Accumulators, logic, 57 ADCs (analog-to-digital convertors), 129–34
droop problems, 133
noise-shaping ADCs, 148–51, 153–5
ramp integrators, 133
residual expansion, 134
serial quantizing, 132
Adders, half and full, 56
AES/EBU digital audio interface, 250–9
CRCC, 259
EBU timecode, 350
HDLC (High-level Data Link Control), 259
minimum eye pattern, 252
parity, 254
professional channel status structure, 255–9
synchronization approach, 263–5
synchronizing patterns, 254
user bits/channel, 259
Airy distribution/pattern/disk/function, 379–81
Analog audio:
Analog-to-digital convertors see
ADCs Anharmonic distortion, 115
Anti-aliasing filters, 97
Arbitration and priority:
Area divided track following (ATF), DAT, 309–11, 313–14
Asynchronous operation, networks, 265–6
ATM (asynchronous transfer mode), 276–81
cell-routing mechanism, 276
connection oriented protocols, 278
container structures, 276
program clock reference (PCR), 281
Reed-Solomon FEC, 280
UDT (unstructured data transfer), 279
virtual channels and links, 278
see also Broadband networks
ATSC (advanced television systems committee), 177
Audio technology:
Auditory masking, 160
BER (bit error rate), 223, 227
Binary systems/signals:
advantages, 5
most and least significant bits (MSB and LSB), 7–8
and noise, 6
representation methods, 7
two’s complement system, 49–52
see also Digital logic
Bit error rate (BER), 223, 227
Bootstrap programs, 58
Broadband networks:
B-ISDN (Broadband ISDN), 276
connectionless protocols, 278
SDH (synchronous digital hierarchy), 276–8
SONET (synchronous optical network), 276–8
see also ATM (asynchronous transfer mode)
Broadcasting, digital audio, 21–2
CAT (Conditional Access Table), 293
CDs (Compact Discs):
disk manufacture process, 383–5
error-correction strategy, 393–7, 400–1
Karaoke system, 402
MD comparisons, 364
phase-contrast microscopy, 361
sampling rate, 103
surface contamination rejection, 366–9
timing structure/relationships, 391–2
WORM (write-once-read-many) disks, 361, 362–3
see also Channels/channel coding; Optical/magneto-optical recording/ playback
Channels/channel coding:
coding concept, 18
data separators, 213
eight to fourteen modulation (EFM), 388, 390
encryption systems, 221
FM code/Manchester code/bi-phase mark code, 215–16
MFM (modified frequency modulation)/Miller code, 217–18
Non-Return to Zero Invert (NRZI), 215
see also Transmission channels
Characteristic impedance, 197
Clock references:
and numerically locked loops (NLL), 291
program clock reference (PCR), 291–2 and voltage-controlled crystal oscillators (VCXOs), 291–2
Codewords, 227
Coding/coders/codecs see Channels/channel coding; Compression/compressors; Error detection/correction
Communication networks, 22
Compression/compressors, 157–91
applications, 159
basic concepts, 11–13, 18–19, 157–9
cascaded systems, 168
codec level calibration, 164–5
companders (compressors/expanders), 157, 168–71
crash knee/cliff-edge effect, 166–7
delay effects, 167
discrete cosine transform (DCT), 172
discrete frequency transform (DFT), 83–5, 172
entropy, 161
Huffman code, 163
inter-block prediction, 176
inverse transforming, 176
Lempel-Ziv-Welch (LZW) lossless codes, 161
lossless (predictive) coding, 159–60, 164
lossy (perceptive) coding, 160, 161–2, 164
modified discrete cosine transform (MDCT), 172, 183–4
noise to masking ratio (NMR), 165–6
perceptive coding, 160
perceptual entropy, 166
Precision Adaptive Sub-band Coding (PASC), 321
principles of compression, 160–4
quadrature mirror filtering (QMF), 173–4
redundancy, 161
statistical multiplexing, 162
subjectively lossless systems, 162
variable length coding, 163
see also MPEG Layers I, II and III, and MPEG-2 AAC
ALUs (arithmetic logic units), 60
bootstrap programs, 58
CPU (central processing unit), 59
firmware, 58
RAM and ROM, 59
software/programs, 58
Concealment:
Conditional Access Table (CAT), 293
anti-aliasing filters, 97
decimators, 141
differential convertors, 135–6
interpolators, 141
Nyquist rate conversion, 138, 141–2
Nyquist’s theorem, 96
PCM convertors, 137
reconstruction, 98
sigma-DPCM converter, 149
see also ADCs (analog-to-digital convertors); DACs (digital-to-analog convertors); Noise shaping; Quantizing; Quantizing error; Sampling/sampling-rate conversion
Convolution:
CRC see Cyclic redundancy check (CRC) codes
Cross interleaving, 247
