Saturday, November 14, 2009

Signal Processing

Well, it's been a while since the last update.

I've finally managed to implement digital signal processing in the L2Dopplar project. I have only implemented one digital filter as of right now - the sliding window averaging filter. It is possible however to implement more complex signal processing with the current setup. We have enough information available to any particular digital filter to do FFT transformations, as well as look at the signal in the time domain.

Sean is currently working on a Qt front end for the program. Hopefully we'll have this complete before too long.

As far as performing an MCG with this setup is concerned, the capacity to perform that specific task is simply not there. We can get good information about large differences in ping times. The current implementation would be suitable for car crash detection. Unfortunately, the current setup does not have enough resolution to pick up a heart beat. It is now out of the scope of this semester project to implement an MCG using this system.

We propose a new "hardware backpack" for cellular phones (specifically the android) which has an FPGA with a custom antenna to pick up detailed information regarding the incoming signal from the ping. We can use a mobile phone to send a ping to its backpack which is isolated from the phone via some sort of Faraday cage - and have the backpack do detailed dopplar level calculations. With a system like this, we could potentially sense a heartbeat behind a wall. This will be a good project for second semester when funding goes back up.

Anyway, I've uploaded the new signal processing core to SVN. Check it out if you want. I haven't tested it very thoroughly, but it might just work!