Lab 4-5 ================================================================
This is a two session laboratory.
Simulate and demonstrate 4 ASK, and 2 and 4 PSK, of a random binary message over a band limited noisey channel. Transmit the sine wave as an 8-bit signal using a digital encoding scheme of your choice (simple binary is adequate, but bonus points for understanding and describing it as PCM, extra bonus points for converting to gray coding and explaining the advantage of doing so).
An example Matlab script is given to you to get you started. Play with the parameters in it, and get a handle on how it works. The bulk of your time will be dedicated to working out how to implement the PSK.
(Bonus grades will be given for shaping the pulses with either a raised cosine filter or a Gaussian filter to minimise ISI and maximise data transmission speed.)
Perform coherrent demodulation and recover the message. You may assume the receiver LO is phase locked with the transmitter.
Examine the signals in time and in frequency. Do they match with the theory?
Project ================================================================
You will need to work in pairs for this project. There will be one lab session dedicated to this, but it is anticipated that you will need to continue on to complete it.
Design a 2 and 4 DQPSK encoding/decoding system from scratch in Matlab.
Test the system over a simulated band limited noisey channel with a phase shift due to travel
distance.
Adapt and use this above code to ensure that the data transmission and reception are both operating correctly.
A useful trick is the hilbert function (you are not obligated to use it). The Hilbert transform transform a signal form real to complex. Phase at each point in the sampled and Hilbert transformed signal is found by the angle function. But, phase wrapping will cause problems: how to we address this?
Write your report on the design and how you tested it.
Reviews
There are no reviews yet.