We have something new and exciting for everyone using the FM radio receiver of VS1005, namely the FM Stereo Radio Noise Killer!
Because of the way stereo information is transmitted on FM radio, stereo reception is always more suscept to white noise and other artifacts than mono. A way to reduce or remove the noise is to either dampen the stereo effect at the receiver, or to turn FM reception completely to mono. But now there is a new solution. The FtNoiseKiller package offers an adaptive FM stereo radio noise killer that removes the noise but not your stereo image!
As an example of the effectiveness of this algorithm, I have included a real-life sample recording of FM stereo reception, both as it was received as well as after running it through the noise killer. The recording is from a relatively strong channel with normal stereo background noise, but also a nasty tone around 6 kHz. It shouldn't be too difficult to spot the difference between the original and processed version. For details on how to use the noise killer, read the README.TXT file of the package. NOTE! You need to listen to the files through stereo earphones or stereo speakers! A mobile phone or tablet mono speaker will NOT show any difference!
In addition to the noise killer driver, I have attached a new version of the RDS Radio receiver which will now automatically start in stereo mode if it recognizes the noise killer in the stdaudioin handle. To disable the noise killer, push '0' (zero), and to re-enable it, push '5' (or '4' or '3' to turn the noisekiller up if reception is poor).
Please note that this noise removal algorithm specifically targets stereo FM radio, and is not usable for general purpose noise reduction. We will later release a version that targets microphone background noise.
Discussion about writing software for VS1005 and the VSOS Operating System. Also posts about VS1005-related hardware design and device drivers should be posted here.
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- 30 second FM radio reception sample, unprocessed.
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- 30 second FM radio reception sample, processed with the noise killer.
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- Noise killer. See README.TXT for details.
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- RDS Radio v1.05 that can play in stereo and control the noise killer. See README.TXT for details.
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Good signatures never die. They just fade away.