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QAM Quadrature Amplitude Modulation. Sigit Kusmaryanto http://sigitkus.lecture.ub.ac.id. Gambar-1 : Bagan Pemancar QAM. Modulator AM. 2-4 level Converter. fb/2. QAM. Oscilator lokal. I. Data. Pembagi Data. fb. . Bine r. Q. 90º. fb/2. 2-4 level Converter. Modulator AM.
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QAMQuadrature Amplitude Modulation Sigit Kusmaryanto http://sigitkus.lecture.ub.ac.id
Gambar-1 : Bagan Pemancar QAM Modulator AM 2-4 level Converter fb/2 QAM Oscilator lokal I Data Pembagi Data fb Biner Q 90º fb/2 2-4 level Converter Modulator AM
Gambar-2 : Pola Konstelasi Sinyal Q • • • • • • • • • • • • • • • • I
Gambar-3 : Spektrum QAM Pita sisi bagian bawah Pita sisi bagian atas f (Hz) fc - B fc fc + B BT = 2B
Gambar-4 : Diagram Modem QAM Pentransmisi Cos ct ai Pembentukan Masukan biner Luaran QAM Penyangga dan pengkode 1/T R bit/detik 1/T simbol/detik bi Pembentukan T = n/R ( Menyimpan n bit ) Sin ct Penerima Luaran-luaran biner Masukan QAM Filter lolos pita Pengurai kode Penemu-penemu sinkron R bit/detik 1/T 1/T simbol/detik
Gambar-5 : Eye Patterns ( Pola Mata ) Normal Noise yang berlebihan
REFERENSI • Feher, Kamilo .1987. Advanced Digital Communication . USA : prentice-Hall • Haykin, Simon . 1989. An Introduction to Analog and Digital Communications . Singapore : John Willey • Lathi , B . P . 1983 .Modern Digital and Analog Communication System . USA : Holt – Saunders. • Schwartz , Mischa . 1986 . Transmisi , Informasi , Modulasi dan Bising . Terjemahan Srijatno W., Ph.D. Jakarta : Erlangga. • Smith , David R . 1985 . Digital Transmission Systems . New york :Van Nostrand Reinhold Company . • Stallings , William .1991 . Data and Computer Communications. Singapore : Maxwell Macmilan International Edition. • Roddy , Denis and John Coolen . 1985 . Electronic Communication . New Delhi : Prentice-Hall.