CVC® or Clear Voice Capture, is CSR's own DSP software technology for enhancing audio quality on wireless products. A modular suite of algorithms includes acoustic echo cancellation and noise suppression that can be applied in a granular fashion and tuned to suit the application. CSR has been shipping noise and echo suppressing versions of CVC for many years with ROM-based headset designs. An enhanced fifth-generation algorithm is provided for BC6140 and BC6150:

• BC6140 provides single-microphone audio enhancement algorithm offering up to 18dB of stationary noise reduction.
• BC6150 provides a dual-microphone audio enhancement algorithm offering more than 30dB of dynamic noise reduction.

There are two major additions to the latest algorithm suite:

Packet loss concealment/bit error concealment
This error concealment module improves the quality of received audio by removing pops and clicks caused by radio interference such as from WiFi. The spectral restoration improves audio quality and provides a better signal for subsequent CVC processing to work with.

Near-end audio enhancement
Received audio quality is also greatly enhanced by a number of software modules in the reception signal processing chain including:

• Noise suppression - a single channel module for reducing the impact of stationary noise in received speech. This improves conversational performance and significantly boosts SNR for subsequent processing blocks.
• Adaptive Equalisation - adjusts the received speech spectrum to exploit sensitive areas of human hearing without excessive amplification. Frequency content adapts depending on ambient noise - enabling conversations in harsh environments.
• Equalisation - multiple parametric equalization stages for compensation of the spectral characteristics of the loudspeaker.
• Automatic gain control - provides amplitude smoothing and compensation for variances of speech level from different sources.

Note that this is not third-party software. There are no extra license fees to pay - the cost of the chip includes the audio enhancement technology.

Applications
CSR offers CVC as integrated elements of development tools and ready-to-use solutions for common Bluetooth applications. Examples include:
The BC6100 range provides a mid-level headset product range and two solutions that introduce active audio quality enhancement.	Groundbreaking BlueTunes ROM slashes the cost of building advanced Bluetooth® stereo wireless headphones for music and audio applications.	RoadRunner Plug'n'Talk is a ready to apply Bluetooth design for automotive applications - with echo cancellation and noise suppression algorithms optimised for the automobile cabin.