Document Type
Thesis
Date of Award
5-31-1989
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical Engineering
First Advisor
Fidel Morales-Moreno
Second Advisor
Joseph Frank
Third Advisor
Chung H. Lu
Abstract
In this thesis convolutional coded continuous-phase frequency shift keying (CPFSK) is studied.
CPFSK which is a subclass of continuous phase modulation ( CPM ) is a constant amplitude digital modulation scheme with very good spectral characteristics.
A new method, called matched encoding, that combines convolutional codes and CPFSK is studied. With the maximum free Euclidean distance as the optimization criterion, the best combined coded schemes were found for the same rate of the codes and given total number of states in the optimum decoder.
A different method which was suggested by Rimoldi[7], called the decomposition method, is also described in this thesis. We compare this method with the matched encoding method for various modulation indices.
Numerical results were searched here for rate 1/2 convolutional codes combined with binary CPFSK with modulation index h equal to 1/2 and quaternary CPFSK with modulation indices h equal to 1/2 and 1/4.
We also compare our results with the decomposition method. We found that the best results strongly depend on the model; for some special modulation indices the decomposition method can get better results but for some other modulation indices the results are even worse than the traditional method[4]. The performance of the codes obtained by the matched encoding method in every case equal or surpass the performance of the codes obtained by the traditional method. Some of the best codes are catastrophic however the combined encoding and modulation schemes are not catastrophic.
Recommended Citation
Yang, Hsinhsyong, "Efficient design of trellis coded CPFSK" (1989). Theses. 2954.
https://digitalcommons.njit.edu/theses/2954
