VoIP Voice and Fax Signal Processing

INDEX

Absolute category rating (ACR):

defined, 481–482

voice quality measurements, 429

Acknowledgement (ACK) signal:

call wait ID flow, PSTN, 194–196

call wait ID in VoIP, 197–198

Acoustic echo canceller (AEC), 120–123

Acoustic interfaces, voice over internet protocol, 26–27

Active monitoring, voice quality objective measurements, 429–434

Adaptation filtering algorithms, echo cancellation, 132–137

adaptive transversal filter, LMS, 133–135

affine projection algorithm, 137–138

block NLMS algorithm, 135–136

control functions, 137–144

leaky LMS, 136

RLS/affine projections, 136–137

RLS disadvantages, 137

Adapter components, voice over internet protocol, 28–31

IP PBX adapter, 40

residential gateway, 33–35

voice and fax software, 31–33

voice flow, 31

Adaptive differential pulse code modulation (ADPCM):

cordless phones, 455

voice compression, 60–61

Adaptive jitter buffer (AJB):

algorithms overview, 230–239

basic properties, 223–228

defined, 477

implementation guidelines, 239–241

non-talk-spurt-based adjustments, 226, 233–234

playout-based timing reference and talk-spurts, 231–232

spike playout, 232–233

talk-spurt-based adjustments, 225–226

voice flow and delay variations mapping, 227–228

voice quality estimation:

packet flow impediments, 451

silence zone utilization, 451–452

Adaptive multirate (AMR) codec:

packet-loss compression, 109

transcoding and conference operations, 454–455

voice compression, 68

wideband (AMR-WB) coded, 69–70

Adaptive transversal filter with LMS, echo cancellation, ...