Error-rate measurements for S.F.S.K. with band limitation

The error rates of the modulation method in data transmission called sinusoidal frequency-shift keying (SFSK) with matched-filter detection were measured under restricted bandwidth conditions. Error rates were determined using a receiver filter only, as well as both a transmitter and receiver filter, to calculate the effects of varying degrees of band limitation to SFSK error performance. The ratio of the energy per bit of the undistorted SFSK waveform (Eb) to No, the one-sided noise spectral density of the Gaussian noise, was found, and the Eb/No degradations from the ideal binary phase-shift-keyed performance were determined as a function of the degree of band limitation. It is shown that for the same bandwidth parameter, the Gaussian filter with good phase linearity and gentle roll-off offers better error performance than the 4th-order Butterworth filter that simulated channels with phase nonlinearity.