Dypsa Algorithm

Dypsa Algorithm is a common algorithm used in speech signal processing using Matlab. Its part of the Voicebox toolbox that’s available online for free. You can download it here!. Download the Zip file or click here to download the zip file anyway. The Zip file contains a whole lot of other Algorithms along with dypsa. Install the toolbox by setting the path to it or if you don’t know how to do that just paste all the codes or dypsa.m file alone(if you are going to use dypsa alone) in the current working directory. That should do the trick

What Dypsa does.

Basically what Dypsa does is, It extracts the Glottal Closure Instants(GCI) and the Glottal Opening Instants(GOI) form the speech signal that you provide it. So you would get two matrices one corresponding to the GCI and one corresponding to the GOI if you run a wav file through dypsa algorithm. These matrices will contain the locations, or the sample numbers, of the places of the glottal closure and opening instants. I will provide you a small piece of code incase you need an example of how to use it.

Glottal Closure and Opening Instants.

So what are these instants. Every time you produce a sound (a voiced sound), your glottis flaps. There is an instant where it is closed and there is an instant where it is open. If you take into account one of these instants, either the closure or the opening instants, you will get an idea of the pitch of the speaker. The distance between two successive samples is the Pitch Period, and the from this you can find out the pitch contour (which I don’t want to confuse you with, here).

How these instants can be related to pitch?, is a good question, which again I do not want to post here in the same blog.


Although Dypsa algorithm can find out the GCI and the GOI of the speech signal. It also gives us some values at the unvoiced portion of the speech too. This particular point about dypsa should be noted. Because for a lot of applications it would be a negative aspect.


clear all;
close all;
[input,Fs] = wavread(‘tapestry’);
[gci, goi] = dypsa(input, Fs);
impulseC(gci) = 1;
impulseO(goi)= 1;
subplot(3,1,1),plot(input((6500:8500),1)),title(‘Voiced Segment of thee Input signal’),axis(‘tight’);
subplot(3,1,2),plot(impulseCT((6500:8500),1),’r’),title(‘Impulse Signal, based on GCI’),axis(‘tight’);
subplot(3,1,3),plot(impulseOT((6500:8500),1),’b’),title(‘Impulse Signal, based on GOI’),axis(‘tight’);

What I’ve done here is that, I’ve read the wave file and stored it in input and ive given it to dypsa which will give me the gci and goi in line 4. Since dypsa only gives the locations of the gci and goi I’ve converted it to impulses so that you can see it when you plot it.

In order to read a wavefile, put the wave file in your working directory.

Doubts are welcome.

Thanks for reading.



Using Laptop as a Router, Windows 7, USB Modem or LAN Connection Required

Click the link below to know how to use your laptop as a router. This is a great website where you can learn a lot of cool stuff.

But before you click it. Do not close this page because you would most probably come back because there is one just tiny detail missing.

Click here!

So I’ve assumed that you’ve read the whole thing and if you are back here its probably because you want to know what to do with this particular thing… What do you click.?… Click on “Wireless Network Connection” and click ok. That should do it. You are clicking on Wireless network connection because that’s what you are going to use to create you home network with the devices you want to share your internet connection with.


So basically what you do is. Create a network (ad-hoc) with your devices and then use your laptop as a gateway to the internet using the 3G modem or the LAN connection. If you get it. Its good. If not. Have fun using your new wifi connection without worrying about all this.

Reopen the properties dialog box and click on the sharing tab and you should have this.



This could be very useful for all those iPod users out there like me. You need an internet connection badly. You don’t have a router with you. You could use your phone as a wifi hotspot. That would be a good option. But how many times would you recharge your phone in a day. The battery dries out so quickly. If you want to know how to use your Nokia phone as a hotspot though, Check out this blog post!.

