AN307

4

Rev. 0.2

//If half of the filter has been filled with noise level values,

//calculate the average noise level

SET AverageFreq to ( StartingFreq +

( i - ( FilterWidth / 2 ) ) * ChannelSpacing )

SET NewAverage to 0

SET FilterWeighting to 12

//Multiply the noise levels by with filter weight coefficients

FOR each j = 0 to FilterWidth

SET Index to ( ( j + FilterPointer ) MODULUS FilterWidth )

SET NewAverage to ( NewAverage +

( FilterData at Index ) * ( FilterCoefficients at j ) )

IF ( FilterData at Index ) = 0

SET FilterWeighting to

( FilterWeighting - ( FilterCoefficients at j ) )

SET NewAverage to ( NewAverage / FilterWeighting )

IF NewAverage < ( Minima at CurrentBand )

SET ( Minima at CurrentBand ) to NewAverage

//Record the lowest noise level in the current band