March 2008

Monthly Archive

Thu 27 Mar 2008

Play DIVX, XVID and more on xbox360

Posted by Steve under Technology , xbox360
[2] Comments 

This can be done with a little effort. I will spare the howto as many others have done this. However, this product is so great it is worth the post to help get the word out.

The idea is simple, if your computer can play it, TVersity can transcode it to a format viewable by your 360. It actually streams to the port that windows media center runs on, so your xbox360 thinks TVersity is a pc with media center.

It took me all of 5 minutes to get this running. You can do it to:
1. Download and install TVersity - http://tversity.com/home
2. Add Directories on your PC to your TVersity library. These Directories can contain any media in any format. music, pics, and vid.
3. Open firewall for TVersity port 41952 and Forward port on router if applicable
4. In the Xbox360 Dashboard, under media –> video –> connect to TVersity.
5. Now play quicktime, divx, xvid, avi, ogg, lossless…… on your xbox360 :D

It even adds more features like the ability to connect to youtube and live TV feeds around the world. TVersity is truly a MUST have for any xbox360 owner.

I currently stream DVD quality DIVX rips over a 54mbit 802.11g to my 360. I can scrub movies very fast. I am very impressed.

 

Sat 22 Mar 2008

March Madness - A Binary Bracket

Posted by Steve under Math , Sports
1 Comment 

Like many, I have spent the last two days hitting the refresh button on my Yahoo NCAA Bracket.

I was curious as to how many possible bracket picks there are. Being a computer guy this is a very easy question to answer. A game is binary, you either win, or you loose. There are 63 games played. (32+16+8+4+2+1 or 11111 in binary)

Anyways 2 outcomes for each 63 games is 2^63 possibilities. Thats far, far, far more than what most people would expect.
In computer terms that is over 8 million terabytes of data!

Here is a little binary math:
2^10 = 1024 == 1000 == 1k
2^30 = 1k*1k*1k ==1 gig
2^40 = 1k*1gig == 1 tb
2^50 = 1k * 1tb
2^60 = 1k * 1k * 1tb == 1 million terrabytes
2^3 = 8

8 Million Terabytes!

 

Mon 3 Mar 2008

Fourier Transform of a Damped Sinusoidal Wave

Posted by Steve under Math , Signal Analysis
1 Comment 

Spent some time on the problem for homework in my Communication Theory Course. The problem is a Fourier Transform of a damped sinusoidal wave. I plan on adding Matlab Graphs in a couple days…

Here, g(t) is the signal in the time domain. G(f) is the transform to the frequency domain. Enjoy!

g(t)=e^{-t}sin(2\pi{f_{c}}t)u(t)

G(f)=\int_{\small-\infty}^{\small\infty}e^{-t}sin(2\pi{f_{c}}t)u(t)e^{-j2\pi{f}t}dt

G(f)=\int_{\small0}^{\small\infty}e^{\small-t}\frac{e^{j2\pi{f_{c}}t}-e^{-j2\pi{f_{c}}t}}{2j}e^{-j2\pi{f}t}dt

G(f)=\frac{1}{2j}\int_{\small0}^{\small\infty}e^{j2\pi{f_{c}}t-t-j2\pi{f}t}-e^{-j2\pi{f_{c}}t-t-j2\pi{f}t}dt

G(f)=\frac{1}{2j}\biggl[\frac{e^{-t(-j2\pi{f_{c}}+1+j2\pi{f})}}{-j2\pi{f_{c}}+1+j2\pi{f}}\biggr]_0^{\infty}-\frac{1}{2j}\biggl[\frac{e^{-t(j2\pi{f_{c}}+1+j2\pi{f})}}{j2\pi{f_{c}}+1+j2\pi{f}}\biggr]_0^{\infty}

G(f)=\frac{1}{2j}\biggl[\frac{1}{j2\pi{f_{c}}-1-j2\pi{f}}\biggr]-\frac{1}{2j}\biggl[\frac{1}{-j2\pi{f_{c}}-1-j2\pi{f}}\biggr]

G(f)=\frac{1}{2j}\biggl[\frac{-j2\pi{f_{c}}-1-j2\pi{f}-j2\pi{f_{c}}+1+j2\pi{f}}{(j2\pi{f_{c}}-1-j2\pi{f})(-j2\pi{f_{c}}-1-j2\pi{f})}\biggr]

G(f)=\frac{1}{2j}\biggl[\frac{j4\pi{f_{c}}}{4\pi^2f_{c}^2+4\pi^2f_{c}f+1+j2\pi{f}-4\pi^2f_{c}f+j2\pi{f}-4\pi^2{f}^2}\biggr]

G(f)=\frac{2\pi{f_{c}}}{1+4\pi^2({f_{c}^2}-f^2)+j4\pi{f}}

Graph Damped sin with Frequency of 30Hz
Damped Sinusoidal Wave

Graph of Frequency Response
Damped Sinusoidal Wave Frequency Response