Title :
Design and implementation of a π/4-DQPSK transmitter for maritime VHF digital communications
Author :
Kim, Seung-Geun ; Sung, Soyoung ; Yun, Chanho ; Lim, Young-Kon
Author_Institution :
Ocean Syst. Eng. Res. Dept., KORDI, Daejeon, South Korea
Abstract :
In this paper, a design and implementation of π/4-DQPSK transmitter for the exchange of digital data and e-mail between shore and ship stations and/or between ship stations on the one of the maritime mobile service VHF channels are described. The designed transmitter is composed of a baseband modulator, a baseband-to-RF band up-converter with Cartesian feedback, a power amplifier, and a coupler. Base on the design, the π/4-DQPSK transmitter is implemented. The implemented transmitter is composed two boards. One is implemented for system control, external interface, baseband modulation and mixing with Cartesian feedback. The other is implemented for power amplifier, coupler, and generation of required DC voltages. The emitted power spectrum of implemented transmitter is measured using spectrum analyzer through 30 dB attenuator. The measured results show that the in-band signal power is slightly reduced and the out-of-band signal power is additionally reduced more than 30 dB when the Cartesian feedback loop is used.
Keywords :
VHF radio propagation; differential phase shift keying; electronic data interchange; electronic mail; marine communication; mobile radio; quadrature phase shift keying; Cartesian feedback loop; DQPSK transmitter; baseband modulation; baseband modulator; baseband-to-RF band up-converter; coupler; digital data exchange; e-mail exchange; external interface; inband signal power; maritime VHF digital communications; maritime mobile service VHF channels; out-of-band signal power; power amplifier; power spectrum; required DC voltages; ship stations; spectrum analyzer; system control; Baseband; Couplers; Marine vehicles; Modulation; Power amplifiers; Radio transmitters;
Conference_Titel :
OCEANS, 2011 IEEE - Spain
Conference_Location :
Santander
Print_ISBN :
978-1-4577-0086-6
DOI :
10.1109/Oceans-Spain.2011.6003639