Friday, November 16, 2007

Crunch Time!!!

I've noticed a rather alarming trend in my scholastic life. Crunch time (invariable related to writing assignments) leads to great epiphanies in visionary concepts. Unfortunately for me, the concepts are far afield from what I'm supposed to be studying.

This week crunch time has hit in a big way. My Senior Paper is many month behind schedule, and is going to be due very soon. Consequently, I'm experiencing amazing visions of how currently available technology has the potential to generate a massive paradigm shift.

In past semesters, I've grasped the concepts of automated (computer assisted) legal research, global news reporting that's customizable for your particular bias, and something vaguely internet related. This time around, though, it's a bit more disruptive:

Software Defined Radio

I've been reading bits and peices about SDR for a few years, but never really undrstood it - the radio spectrum is completely analog, and methods of tuning (that I could understand) require an analog adjustment to a resonance cycle. I didn't understand how you could replace the analog method for tuning to a particular frequency until I came across the GNU Radio Project -

A "conventional" radio tuner works by taking the electrical current induced in an antenna and selectively filtering out that particular frequency, and amplifying it. The amplified signal is then fed into a signal processor. For AM/FM radio, this converts the analog signal to sound, for TV it converts the analog signal to a CRT scanning signal, for HDTV it processes the digital signal as an MPEG stream.

An SDR does the same thing. Intead of selectively filtering out right frequency via an analog amplifier, it converts the entire spectrum to a digital stream with a (relatively) basic Analog-to-Digital converter, then separates out the desired analog frequency from the digital stream.

There's a couple of pretty heady implications with this. First of all, because the entire spectrum has already been digitized, multiple analog signals can be separated simultaneously with the same set of hardware (Just like TiVo!). Secondly (this is where it gets really cool), since the digital stream covers the entire spectrum, you could theoretically use one radio reciever to access any radio signal. With one device, you could recieve and transmit AM, FM, Shortwave, Ham, TV, HDTV, Satellite TV/Radio, Walkie Talkies, Cell phone, cordless phone, Emergency Services, Police/Fire bands, GPS, and wifi. And garage door openers, car remotes, and that wireless thermometer thingamabob.

With one unit, you could recieve and transmit on multiple channels. Simultaneously. In any portion of the spectrum. This is NCC 1701-D deflector dish type stuff, in real life.

I'm picturing a universal communications transceiver card that I could put in my laptop to get access 802.11a/b/g wireless networks, watch TV, place and recieve phone calls, and get GPS info. When a new wireless standard comes out (WiMAX?), I can already access it without needing any new hardware - all I need to do is get the frequency/format data (publically available) and plug it into the SDR, and I'm connected. Without even missing a commercial break.

Oh, did I mention that the whole shebang, start to finish, from the software source code to the hardware schematics to the PCB layouts, are available for free under an open-source license?

Aaaaaand.... back to the crunch.