CSMA/CD (carrier sense multiple access with collision detect), 272–4
Cyclic redundancy check (CRC) codes, 230–5
DAB (digital audio broadcasting), 21–2, 294–7
DACs (digital-to-analog convertors), 122–9
accuracy considerations, 127–9
clock jitter, 122
dynamic element matching, 124–7
integrated convertors, 123, 125, 128
monolithic convertors, 127
and reconstruction filters, 128
weighted-current convertors, 127
see also Conversion/convertors
DAT (digital audio tape), 299–324
AES/EBU interface/channel status, 307–8
area divided track following (ATF), 309–11, 313–14
sampling rates, 103
SCMS (serial copying management system), 306
specifications and options, 306–7
tape transport mechanism, 305
DCC (digital compact cassette), 320–4
DCT (discrete cosine transform), 85–6, 172, 175–6
Decimators, 141
Density ratio (DR), channel coding, 214, 218
DFT (discrete Fourier/frequency transform), 83–5, 172
Dielectric relaxation, and sample and hold, 104–5
Differential convertors, 135–7
Differential pulse code modulators (DPCMs), 136–7, 148–9
Differentiation, digital, 57
Digital audio:
Digital audio broadcasting see DAB
Digital audio tape see DAT
Digital compact cassette see DCC
Digital faders and controls, 64–8
Digital filters see Filters
Digital logic:
accumulators, 57
adders, half and full, 56
digital differentiation, 57
discrete time integrator, 57
see also Binary systems/signals
Digital mixing/mixers:
DSPs (digital signal processors), 70–1
facilities and operation, 68–70
peak limiting precautions, 68
Digital signal processors (DSPs), audio, 70–1
Digital television audio, 287–9
and the MPEG transport stream, 287–9
program clock reference system, 287
time stamp, 287
see also Nicam 728
Digital-to-analog convertors see DACs
Discrete cosine transform (DCT), 85–6, 172, 175–6
Discrete Fourier/frequency transform (DFT), 83–5, 172
Discrete time integrator, 57
Disk drives see CDs (Compact Discs); Magnetic/hard disk drives; MDs (MiniDiscs)Distortion, with analog audio, 3
Dither:
digitally dithered requantizer, 147–8
digitally generated dither, 119–22
with oversampling, 143
subtractive and non-subtractive, 116
Domains:
DPCMs (differential pulse code modulators), 136–7, 148–9
DR (density ratio), channel coding, 214, 218
DSPs (digital signal processors), audio, 70–1
DVD (Digital Versatile Disc), 404–5
DVTR formats, audio sampling rates, 103
Dynamic element matching, DACs, 124–7
Ear, structure and operation, 26–36
basilar membrane, 29
critical bandwidth, 34
frequency discrimination, 33–6
impulse response, 34
inter-aural intensity difference (IID), 29
organ of Corti, 28
ossicles, 27
pinna, 26
psychoacoustics, 26
Reissner’s membrane, 28
EBU timecode, 350
block boundary editing, 349
edit decision lists (EDLs), 354–5
from random access media, 347–8
insert editing, 356
interleave/reordering problems, 348–9
mastering, 347
with open-reel digital recorders, 357
Eight to fourteen modulation (EFM), 388, 390
Encryption systems, channel coding, 221
Entropy, compression, 161
Error concealment:
Error detection/correction:
CD (Compact Disc), 393–7, 400–1
AES/EBU interface, 254
by trading probabilities, 227
codewords, 227
concealment by interpolation, 225
correction by erasure, 243
cross interleaving, 247
cyclic redundancy check (CRC) codes, 230–5
error avoidance, 224
error bursts, 223
forward error-correction schemes (FECs), 224
interleaving, 15, 244–5, 247, 393–7, 397–8
Expansion/expanders, 157
Eye patterns:
Faders and controls see Digital faders and controls
Faraday effect, 205
FECs (forward error-correction schemes), 224, 280
FFT (fast Fourier transform), with MPEG Layer I, 178
active filters, 101
anti-aliasing filters, 97
for conversion requirements, 99–101
and delay, 71
FIR (finite-impulse response) filters, 74–7
IIR (infinite-impulse response) filters, 74
and impulse response testing, 71
time and frequency domains, 72–4
and transforms, 72
FIR (finite-impulse response) filters, 74–7
Gibb’s phenomenon, 75
Firewire (IEEE 1394–1995), 274–6
Firmware, 58
Forward error-correction schemes (FECs), 224, 280
Frequency division multiplexing (FDM), 268–9
Frequency domain, 25
Frequency response and linearity, 36–7
Frequency and time domains, filters, 72–4
by hard-wired bit shifting, 64
Galois field (GF)/Galois multiplication, 87–9, 237–42
GCR see Group codes/group code recording (GCR) Genlocking, 89
