  We design new continuous phase modulation (CPM) formats which are based on
the combination of a proper precoder with binary input and a ternary CPM. The
proposed precoder constrains the signal phase evolution in order to increase
the minimum Euclidean distance, and to limit the bandwidth expansion due to the
use of a ternary CPM. The resulting schemes are highly spectrally efficient and
outperform classical binary and quaternary formats in terms of coded and
uncoded performance.
