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Digital Radio –Digital Radio –Production & Transmission Production & Transmission
TechnologiesTechnologies
Presentation by: Yogendra PalYogendra PalDirector (Engg.)
All India Radio, New Delhi
AgendaAgenda
• Vinyl Disc to Optical & Magneto-optical Discs
• Tape to Hard Disc & Flash Memory
• Digital Audio Workstations
• Solid-state Recorders
• Digital Interfaces
• IP-based audio networks
• Issues for consideration
Vinyl Discs toVinyl Discs toOptical & Magneto-optical DiscsOptical & Magneto-optical Discs
MO DiscMO Disc
Tape to Hard Disc & Tape to Hard Disc & Flash MemoryFlash Memory
Solid-state Recorders
DAW
Digital Audio Workstation (DAW)Digital Audio Workstation (DAW)• Complete automation, scheduling,
production, play out, archiving etc.• Familiar transport control:
Play, stop, forward, rewind, pause• Keyboard short cuts• Touch screens• Nonlinear access• Waveform with zoom facility• Metadata• Large storage capacity
DAW – Controls & featuresDAW – Controls & features
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DAW -- MetadataDAW -- Metadata
DAW -- RecordingDAW -- Recording
• Two or more tracks
• Insert markers
• Play & edit while recording
• Recording by time & level
• Selectable:– Sampling frequency– Bit resolution– Compressed/uncompressed
DAW -- EditingDAW -- EditingNon-destructive with:• Cut/trim• Cut & paste• Copy & paste• Fade-in/out & cross-fade• Slip• Time indication• Time stretch, compress• Level changes• Colours for cuts
DAW -- SchedulingDAW -- Scheduling• Play list by drag & drop• Fade-in/out & cross-fade• Schedule part of
programme without copy• Block formation/insertion• Monitoring & editing
transition points• Copy of schedules• Last minute changes• Automatic schedule
preparation for criterion
DAW – PlaybackDAW – Playback• Manual, auto & live-
assist play• Two & more virtual
play panels• Monitoring start/end
points• Assignable hot keys• Fader start/stop• Auto play• Protection from
accidental exit
DAW – Effects & signal processingDAW – Effects & signal processing
Processing of:
• Spectrum
• Time
• Amplitude
• Noise
DAW – Other featuresDAW – Other features
• Traffic & Billing
• Report generation/printing
• Log printing
• Purging
• Logging
• Archiving
• Networking
Storage
Internet
Solid-state RecordersSolid-state Recorders
• No moving parts
• Flash memory card as recording media:– PCMCIA card– Compact Flash– SD card– Smart Media
• Cards capacity: up to 16 GB
• Uncompressed & compressed recording
• Easy transfer to DAW
Solid-state Portable RecordersSolid-state Portable Recorders
Sonifex (Courier)
Fostex (FR-2)
Marantz (PMD Series)
YouCom (Parrot)
Nagra (ARES-BB+)
Solid-state Handheld Solid-state Handheld RecordersRecorders
Edirol (R-09)
AEQ (PAW 120)
Nagra (ARES-M)
Samson (H-4)
HHB (DRM 85)
Land Lines
Typical Set up of a Radio Station
TransmitterRouter
From other Mixing Consoles
Mixing Console
Scenario & Options?
Audio NetworkingAudio Networking
ScenarioScenario
• Analog: Professional & consumer, with XLR, RCA, DB-9, DB-15, ¼” phone, mini phone and RJ-45 connectors
• Digital: AES3, TDIF, MADI etc.• Digital: Proprietary systems over fiber
& copper• Ethernet: Networking of DAWs
AES3AES3
• One-way communication
• Single source per cable limitation
• Control and data possible but for very simple, low rate functions
• Lack of flexibility
USB and FireWireUSB and FireWire
• Good for data transfer into and out of computer
• Can’t extend to multiple ports
Proprietary Audio networksProprietary Audio networks
• Used for connecting routers to each other and terminals
• Expensive
• Closed – all components from single vendor
• Connection to outside world still via analog, AES or MADI etc.
EthernetEthernet• Already in use: Computer network• Packet-switched network• Fast developments: 10 to 100 to 1000
Mbps speed & new protocol (IPv6)• Low cost – economies of scale• Standard, off-the-shelf products• RJ-45 plugs – fast & easy to install• Single network for audio, data,
telephony etc• Scalable
Ethernet – Issues & OptionsEthernet – Issues & Options
• Not designed for continuous stream of time critical data
• A number of proprietary systems now available which tackle the issue:– Livewire from Axia Audio (Telos)– Visiblu from Digigram– CobraNet from CobraNet Audio–Wheatstone from Wheatstone Corporation
LivewireLivewire
• Uses Internet IP standard
• RTP/IP for audio
• No sound cards
• Full-duplex links with priority assignment to audio streams
• Two types of streams:– Live streams – small, fast packets– Standard streams – bigger, non-critical data
Contd…
LivewireLivewire Contd..
