Cairo University and Analog Devices Cooperation in the Field of Digital Signal Processing and Embedded Systems

Since Fall 2002, the department of Electronics and Communications Engineering/Cairo University has been in cooperation with Analog Devices INC. Analog Device donated five EZ-LITE 21061 DSP kits, ten Blackfin BF531 kits, and Visual DSP software. The following is a summary of the projects done using these kits and the Visual DSP software. For more information, contact Dr. Khaled Fouad Elsayed (Khaled AT IEEE.ORG).

B.Sc. Senior Projects

1. Part 1: Internet Protocol (IP): specifies the format of packets and the addressing scheme. It allows you to address a package of information and drop it in the system, but there’s no direct link between sender and the recipient.
2. Part 2: Television (TV): We all know TV, but here we are referring to the services that are offered for the TV, like linear and on demand programming.
   

The project objective is implementing IPTV viewing device on embedded Linux system. The output of the project was an MPEG2 Player on embedded Linux system based on Blackfin architecture on a ADSP-BF533 EZKIT LITE. The following figure shows the mpeg2 player block diagram.

A summary of the project is available here.

This project discuss the implementation of OFDM system over power lines as a communication technique capable of removing the effects of multi path fading

The main idea of the project is to build two separate power line systems, one utilizing the ordinary FSK modulator with a simple coupling equipment,  the second is OFDM system over power  lines and compare the performance for both of the two cases.

A summary of the project is available here.

Software Radio Transceiver, in its widest meaning, defines a general TX/RX architecture that can be completely reconfigured, directly operating on an RF digitized information stream. Analog processing is limited at the RF front-end, where a pass-band image-rejection filter selects a large spectrum portion containing the desired services.

After a LNA, an ADC converts the signal with the precision required by the system specifications. The digital RF stream is then fed to the Digital processors (RSP, DSP) that:

• Centers the received signal spectrum to the band of services of interest.

• Lowers the sampling frequency of the digital stream down to the minimum rate required by the standard specifications.

• Operates the necessary filtering in order to reject the unwanted adjacent  signals.

• Demodulates the symbol flow and supplies the information bit-stream, for subsequent processing, to higher layers hardware and software.

In our project we designed and constructed an SDR for analog FM reception using three evaluation boards and a DSP kit from Analog Devices as illustrated in the following diagram. The A/D sub-samples the RF signal in the third Nyquist zone (88 MHz to 108 MHz), The RSP down-converts the selected channel to zero-IF. The software on the DSP kit acquires the complex low-pass signal through its serial port and DMA channel, demodulates it and outputs the resulting audio to the speaker.

The project target is transmitting a digital data stream between two DSP KITS using OFDM communication system. Each kit will be connected to a PC via serial port, one of them will work as a transmitter and the other will work as a receiver. After completing the system design on the Visual DSP development environment on a PC, the program code is downloaded on the kit via serial port. In the running mode the kit that acts as a transmitter will take a digital data from its pc through serial port then it generates an OFDM packet and transmits this packet in analog form via sound port. The kit that acts as a receiver will receive the transmitted packet from the sound port then does the reverse action of the transmitter, finally it sends the digital information received to the PC via serial port. The following figure provides a block diagram of the actual system.

 

Due to the current trend of personal wireless communication, there are growing needs for both higher bit rate data transmission and more efficient multiple access techniques.

To fulfill these demands these, a new scheme named orthogonal frequency and code division multiplexing (OFCDM ) that combines orthogonal frequency  division multiplexing (OFDM) and variable spreading factor code division multiple access (VSF-CDMA) was proposed. This scheme is capable of providing but rates above 100 Mbps using an approximate 50-100 MHZ bandwidth. So, it can be a solution for the future increase in the amount of data traffic expected in 4G systems.

This project is an attempt to realize an OFCDM transceiver using the Analog Devices EZ-LITE 21061 DSP KIT. The design was verified on MATLAB and then each block was coded and tested on the EZ-LITE 21061 DSP KIT. The following figures illustrate the transmitter and receiver blocks. The project only implemented a constant spreading factor for CDMA.