The following resources come from the 2009/10 BEng (Hons) in Digital Communications & Electronics (course number 2ELE0064) from the University of Hertfordshire. All the mini projects are designed as level two modules of the undergraduate programmes. The objective of this module is to have built communication links using existing AM modulation, PSK modulation and demodulation blocks, constructed AM modulators and constructed PSK modulators using operational function blocks based on their mathematical expressions, and conducted simulations of the links and modulators, all in Simulink®.

1. Mini Project – Communication Link Simulation Digital Modulation Techniques Author: University of Hertfordshire Date created : Date revised : 2009 Abstract The following resources come from the 2009/10 BEng ( Hons ) in Digital Communications & Electronics (course number 2ELE0064) from the University of Hertfordshire. All the mini projects are designed as level two modules of the undergraduate programmes. The objective of this module is to have built communication links using existing AM modulation, PSK modulation and demodulation blocks, constructed AM modulators and constructed PSK modulators using operational function blocks based on their mathematical expressions, and conducted simulations of the links and modulators, all in Simulink®. Use Matlab®/ Simulink® to design a communication link for AM audio broadcasting. The message signal is a mono audio signal although you may not be able to transmit the full audio frequency range that is normally required for high quality sound. In addition to the resources found below there are supporting documents which should be used in combination with this resource. Please see: Mini Projects - Introductory presentation. Mini Projects - E-Log. Mini Projects - Staff & Student Guide. Mini Projects - Standard Grading Criteria. Mini Projects - Reflection. You will also need the ‘Mini Project- Communication Link Simulation’ text file and the lecture presentation on ‘Channels and Noise’. © University of Hertfordshire 2009 This work is licensed under a Creative Commons Attribution 2.0 License .

6. Types of modulation Modulation techniques for analogue signals Modulation techniques for digital signals

9. Digital Modulation - Carrier In digital modulation, one of the properties of the carrier (amplitude, frequency or phase) is changed according to the modulating (or information or message) signal +A -A T c t c(t)

10. Four main modulation techniques Changing amplitude (A c ) of carrier according to modulating signal Changing phase (  c ) of carrier according to modulating signal Changing frequency (f c ) of carrier according to modulating signal Combination of ASK and PSK

14. Frequency Shift Keying (FSK) ctd… Information or message or baseband data Carrier wave or carrier Data stream: BFSK waveform (bandpass signal) 0 1 1 0 1 0 0 1

17. Phase Shift Keying (PSK) ctd…  c = 0 rad (=0  )  c =  rad (=180  ) t t c(t) c(t+  ) t t  c = 3  /2 rad (=270  )  c =  /2 rad (=90  ) c(t+ 3  /2) c(t+  /2)

18. Phase Shift Keying (PSK) ctd… Binary PSK (BPSK) represents ones and zeros by shifting the phase by  1 and  2 Binary zero  phase  1 (0 rad or 0  ) Binary one  phase  2 (  rad or 180  ) PSK  phase of carrier is changed according to modulating signal

19. Phase Shift Keying (PSK) ctd… Information or message or baseband data Carrier wave or carrier Data stream: BPSK waveform (bandpass signal) 0 1 1 0 1 0 0 1

20. PSK: Phasor or vector diagrams (constellation diagram)  =0 rad =0  = 2  rad =360   =  /2 rad =90   =  rad =180   =3  /2 rad =270 

21. BPSK: Phasor or vector diagram (constellation diagram) m 1 m 2 Binary: two possible states m 1 and m 2 Euclidean distance: distance between two message points  =0  =  /2  =   =3  /2 Decision region 1 Decision region 2 Decision boundary

22. Quadrature Phase Shift Keying (QPSK) - Phasor or vector diagram  =0  =  /2  =   =3  /2 m 1 m 2 Quadrature: four possible states m 1 , m 2 ,m 3 and m 4 m 4 m 3 Decision region 1 Decision region 2 Decision region 3 Decision region 4 Decision boundary Decision boundary

23. M-ary Phase Shift Keying (MPSK) - Phasor or vector diagram  =0  =  /2  =   =3  /2 m 1 m 3 M-ary: M possible states m 1 , m 2 , m 3 , … m M m 7 m 5 m 8 m 6 m 4 m 2 Signal constellation for 8-PSK Region 1 Region 8 Region 4 Region 2 Region 7 Region 3 Region 5 Region 6

33. This resource was created by the University of Hertfordshire and released as an open educational resource through the Open Engineering Resources project of the HE Academy Engineering Subject Centre. The Open Engineering Resources project was funded by HEFCE and part of the JISC/HE Academy UKOER programme. © University of Hertfordshire 2009 This work is licensed under a Creative Commons Attribution 2.0 License . The name of the University of Hertfordshire, UH and the UH logo are the name and registered marks of the University of Hertfordshire. To the fullest extent permitted by law the University of Hertfordshire reserves all its rights in its name and marks which may not be used except with its written permission. The JISC logo is licensed under the terms of the Creative Commons Attribution-Non-Commercial-No Derivative Works 2.0 UK: England & Wales Licence. All reproductions must comply with the terms of that licence. The HEA logo is owned by the Higher Education Academy Limited may be freely distributed and copied for educational purposes only, provided that appropriate acknowledgement is given to the Higher Education Academy as the copyright holder and original publisher.