audio quality 20.2 kbps kbps

7. AM Mode reduced BW MA1 only primary carriers 8 kHz AM audio BW parametric stereo HD-1

8. AM Mode all digital MA3 20 kHz BW 20.2kbps+ 20.2kbps

9. AM Mode all digital MA3 single channel mode 10 kHz BW

10. Nautel HD Radio Exciters
AM/FM NeIBOC OBSOLETE
FM VS Series VSHD adapter
DAC AD9779
FM M50 for V Transmitters/Other
AM NX Series integrated exciter
FM NV Series integrated exciter with HD PowerBoost
AM IBOC Exciter for XR/Jazz

11. Nautel HD Radio Exgine Exgine within NV exciter Ethernet E2X in
IBOC signal
out

12. Nautel ExporterPlus
Captures/Encodes HD-1 audio, sent to exgine over IP
Delays the analog FM audio to match
System time keeper via GPS
Receives importer data
Receives program service data

13. Nautel ImporterPlus
Captures/Encodes HD-2/3/4 audio, sent to exporter over IP
Interfaces to data applications
Bandwidth allocation manager

14. 3rd Generation IBOC Architecture
HD-2,3,4
lan stl
audio stl
unidirectional
bidirectional
exporter
synchronize
main
program
diversity delay
gps
codec
studio
automation
importer
digital exciter
ethernet
exgine
iboc modulation
fm processing
digital upconversion
transmitter
remote control RF
path
HD proc
audio proc
E2X Protocol
FM / HD-1
Architecture requires 2 types of studio transmitter links (STL):
Analog FM Broadcast Audio link
normally 44.1kHz digital AES, may be dropped to 32kHz AES
Digital general purpose LAN STL for E2X protocol
carries multiplexed exciter data packets requires reliable data delivery
carries clock packets for synchronization requires predictable latency
we see an increasing use of Ethernet based STLs to carry audio traffic
conceptually they are two STL paths
most equipment moved back to studio – cleans up transmitter site
after modulation we have a time varying signal that could be sample rate converted again. But this does not solve the problem of buffer management.
diversity delay at the studio adds robustness to the audio content across the STL
Challenge
exporter not considered studio equipment due to challenges of reliably carrying the HD traffic across the STL
cannot be rate converted at exciter <> needs locked processing rates 14

15. Thank You