• Single Ethernet cable carries:– Real-time uncompressed digital audio– Device control messages– Programme associated data– Routine network traffic– Clock signal for synchronization
• 50 audio channels (48 kHz, 20-bit)
• Ethernet switch isolates links and route audio
• Converged network
Livewire -- SchematicLivewire -- Schematic
VisibluVisiblu
CobraNetCobraNet
Wheatstone systemWheatstone system
Issues for considerationIssues for consideration
• Virus
• Backup
• Disaster management
• Sampling frequency and quantisation bits
• Compression
• Low cost systems
Compact Disc (CD)Compact Disc (CD)
• Developed as replacement of gramophone records
• Optical disc• Type Diameter Storage Audio capacity
Std 120 mm 650 & 700 MB 74 & 80 minutes
Mini 80 mm 184 MB 21 minutes
• Format: 2-channel, 16-bit PCM at 44.1 kHz• CD-ROM, CD-R & CD-RW came up later
Back
DVDDVD
• Diameter & thickness of CD
• High data capacity: up to 17.1 GB
• No. of Formats
• DVD-A:– Options for many channels at various
sampling frequencies and sample rates
– Distribution media for high-fidelity audio
– Robust copy protectionBack
Super Audio CD (SACD)Super Audio CD (SACD)
• Read-only, optical audio disc
• Looks exactly like CD
• Capacity: up to 7.95 GB
• Frequency response: DC to 100 kHz
• Dynamic range: 120 dB
• Audio format: Direct Stream Digital (DSD)
• Built-in copy protection features
• 3 types:– Hybrid, Single and Dual layer
Back
Mini DiscMini Disc
Yamaha MD8
Mindisc in cartridge (left), exposed minidisc (right) and protective cartridge holder (rear)
Back
Sony MZ-NHF800
• Removable, low cost & rewritable media
• Two types:
• Regular 74-minutes for 2-track
• Data disc for multitrack
• Records at 44.1 kHz, 16-bit. 24-bit also available
• ATRAC: Adaptive TRansform Acoustic Coding compression
MOMO DiscDisc
• 5.25” & 3.5” form factors• Casing• Information checking, reporting & correction
(Not available in CD-R & DVD-R)
• Dirt & scratch resistant:– Wide diameter of laser beam on disc surface but
narrow towards recording layer– Dropouts reproduced by error correction– No direct contact with disc surface
• High transfer speed – 5.92 MB/s• Capacity – up to 1.3GB (3.5”), 2.6GB (5.25”)
Back
AES/EBU (AES3)AES/EBU (AES3)
• Serial transmission of 2-channel digital audio• Balanced, 3-conductor, 110-ohm shielded twisted
pair cable with XLR connectors• Data rate depends on sampling rate
3.072 Mb/s at 48kHz
• Distance: up to 100 meters• Clock rate recovered by encoding data• For professional equipment• Can also be carried over an Asynchronous Transfer
Mode (ATM) network
AES/EBU (AES3)AES/EBU (AES3)
SPDIFSPDIF
• Digital Audio standard developed by Sony/Philips
• Consumer version of AES3• Unbalanced interface• 75-ohm coaxial with RCA
jacks or fiber cable with TOSLINK connectors
Back
USB (Universal Serial Bus)USB (Universal Serial Bus)
• Serial bus standard• Max. devices: 127 per host• Originally designed for computers• No termination needed• Hot plugging of devices• Latest version: USB 2.0• Transfer speeds: 1.5, 12 & 480
Mbps• Connectors: Series ‘A’, Series ‘B’,
Mini ‘A’, Mini ‘B’ & Mini ‘AB’Mini-A plug (left), Mini-B plug (right)
Series A Plug
FireWireFireWire
• Serial bus standard• Proprietary name of Apple Inc.• Max. devices: 63 in tree topology• Designed to replace parallel SCSI• Supports multiple hosts per bus• Supports plug-&-play and Hot
swapping• Transfer speeds: 100,200 & 400
Mbps for FireWire 400 and 800, 1600 & 3200 Mbps for FireWire 800
• Connectors: 4, 6 and 9 pins
9-pin connector
4-pin and 6-pin Plugs
Back
TDIFTDIF
• Tascam Digital Interface
• Proprietary format
• Bi-directional connection to transmit and/or receive up to 8-channels
• Separate cable for wordclock required in TDIF-1 but not in TDIF-2 protocol
• Uses 25-pin D-sub cable
MADIMADI(Multichannel Audio Digital Interface)
• Serial digital transmission over coaxial cable or fiber-optic line
• Supports 28, 56 or 64 channels, with sampling rates up to 96 kHz & resolution up to 24-bit per channel
• Bit-level description and features of AES3• Known as AES10
Back
