Bandlimiting Distortionless FSK Filters

E. D. Sunde has found the bandlimiting filters for frequency-shift-keyed (FSK) signals satisfying Nyquist's first criterion. The frequency difference is equal to the signaling speed. The bandlimiting filters for FSK that produce signals to satisfy Nyquist's second criterion are determined here. The minimum bandwidth is equal to the signaling speed. The bandlimiting filter that produces signals satisfying both Nyquist critera for FSK is also determined. The minimum bandwidth required is twice the signaling speed.