Low power method for demodulation of continuous phase modulated (CPM) waveforms

Abstract

CPM waveforms, which are documented in MIL-STD-188-181B, are typically demodulated in superheterodyne receivers. This paper provides an outline for an alternate method of demodulation. The pulse count demodulation scheme is typically used as a method for demodulation of FM voice signals. The pulse count demodulator does not require fast A/D converters or automatic gain control anywhere in the receive path of the radio. Thus, the receive radio architecture can be designed without these components, decreasing the power requirements and size of the RF portion of the receiver. This paper investigates the performance characteristics of the CPM signal as demodulated through the pulse count demodulator. Some analysis is performed on the extent of the limitations in amplitude and phase accuracy and resolution. The design of the PCD is discussed and this paper provides the simulated results that represent the ultimate performance of the CPM waveform as demodulated through the pulse count demodulator.