Spectral Occupancy of Digital Angle-Modulation Signals

Abstract

The spectral or band occupancy of an rf signal is often defined as the bandwidth that contains a specified fraction (usually 99 percent) of the modulated rf power. The band occupancy of binary and quaternary psk signals with and without rf filtering and with modulation pulses of several shapes has been evaluated and the results presented in graphical and tabular form. For a binary fsk signal with phase deviation of ±π/2, sometimes called an fm‐psk signal, numerical values of the spectral occupancy with rectangular and raised‐cosine signaling have been obtained and the results given in graphical form. For a binary psk signal with signaling rate 1/T and with arbitrary baseband pulse shaping, we have derived a lower bound on the fraction of the continuous power contained outside any given band, but have not been able to get a bound on the total band occupancy. However, for an fm‐psk signal, a lower bound on the total band occupancy has been derived, and it is shown that the value of this lower bound for 99‐percent power occupancy is 1.117/T. The 99‐percent power occupancy bandwidth of an fm‐psk signal is 1.170/T with rectangular signaling and 2.20/T with raised‐cosine signaling.

Spectrum Occupancy of Pulsed FSK

“…However, the (2) wide sense stationary process cannot be a finite energy process since the energy of such a process must be a function of time. In what follows, a(t) is a determinate pulse, and, thus, the result is an energy spectrum.…”

“…1,2). The results given subsequently have been based on a 512 point FFT with 16 points per modulation interval.…”

“…1,2). Spectrum occupancy may be defined as that bandwidth containing a predetermined fraction of the radiated power (0.99, 0.999, for example).…”