PRELIMINARY
CYW43438
11.9 Audio Features
A number of features are implemented in the CYW43438 to provide the best possible audio experience for the user.
■ Mono/Stereo Blend or Switch—The CYW43438 provides automatic control of the stereo or mono settings based on the FM signal
carrier-to-noise ratio (C/N). This feature is used to maintain the best possible audio SNR based on the FM channel condition. Two
modes of operation are supported:
❐ Blend: In this mode, fine control of stereo separation is used to achieve optimal audio quality over a wide range of input C/N. The
amount of separation is fully programmable. In Figure 28, the separation is programmed to maintain a minimum 50 dB SNR across
the blend range.
❐ Switch: In this mode, the audio switches from full stereo to full mono at a predetermined level to maintain optimal audio quality.
The stereo-to-mono switch point and the mono-to-stereo switch points are fully programmable to provide the desired amount of
audio SNR. In Figure 29, the switch point is programmed to switch to mono to maintain a 40 dB SNR.
Figure 28. Blending and Switching Usage
Input C/N (dB)
Figure 29. Blending and Switching Separation
Input C/N (dB)
Document Number: 002-14796 Rev. *K
Page 49 of 101
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