Roundoff Noise Analysis for FSK Signals in White Noise Represented as Signed Power-of-Two Numbers

Multiplierless filtering is very attractive for digital signal processing, for the coefficient multiplier is the most complex and the slowest component. An alternative way to achieve multiplierless filtering other than designing digital filters with signed power-of-two (SPT) coefficient values is to round each input data to a sum of a limited number of SPT terms. However, when signals are rounded to SPT numbers, a roundoff noise representing the roundoff error is introduced. This paper presents an analysis for the roundoff noise produced when a frequency shift keying (FSK) signals in white noise is rounded to SPT terms. Formulae to compute the rounded signals´ SNR are established.