Another easy way is to get one of those small pocket routers. This one from TP LINK was impressive and cheap. It costs 1900 INR. 1850 INR in Flipkart as of today. That would be about 30 to 35 USD I guess. Try it out if you have the cash and if you think you shouldn’t put your laptop through too much work, if you think this is too much work. *wink


Internet Explorer impressed me with this one

Well the whole world is at it. “Internet Explorer sucks”. “Internet explorer is only good enough to download firefox or chrome”. Bla bla. The list goes on. But then sometimes internet explorer impresses me. If you have used firefox or opera or chrome you would know that when the browser crashes due to a particular webpage, it restarts. But what it does is, gets your session back. It reloads all the pages that you were using. Although this is a nifty feature. Internet explorer just went one step ahead for a change and it really impressed me.

Whenever a page makes your browser to crash, IE just closes the tab and reloads it. Not disturbing any of the other tabs that you have kept opened. In other words, You will not have the experience of a browser crashing even if it does. Because it just take two seconds to clear it off. You are prompted that the particular webpage made IE to crash, and that the page will reload. You click ok and that’s it.!.

Believe it or not. I prefer using IE in college and Firefox at home. IE gives me some advantages over other browsers when I browse through my institution’s proxy server. I don’t know how, but it does. So I love it.


JoikuSpot, First Review

In my previous post, I said I would tell you how my experience with Joikuspot goes.

What is Joikuspot:

Joikuspot is an app you can install in your nokia phone running on symbian. It can turn your phone into a wifi hotspot so that you can use your phones 2G or 3G connection on other devices that come with only WiFi like an iPod. There are two versions. A free version and a premium version. The premium version cost me 35/- INR. That’s less than a dollar. Go to the Nokia Ovi Store and check it out.

Review, First Looks:

I’ve been using this software for less than two days, so I’m writing this post under the assumption that it would work the same way in the future too. If there are any modifications to what ive said below. I would write another blog and put a link to that in this one.

Although its performance was clean with no bugs or glitches it did suck a lot of battery out of my phone. If you are planning to use it for a long time you might want to carry your phones charger with you all the time. Yesterday, I recharged my phone thrice. I usually do it once everyday. I did not even use the software the whole time. I used it occasionally. With a total time span of maybe three to four hours.


But I do not blame the software though. I don’t think you can possibly build a better one, (As far as I know) because, it uses both your GPRS and your Wireless adapter simultaneously. It pulls data from web servers using GPRS and it has to use its WLAN card to route it to other devices. Using both simultaneously will surely pull a lot of power.

I suggest you use this when you ..
1. are really bored outside and you don’t really care about battery life.
2. are desperate to use your iPod or any other device that has only wifi but no 3g. Desperate to harvest that crop you planted today morning on farmville maybe? Winking smile
3. have your phone’s charger with you.

In any other case, It would be a bad choice.

Thanks for reading..


Connect iPod to the Internet with your own WiFi Source

Using an iPod touch outside, on the streets, or in places without a WiFi source has always been a problem for many people. You are left stranded. Frankly the ipod touch is just a paper weight when it does not have internet connection. How ever there are three ways to go around this problem.
1. Connect your laptop to the Internet using an USB modem and make it act as an hotspot.
2. Buy one of those wireless routers that can work from a 3G SIM card. They are small and you can carry it around where ever you want. It would probably fit in your pocket or put it in your backpack. They work with battery power. That can last a long time.
3. The third solution is an economical one, but it works at the expense of your phones battery life. The third solution is to just turn your phone into a wifi hotspot. Android comes with that ability so you don’t have to worry about it. You just have to find it in your phone and switch it on. Nokia users however have a problem. They have to install an app.
I use JoikuSpot in my phone. There are two versions. One is a free version and the other is a premium version. It cost me 35rs for the premium version. That is not even a dollar. Before you buy the premium though. Try out the free version to see if you get what you need. He patient if you are stuck anywhere. 🙂 . I’m sure it’ll work fine.
I’m having a Nokia 5530 running on s60 operating system by the way. I used JoikuSpot and I’m using the wifi from my Nokia on my iPod to type this blog right now. I’m not sure about how much battery it sucks. I’d have to check that out. Will make another post with those details.
Thanks for reading… 🙂