Sistem Telekomunikasi, Sukiswo, ST, MT Sukiswo sukiswok@yahoo.com Digital Modulation Sukiswo sukiswok@yahoo.com Sistem Telekomunikasi, Sukiswo, ST, MT

Sistem Telekomunikasi, Sukiswo, ST, MT Outline ASK FSK PSK Sistem Telekomunikasi, Sukiswo, ST, MT

Sistem Telekomunikasi, Sukiswo, ST, MT Digital Modulation Three basic forms of digital modulation Analog Digital AM Amplitude ASK FM Frequency FSK PM Phase PSK Sistem Telekomunikasi, Sukiswo, ST, MT

Sistem Telekomunikasi, Sukiswo, ST, MT Amplitude Shift Key 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 1 0 1 1 1 t (logic 1) (logic 0) Sistem Telekomunikasi, Sukiswo, ST, MT

Amplitude Shift Keying[1] Sistem Telekomunikasi, Sukiswo, ST, MT Amplitude Shift Keying[1] The ASK waveform for one pulse (logic 1) In order to find an Energy Spectrum of The Autocorrelation technique is used Delay Energy Spectrum Therefore Energy Spectrum of ASK sinc2 function Sistem Telekomunikasi, Sukiswo, ST, MT

Power Spectral Density Sistem Telekomunikasi, Sukiswo, ST, MT Power Spectral Density Detection of ASK : detect present (logic 1) or of the carrier absent (logic 0) Sistem Telekomunikasi, Sukiswo, ST, MT

Frequency Shift Keying Sistem Telekomunikasi, Sukiswo, ST, MT Frequency Shift Keying 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 1 0 1 1 1 t Output for 1 Output for 0 Sistem Telekomunikasi, Sukiswo, ST, MT

Power Spectral Density Sistem Telekomunikasi, Sukiswo, ST, MT Power Spectral Density Frequency separation Note: To prevent significant overlapping of the bandpass of two filters in detection process frequency separation Data rate Sistem Telekomunikasi, Sukiswo, ST, MT

Power Spectral Density[1] Sistem Telekomunikasi, Sukiswo, ST, MT Power Spectral Density[1] The Actual shape of Power Spectral Density of FSK Detection of FSK Bandpass Filter is used to detect f1 (1) and f2 (0) In general for frequency separation; ; or where m is an integer Sistem Telekomunikasi, Sukiswo, ST, MT

Sistem Telekomunikasi, Sukiswo, ST, MT Phase Shift Keying 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 1 0 1 1 1 t ~ Sistem Telekomunikasi, Sukiswo, ST, MT

Power Spectral Density Sistem Telekomunikasi, Sukiswo, ST, MT Power Spectral Density Sistem Telekomunikasi, Sukiswo, ST, MT

Detection of PSK Phase Reversal Key (PRK) Sistem Telekomunikasi, Sukiswo, ST, MT Detection of PSK Phase Reversal Key (PRK) Since information is in the phase, only synchronous detection is possible Receiver: To data detection Matched filter detection carrier Synchronize (coherent) Local oscillator e.g. Crystal oscillator known as Voltage Control Oscillator VCO Sistem Telekomunikasi, Sukiswo, ST, MT