Gibb’s phenomenon, FIR filters, 75
Granulation, 115
Group codes/group code recording (GCR), 218–20
Hard disk drives see Magnetic/hard disk drives
HDLC (High-level Data Link Control), 259
Helical-scan recorders see Rotary head recorders
IIR (infinite-impulse response) filters, 74
Impedance matching, unnecessary use of, 44–5
Integer-ratio conversion, 78
Inter-block prediction, 176
Inter-symbol interference (peak distortion), 203
Interfaces see AES/EBU digital audio interface; MADI (Multi-channel audio digital interface); Optical fibres
Interleaving:
Interpolators, 141
Inverse transforming, 176
ISO/IEC/MPEG organization, 176–7
Isochronous operation, networks, 269
Jitter:
and phase-locked loops, 11
Kaiser-Bessel-derived (KBD) window, 188
Karaoke system, CDs (Compact Discs), 402
Lempel-Ziv-Welch (LZW) lossless codes, 161
Logic see Digital logic
Lossless (predictive) coding, 159–60, 164
Lossy (perceptive) coding, 160, 161–2, 164
LSB (least significant bit), 7–8
MADI (Multi-channel audio digital interface), 259–63
Magnetic field modulation technique, 363–4
data separation and equalization, 206–8
inductive heads, 203
inter-symbol interference (peak distortion), 203
magneto-resistive (MR) heads, 202–3, 321–2
slicing and jitter rejection, 208–13
see also DAT (digital audio tape); Magnetic/hard disk drives; Rotary head recorders
Magnetic/hard disk drives:
digital audio disk system, 342–4
disk rotation aspects, 333
disk structure, 327
exchangeable pack drives, 326
head matrix, 330
head moving servo system, 331–2
reading and writing process, 328–9
sampling rate and playing time, 345
servo-surface disks, 333
thin-film heads, 329
Magneto-optical recording see Optical/magneto-optical recording/ playback
Mar‘Echal criterion, 381
Masking threshold, MPEG Layer I coder, 178
Mastering, editing for, 347
MDCT (modified discrete cosine transform), 172, 183–4
MDs (MiniDiscs):
block diagram, 404
CD comparisons, 364
disk manufacture processes, 383–6
error detection/correction, 400–1
magnetic field modulation technique, 363–4
surface contamination rejection, 366–9
see also Channels/channel coding; optical/magneto-optical recording/ playback
MFM (modified frequency modulation) code, 217–18
MiniDiscs see MDs
Mixing/mixers see Digital mixing/mixers
Modified discrete cosine transform (MDCT), 172, 183–4
Modulation transfer function (MTF), 380–1
MOS (metal oxide semiconductor) RAM, 56–7
Moving-head disk drives see Magnetic/hard disk drives
MPEG, elementary, program and transport streams, 19
MPEG Layer I coder/decoder, 177–81
MPEG Layer II coder/decoder, 181–3
granule encoding, 182
MUSICAM similarities, 181
MPEG Layer III coder/decoder (MP3), 183–5
ASPEC origins, 183
MPEG-2 AAC (advanced audio coding), 185–91
Huffman coding, 191
Kaiser-Bessel-derived (KBD) window, 188
prediction and buffering, 167
scaleable sampling rate (SSR) profile, 186
temporal noise shaping (TNS), 189
MPEG/Audio group, 177
MSB (most significant bit), 7–8
MTF (modulation transfer function), 380–1
Multi-channel rotary head recorders, 314–16
Multiplexing:
application and operation, 62–3
basic concept, 13
FDM (frequency division multiplexing), 268–9
Multiplication, for gain control, 64
arbitration and priority, 270–4
asynchronous operation, 269
communication aspects, 22
CSMA/CD (carrier sense multiple access with collision detect), 272–4
isochronous operation, 269
synchronous operation, 269
carrier frequency, 282
companding process, 284
differentially encoded quadrature phase shift keying (DPQSK), 284
Frame Alignment Word, 284
sampling rate for, 103
NLLs (numerically locked loops), 89–90
NMR (noise to masking ratio), 165–6
Noise:
Noise modulation, and quantizing error, 115
and additive dither, 145
with digitally dithered requantizing, 147–8
one-bit noise-shaping ADCs, 153–5
psychoacoustically optimal noise shaping, 148
Noise to masking ratio (NMR), 165–6
NRZI (Non-Return to Zero Invert) coding, 215
NTSC TV, sampling rate for audio, 102
Numerical Aperture (NA), 381–2
Nyquist’s theorem:
Optical/magneto-optical recording/playback, 204–6
Airy distribution/pattern/disk/function, 379–81
data separation and equalization, 206–8
Faraday effect, 205
magneto-optical recording, 204–6
magneto-optics/thermomagneto-optics, 362–4
Mar‘Echal criterion, 381
media problems, 206
