MSK Modulation for Multiple Access

Abstract

Minimum Shift Key (MSK) is known to possess desirable qualities, such as low spectral sidelobes and dual channels quadrature in both phase and sampling time. It is also a robust signal, tolerant to considerable amplitude limiting and spectral filtering. MSK modulation of Pseudo Noise (PN) sequences can be used to effect a communication network with multiple access, which can be of either random or assigned synchronism. Such a network exhibits resistance to jamming by external signals in the form of processing gain. This approach leads to multiple access terminal designs which are coherent, with a single RF front end which is not phase locked. A particularly effective implementation outlined in this paper utilizes a Charge Coupled Device (CCD) filter matched to the PN sequence as the basic correlating device for multiple access.