Multi-Access Data Network

Participants: 

Brien Range
Dan Townsend
Prince Mingle
Wyatt Borden

Advisor: 
Prof. Chris Rose




Project Description

● Multiple-Access Data Networks allow more than one device to transmit data over one channel
● The goal of this project was to send two streams of data to a single receiver node
● The group fabricated three modems from scratch and designed their own multiplexing scheme to accomplish this task
● Future work would include implementing this system over a power line network and sending useful data

Modem

● Level shifting device implemented to convert between TTL and RS232 voltage levels
● On-Off Keying modulation scheme with 400 kHz carrier used to transmit serial data over the network
● Energy Detection used for demodulation of OOK signal
● Envelope sent through a schmitt trigger for a clean output

Multiplexing

● Each transmitter waits for a timing signal from the receiver
● Once the timing signal is received, transmitters send data during their time slots for a specified number of rounds.
● Once all rounds have passed, the two transmitters wait for the timing signal, starting the process over.