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Teknik Modulasi Pertemuan 07 Matakuliah: H0484/Jaringan Komputer Tahun: 2007.

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Presentation on theme: "Teknik Modulasi Pertemuan 07 Matakuliah: H0484/Jaringan Komputer Tahun: 2007."— Presentation transcript:

1 Teknik Modulasi Pertemuan 07 Matakuliah: H0484/Jaringan Komputer Tahun: 2007

2 Bina Nusantara Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Menjelaskan teknik modulasi

3 Bina Nusantara Outline Materi Teknik Modulasi Modulasi analog Modulasi digital

4 Bina Nusantara Encoding Techniques Analog data, carrier analog signal Digital data, carrier analog signal Analog Modulation Analog data, carrier digital signal Digital Modulation Digital data, carrier digital signal Encoding

5 Bina Nusantara Analog Data, Analog Signals Why modulate analog signals? – Higher frequency can give more efficient transmission – Permits frequency division multiplexing Types of modulation – Amplitude – Frequency – Phase

6 Bina Nusantara Analog Modulation

7 Bina Nusantara Modulasi Tujuan: Mengubah sinyal komputer yang digital menjadi sinyal analog yang diperlukan oleh saluran komunikasi. Memperbesar jarak jangkau sinyal informasi. Modem merupakan perangkat keras untuk kedua proses ini LST/FASKD/CINQ

8 Bina Nusantara Type Modulasi Digital /Analog

9 Bina Nusantara Modulation Techniques

10 Bina Nusantara Frequency Shift Keying Most common form is binary FSK (BFSK) Two binary values represented by two different frequencies (near carrier) Less susceptible to error than ASK Up to 1200bps on voice grade lines High frequency radio Even higher frequency on LANs using coax

11 Bina Nusantara Phase Shift Keying Phase of carrier signal is shifted to represent data Binary PSK – Two phases represent two binary digits Differential PSK – Phase shifted relative to previous transmission rather than some reference signal

12 Bina Nusantara Quadrature PSK More efficient use by each signal element representing more than one bit – e.g. shifts of  /2 (90 o ) – Each element represents two bits – Can use 8 phase angles and have more than one amplitude – 9600bps modem use 12 angles, four of which have two amplitude

13 Bina Nusantara 4-PSK Constellation

14 Bina Nusantara Quadrature Amplitude Modulation QAM used on asymmetric digital subscriber line (ADSL) and some wireless Combination of ASK and PSK Logical extension of QPSK Send two different signals simultaneously on same carrier frequency – Use two copies of carrier, one shifted 90 ° – Each carrier is ASK modulated – Two independent signals over same medium – Demodulate and combine for original binary output

15 Bina Nusantara 4-QAM and 8-QAM

16 Bina Nusantara PULSE AMPLITUDE MODULATION Pulse amplitude modulation has some applications, but it is not used by itself in data communication. However, it is the first step in another very popular conversion method called pulse code modulation.

17 Bina Nusantara Pulse Code Modulation (PCM)

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