VAD/CNG - Voice Activity Detector / Comfort Noise Generator

Telephony by Adaptive Digital

ADT VAD / CNG C54x , C55x , C64x , C64x +

DESCRIPTION

Adaptive Digital’s VAD/CNG .pdf software performs voice activity detection and comfort noise generation. It is used in systems that used reduced bandwidth channels during silent or non-voiced portions of a conversation. The VAD algorithm is used at the transmit side of a communication link. The VAD determines whether or not speech is present in the outbound signal. If speech is not present, the VAD algorithm determines the level of the background noise. The background noise level is transmitted to the opposite end of the link in place of the speech signal. The noise level requires little channel bandwidth and only needs to be transmitted when the background noise level changes. The CNG algorithm runs at the receive side of the link. When speech is not present, the CNG algorithm generates a noise signal at the level sent from the transmit side.

Applications include Voice-Over-Packet, Satellite, and other digital voice applications.

FEATURES

  1. Functions are C-callable.
  2. Multi-channel capable
  3. Can be used with all types of speech coding
  4. Spectrally shaped noise generation

AVAILABILITY

ADT VAD/CNG is available on the TMS320™ DSP Family

C54x™DSP, C55x™DSP, & C64x™DSP Generations

SPECIFICATIONS

VAD/CNG C54x

All Memory usage is given in units of 16-bit word.

SOFTWARE
MIPs (Peak)
Program Memory
Data Memory
Per-Channel Data Memory
VAD
0.36
423
291
26
CNG
0.47

Last update: 11/13/2004

VAD/CNG C55x

All Memory usage is given in units of byte.

SOFTWARE
MIPs (Peak)
Program Memory
Data Memory
Per-Channel Data Memory
VAD
0.28
815
582
52
CNG
0.29

*Loading assumes a 2-frequency signal

Last update: 01/23/2005

VAD/CNG C64x

All Memory usage is given in units of byte.

SOFTWARE
MIPs (Peak)
Program Memory
Data Memory
Per-Channel Data Memory
VAD
0.19
1568
584
64
CNG
0.15

Last update: 10/16/2007

VAD/CNG C64x +

All Memory usage is given in units of byte.

SOFTWARE
MIPs (Peak)
Program Memory
Data Memory
Per-Channel Data Memory
VAD
0.17
1472
584
64
CNG
0.15

Last update: 10/16/2007

 

FUNCTION

VAD_ADT_vadInitialize (…) Initializes the VAD and CNG modules

VAD_ADT_vad (…) Executes voice activity detector

CNG_ADT_cng (…) Executes comfort noise generator

 

 

 

PRODUCTS