Title :
Spectral pollution in TDMA: digital FM and P/4-QPSK experimental study and CAD improvement
Author :
Qi, Yusheng ; Wu, Gene ; Yang, Jiashi ; Feher, Kamilo
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., California Univ., Davis, CA, USA
Abstract :
Spectral pollution or spectral spreading of burst TDMA (time division multiple access) digital FM and π/4-QPSK (quadrature phase shift keying) systems is studied by hardware experimental methods and computer simulation. The effects of rectangular, linear, and raised cosine ramp on/off switching are examined on two prototypes for different gating rates, duty cycles, transmitter-filter roll-off factors, and ramp on/off times. The measured results agree with computer simulation and indicate that the adjacent channel interference (ACI) caused by burst operation in TDMA π/4-QPSK is significantly reduced by raised cosine switching in comparison with other switchings
Keywords :
digital radio systems; frequency modulation; interference (signal); mobile radio systems; phase shift keying; time division multiple access; ACI; CAD improvement; TDMA π/4-QPSK; adjacent channel interference; burst TDMA; digital FM; duty cycles; gating rates; linear switching; mobile radio; quadrature phase shift keying; raised cosine ramp on/off switching; ramp on/off times; rectangular switching; spectral pollution; spectral spreading; time division multiple access; transmitter-filter roll-off factors; Computer science; Computer simulation; Filters; Frequency modulation; Hardware; Land mobile radio; Pollution; Prototypes; Radio transmitters; Time division multiple access;
Conference_Titel :
Vehicular Technology Conference, 1991. Gateway to the Future Technology in Motion., 41st IEEE
Conference_Location :
St. Louis, MO
Print_ISBN :
0-87942-582-2
DOI :
10.1109/VETEC.1991.140612
