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The primary objective of this project was to serve as a learning opportunity to "how to do an electronics project". The project used to meet this objective was a software defined receiver using a sound card to turn the analog signals received by the antenna into digital ones that can then be demodulated with a computer. This project required us to use mathematical knowledge, computer fluency, and electronics skills to successfully complete it.
So why design a receiver? A receiver is a practical device that incorporates a large range of electronics concepts relevant to the scope of this class. This design in particular is based off of a superheterodyne receiver. A superheterodyne utilizes the concept of "heterodyning", or the mixing of signals to obtain sum and difference frequencies. This takes place in the mixer (usually a multiplying mixer).
This block diagram was created by Dr. Frohne, but illustrates our design well
Received signals from an antenna can be incredibly weak, thus a receiver must be quite sensitive in order to make it possible for the user to hear such a signal. At the same time, a single signal must be picked out from a crowded spectrum where nearby signals may be many times stronger. Therefore the receiver must be very selective. Both of these requirements can be met by the use of superheterodyne receiver structure. A block diagram of the project is shown below. It essentially is comprised of an antenna, bandpass filter, local oscillator, mixer, amplifier, soundcard, and a computer to manipulate the software. The theory of how each of these components work and how we designed them are documented in their respective pages on this wiki.
- User Manual: Easy to follow instructions on how to use the device once you have the software and hardware set up.
- Build Plan:Bring-up procedure to minimize errors concerned with construction of the board as well as including a parts list.
- Test Procedure: We hope that this test procedure can help you isolate issues and narrow down your search when looking for issues.
- Local Oscillator: Information regarding the design and function. This addresses the crystal, si5351 clock generator, and johnson counter.
- Band pass Filters: The reasoning behind the design choices of the bandpass filters.
- Tayloe Mixer: Description of the tayloe mixer, how it works, and the role it plays in our radio receiver.
- Low Pass Filter Design: The role of the low pass filter and the tools we used to design it.
- Ground Loops: The concept behind ground loops and how to avoid them.
- Software: Description of Quisk and how to get it installed.
- Results: Quantitative and Qualitative data describing the successes of this project and possible future work.
Thanks for taking the time to look at our project! Feel free to reach out to either Josh or myself if you have any questions. Cheers to your next project!
page created by jordyn watkins | greenjacketgirl