First of all, our apologies for not keeping this page up to date throughout the spring semester. The UWB team was busy with this project though, that's for sure! It is not feasible to list every accomplishment made since the last update, but to summarize:
The transmitter and receiver baseband Simulink models were completed and simulate correctly
The transmitter model was successfully uploaded to the DSP and worked correctly
Frame and Symbol synchronization were successfully added to the receiver model
The receiver model was too complex for Code Composer Studio, and was not implemented in hardware
The RF subsystem was thoroughly tested and it works correctly
In the next few days, the entire final report will be uploaded which contains everything pertinent to this project as far as the research, implementation, and final results is concerned. Also, take a look at our final oral presentation in the deliverables section.
The UWB team feels they were successful in increasing awareness at Bradley University and in developing a scaled-down proof of concept. Much more work lies ahead for future projects to continue advancing forward.
February 27, 2007
The UWB design team has been forging along at a steady rate during the past week and a half. During today's lab period, both Nathan and Jarrod made progress on the Simulink model and RF hardware, respectively. Nathan was able to tackle the sampling rate issues, and solve a few other errors that we were having. He also was successful in adding a preamble to the beginning of the transmission. This preamble will allow the receiver to take the transmitted data and decipher when the OFDM frame begins and ends so the transmitted data can be properly un-modulated.
Meanwhile, Jarrod went through the datasheets for the new RF hardware that was received from Hittite - the local oscillator and the quadrature modulator. The demodulator has not arrived yet. Jarrod tested the oscillator's performance using the spectrum analyzer in the RF communications lab. The output frequency versus tuning voltage correlated nicely with the data sheets. The output power didn't match exactly, but the range of values will be sufficient for the operation of the modulator.
Some issues to solve in the coming weeks includes finding cables to interconnect all of the hardware (including properly connecting 3.5 mm audio jacks to SMA connectors), testing the quadrature modulator, solving the errors occurring in Simulink concerning rate conversion due to DSP implementation, implementing and testing OFDM frame synchronization.
February 18, 2007
The past two lab periods were spent working on the Simulink model. Specifically, work was done to add the down conversion blocks to the model for the receiver. Lots of debugging was done as well. The sampling rates of the different subsystems had to be changed in order to get the simulation to run. However, the receiver is not recognizing any incoming signals. The next step is to implement synchronization between the transmitter and receiver.
Also, the DSP development kits mentioned last week have arrived, along with the Hittite oscillator and modulator. The version of Simulink that is being used supports the 6416 DSPs - including the on-board A/D and D/A converters. A new version of code-composer studio will need to be installed, but this came with the kits. In the coming weeks, work will be divided up between working on the model, and getting the hardware to communicate with the computer.
February 5, 2007
Several things have happened since last week's update. Two DSP boards have been ordered from Texas Instruments. The boards are TI's TMS320C6416 Starter Kits. These feature one of the fastest DSP chips available (1 GHz). The starter kit come with USB connections to computers. These connections in conjunction with Code Composer Studio will allow the boards to be loaded with the UWB model created in Simulink.
During the last lab period, the UWB design team spent the day researching hardware for the project. Specifically, Nathan researched expansion boards for the TI DSP kits. These expansion boards would allow an external analog to digital and digital to analog converters to be added for faster speed sampling. Jarrod also researched this possibility, and also finalized the RF hardware needed. Three components were ordered from Hittite Microwave Corporation. These devices include a direct-quadrature modulator, direct-quadrature de-modulator, and a local oscillator. These will all be printed circuit boards for easy connection with standard SMA connectors. To see how these will be used, please refer to our project proposal.
Finally, we have relaxed the requirements and scope of the project. Due to time and equipment constraints, it was realized that getting a miniature UWB system to work is not feasible. Therefore, the main goal of the project from this point forward will be to get a working OFDM communication system (including the RF transmission) with UWB in mind. This would be the first time any senior EE capstone project has completed a physical wireless communication system at Bradley. Since OFDM is the heart of UWB, this project will be a stepping stone for future UWB research at Bradley.
January 25, 2007
After returning from a long break, the team is getting back on track. The overall goal for the next few weeks is to start determining the hardware needed for this project. After the hardware is ordered more time can be spent working on the various other tasked outlined in the schedule. Jarrod is currently working on research concerning the RF hardware. Specifically, he has narrowed the choice of direct quadrature modulators down to two. Also, he has researched a frequency synthesizer that the department has, to see if it can be used for a local oscillator signal. Meanwhile, Nate has been researching some DAC and ADC as well as some Matlab research to continue moving forward with the UWB Simulink Model.
Collectively the team has also been researching development platforms for the baseband processing. The choice for a development board has been narrowed down. Texas Instruments produces DSP starter kits that are ideal for this project as they will allow at first a proof of concept. From there extra boards might be needed to provide the team with adequate DAC speeds as time permits.
December 5, 2006
Today Jarrod and Nathan finished the oral presentation for the project proposal, and then gave the presentation to the faculty advisors and Design Review Teams (DRTs).
