Location of noise rms bits in the DLPF processing


        There are various stages in the pdev processing  where shift values need to be set (hr_shift, pshift). These need to be set to maintain sufficient  bits on the noise while retaining the maximum dynamic range (probably a redundant statement!!). To measure this,  time domain data was taken with a noise source input. The setup was:
    The dlpf operations are a multiply and accumulate. The number of additions is equal to the decimation specified. The rms noise should increase as the square root of the number of additions.

    The plots show the rms values from the various decimations (.ps) (.pdf):


processing: x101/070924/chkrms.pro

<- page up