Ee1003 Final Report
| A laser communication system for voice transmission | | | 4/18/2011 | EE1003 report Semester 2, 2010/2011 |
Group: 5HUANG YONGCHANG A0073181L
KHO ENG KIEN A0072980Y
HAR KAH HAUR A0072293EDANIEL TAN HOONG XIANG A0074608B | HENG JEYEE A0074494WCHENG SHAU CHUAN A0074530M DINH QUOC CUONG A0074480ECHOU YANG A0072474A |
A laser communication system for voice transmission EE1003 report for group 5
1. Scope
1.1 Background
Information flow has become increasingly rapid with the advent of telecommunication network and the internet. Information need not be passed down through physical means like mail or newspapers. It can be done through SMS (short messaging service), a phone call or even an email. Underlying such great inventions is the use of electronic devices to transmit and receive signals. Due to the demand for faster and larger data flow, complex systems such as Code-Division Multiple Access (CDMA) have been developed.
This project is confined to the fundamental concepts used in digital communication. These key concepts include sampling, quantization and frame synchronization. The circuit designed is meant for one-way dataflow. It supports transmission by one user from any analog input. Hence, it is not necessary to select between multiple analog inputs using the frequency-division multiplexing technique. In transmitting wirelessly, a laser and photodiode are used instead of antennas. This choice is made because it is complex to build a Frequency Shift Keying (FSK) circuit. Without FSK, an antenna would need to be 75km long in order to transmit a wave of 4 kHz.
1.2 Problem Identification
In this project, a laser pointer is used to transmit analog signal wirelessly. In order to realize digital transmission, the analog signal must be converted into digital form using a Pulse Code Modulation (PCM) encoder. Before the signal can be decoded at the receiver end, frame synchronization must be achieved. Hence, a training sequence must be
Group: 5HUANG YONGCHANG A0073181L
KHO ENG KIEN A0072980Y
HAR KAH HAUR A0072293EDANIEL TAN HOONG XIANG A0074608B | HENG JEYEE A0074494WCHENG SHAU CHUAN A0074530M DINH QUOC CUONG A0074480ECHOU YANG A0072474A |
A laser communication system for voice transmission EE1003 report for group 5
1. Scope
1.1 Background
Information flow has become increasingly rapid with the advent of telecommunication network and the internet. Information need not be passed down through physical means like mail or newspapers. It can be done through SMS (short messaging service), a phone call or even an email. Underlying such great inventions is the use of electronic devices to transmit and receive signals. Due to the demand for faster and larger data flow, complex systems such as Code-Division Multiple Access (CDMA) have been developed.
This project is confined to the fundamental concepts used in digital communication. These key concepts include sampling, quantization and frame synchronization. The circuit designed is meant for one-way dataflow. It supports transmission by one user from any analog input. Hence, it is not necessary to select between multiple analog inputs using the frequency-division multiplexing technique. In transmitting wirelessly, a laser and photodiode are used instead of antennas. This choice is made because it is complex to build a Frequency Shift Keying (FSK) circuit. Without FSK, an antenna would need to be 75km long in order to transmit a wave of 4 kHz.
1.2 Problem Identification
In this project, a laser pointer is used to transmit analog signal wirelessly. In order to realize digital transmission, the analog signal must be converted into digital form using a Pulse Code Modulation (PCM) encoder. Before the signal can be decoded at the receiver end, frame synchronization must be achieved. Hence, a training sequence must be
References: Brown, S., & Vranesic, Z. (2009). Fundamentals of digital logic with VHDL design (3rd ed.). McGraw Hill Education. Department of Electrical and Computer Engineering - National University of Singapore. (2011a). D1 Introduction [PDF Document]. Retrieved from IVLE’s EE2020 workbin Department of Electrical and Computer Engineering - National University of Singapore Harold, P.E.S., & Samy, A.M. (2003).Communication systems: analysis and design (International ed.). Pearson Prentice Hall. Kuphaldt, T.R. (2009). Chapter 8: Operational amplifiers. In Lessons in electric circuits (Vol. III: Semiconductors). Retrieved from http://www.allaboutcircuits.com/pdf/SEMI.pdf Soundproofing 101 Team (n.d.) Zhang, J. (2011a). PCM codec [PDF Document]. Retrieved from IVLE’s EE1003 workbin. Zhang, J. (2011b). Digital Phase Lock Loop (DPLL) [PDF Document]. Retrieved from IVLE’s EE1003 workbin Ziemer, R.E., & Tranter, W.H