modulation transfer function (MTF), 380–1
Planck’s law, 369
slicing and jitter rejection, 208–13
surface contamination rejection, 366–9
see also CDs (Compact Discs); MDs (MiniDiscs)
Oversampling convertors, 77–8, 101, 138–43
and anti-aliasing, 142
decimators, 141
with digital dither, 143
interpolators, 141
and noise shaping, 149
and Nyquist rate conversion, 138
and signal-to-noise ratio (SNR), 138
Packets and time stamps, 289–90
decode time stamp (DTS), 289–90
packet identification (PID) code, 291, 292–3
packetized elementary stream (PES), 289
PAL TV, sampling rate for audio, 102–3
see also Error detection/correction
PASC (Precision Adaptive Sub-band Coding), 321
PCM (pulse code modulation):
Peak limiting, and digital mixing, 68
Peak program meter (PPM), 45
Peak-to-peak measurement, 40–1
Perceptive (lossy) coding, 160, 161–2, 164
see also Compression/compressors
Perceptual entropy, 166
Phase-contrast microscopy, 361
Phase-locked loops (PLLs), 89–90
Planck’s law, 369
Power spectral density (PSD), 144
PPM (peak program meter), 45
Precision Adaptive Sub-band Coding (PASC), 321
Predictive coding see Lossless (predictive) coding
Product codes, 15–18, 228–9, 245–7
Program clock reference (PCR), 291–2
Program Specific Information (PSI), 292–3
PSD (power spectral density), 144
Psychoacoustically optimal noise shaping, 148
Psychoacoustics, 26
Pulse code modulation see PCM
Quadrature mirror filtering (QMF), 173–4
Quadrature waveforms, 39
Quantizing:
anharmonic distortion, 115
and distortion, 114
granulation, 115
noise modulation, 115
quantizing noise, 114
and transfer function non-linearity, 115
and wordlength shortening, 120
see also Dither
RAID (redundant array of inexpensive disks), 340–2
Ramp integrators, 133
RAMs (random access memories), 54–7, 59
Randomizing technique, channel coding, 220–1
Recording see Magnetic recording; Optical/magneto-optical recording/ playback
Redundancy, and parity, 227
with ATM, 280
Galois field (GF)/Galois multiplication, 237–42
generator polynomial calculations, 247–9
locators and correctors, 235
polynomial division on CD, 394
primitive element, 237
Residual expansion, 134
RLL (run-length-limited) codes, 219, 222
Root mean square measurements, 39–41
rotary-head digital recorders, 21
spliced tape with, 315
stationary head recorder comparison, 299
see also DAT (digital audio tape); Magnetic recording; Multi-channel rotary head recorders
see also Networks
Run-length-limited (RLL) codes, 219, 222
Sampling/sampling-rate conversion:
for CDs, 103
fractional ratio conversion, 79
integer-ratio conversion, 78
interpolation stage, 79
oversampling/sampling convertors, 77–8, 101, 138–43
variable-ratio interpolators, 79–81
see also Conversion
SCMS (serial copying management system), 306
SDH (synchronous digital hierarchy), 276–8
Sigma-DPCM convertors, 149
Signal detection:
Signal-to-noise ratio (SNR), and oversampling, 138
Silos, 61
and quadrature waveforms, 39
Slicing, 5
SNR (signal-to-noise ratio), and oversampling, 138
SONET (synchronous optical network), 276–8
Sound:
frequency response and linearity, 36–7
periodic and aperiodic signals, 25–6
sound pressure level (SPL), 31–2
speed of, 24
wavelength, 24
see also Audio technology; Ear
SPDIF (Sony Philips Digital Interface), 250–1
SPL (sound pressure level), 31–2
Splice handling:
Stationary head recorders:
MPEG Layer I coder, 178
synchronous operation, networks, 269
Television:
Temporal noise shaping (TNS), 189
Thermomagneto-optics see Optical/magneto-optical recording/ playback
Time compression and expansion see Compression; Expansion
Time division multiplexing (TDM), 268–9
Time and frequency domains, 25
Time stamps see Packets and time stamps
Timecodes, EBU and SMPTE, 350
TNS (temporal noise shaping), 189
Track-hold circuits, 103–5, 129
Transforms:
DCT (discrete cosine transform), 85–6, 172, 175–6
DFT (discrete Fourier/frequency transform), 83–5, 172
FFT (fast Fourier transform), 178
for filters, 72
inverse transforming, 176
Transmission channels:
Transport stream concept:
Two’s complement system, 49–52
Variable length coding, 163
Variable-ratio interpolators, 79–81
VCAs (voltage controlled amplifiers), 64
VCOs (voltage-controlled oscillators), and Phase-locked loops, 89, 211–13
VCXOs (voltage-controlled crystal oscillators), 291–2
Volume unit (VU) meter, 45
Wavelength, 24