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Digital Modulation

Digital Modulation. oleh Risanuri Hidayat. Digital Modulation. Three basic forms of digital modulation Analog Digital AM Amplitude ASK FM Frequency FSK PM Phase PSK. 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 1 0 1 1 1. t. t. (logic 1). (logic 0). Amplitude Shift Key.

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Digital Modulation

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  1. Digital Modulation oleh Risanuri Hidayat

  2. Digital Modulation Three basic forms of digital modulation Analog Digital AM Amplitude ASK FM Frequency FSK PM Phase PSK Digital Modulation

  3. 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 1 0 1 1 1 t t (logic 1) (logic 0) Amplitude Shift Key Digital Modulation

  4. The ASK waveform for one pulse (logic 1) In order to find an Energy Spectrum of Energy Spectrum The Autocorrelation technique is used Delay sinc2 function Therefore Energy Spectrum of ASK 0 Amplitude Shift Key[1] Digital Modulation

  5. Detection of ASK : detect present (logic 1) or of the carrier absent (logic 0) Power Spectral Density Digital Modulation

  6. 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 1 0 1 1 1 t t t t Output for 1 Output for 0 Frequency Shift Key Digital Modulation

  7. 0 Frequency separation Note: To prevent significant overlapping of the bandpass of two filters in detection process frequency separation Data rate Power Spectral Density Digital Modulation

  8. 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 ; Power Spectral Density[1] Digital Modulation

  9. 1 1 1 1 1 0 1 0 0 0 1 1 0 1 0 1 0 0 1 0 1 1 1 t t ~ ~ Phase Shift Key Digital Modulation

  10. Power Spectral Density Digital Modulation

  11. Since information is in the phase, only synchronous detection is possible Receiver: To data detection Matched filter detection carrier Synchronize (coherent) carrier Local oscillator e.g. Crystal oscillator known as Voltage Control Oscillator VCO Detection of PSKPhase Reversal Key (PRK) Digital Modulation

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