Noise Suppression Voice Quality Enhancement Algorithm

Telephony by Adaptive Digital

ADT NOISE SUPPRESSION

DESCRIPTION

The Adaptive Digital noise suppression software reduces background noise that is present in speech signals during periods between speech periods, but not during the actual speech periods. This is a low-MIPS, low-complexity alternative to noise reduction, which reduces noise during speech periods also.

Algorithm Version CPU Utilization Memory Delay SNR Improvement Frequency / Time Based
Noise Reduction High High Moderate Yes Frequency
Noise Suppression Low Low None No Time

The user can configure either version’s cancellation settings to be more or less aggressive. Less aggressive settings reduce noise by a moderate amount while more aggressive settings reduce noise by a greater degree.

One might wonder why a system would be configured with a less aggressive setting. There are a few reasons. One reason is that a very aggressive setting can result in loss of desired signal. Another reason is that, in the case of the low complexity version, an aggressive setting will cause an accentuated difference between the noise level during speech and the noise level when speech is not present. The transitions between speech and no speech may become more objectionable with the more aggressive setting.

Data sheet - pdf

FEATURES

  1. Functions are C-callable.
  2. Multi-channel capable
  3. Completely re-entrant (Channel can interrupt any Channel, any time)
  4. Can be integrated with echo cancellers, VOX, and tone detection/regeneration.
  5. Programmable parameters

AVAILABILITY

ADT Noise Reduction is available on the TMS320™ DSP Family

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

SPECIFICATIONS

Noise Reduction C55x

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

Function MIPS (Peak) Program Memory Data Memory Per-channel Data Memory
NS
0.3
400
42
 12

Noise Reduction C55x

All Memory usage is given in units of byte.

Function MIPS (Peak) Program Memory Data Memory Tables Per-channel Data Memory
NS
0.35
1012
384
4332
 108

Noise Reduction C64x

All Memory usage is given in units of byte.

Function MIPS (Peak) Program Memory Data Memory Per-channel Data Memory
NS
0.2
2400
84
 24

Noise Reduction ARM

All Memory usage is given in units of byte.

Function MIPS (Peak) Program Memory Data Memory Per-channel Data Memory
NS
1.0
2400
84
 24

FUNCTION

NS_ADT_init( . . .)                  Initiates a channel of Noise Suppression

NS_ADT_reduce( . . . )           Executes Noise Suppression


APPLICATIONS

Standard noise reduction is an excellent choice for applications with high background noise environments such as mobile phones, speakerphones, hands-free phones, and defense communication systems. It is also useful when used in conjunction with voice recognition to increase accuracy.

Low Complexity noise reduction is an excellent choice for wireline telephony and conferencing.