CPM; Digital Communications; Modulation; ternary FM
It is well-known that binary continuous phase modulation (CPM) waveforms can be exactly represented as a pulse amplitude modulation (PAM) waveforms. This has also been shown for nonbinary CPM waveforms with even-sized symbol alphabets. In this paper we show how this is also accomplished for ternary CPM waveforms. We focus the development on signals with shorter frequency pulses, since these cases have the most practical value in designing reduced-complexity detectors. However, we also show the pattern by which these results can be extended to arbitrary frequency pulse durations and also to arbitrary odd-sized symbol alphabets, although little practical value is perceived in either of these extensions. We conclude with a thorough application of the results using the ternary CPM waveform SOQPSK-TG, which is an aeronautical telemetry standard.