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Wednesday, June 8, 2011

Change of directions

I finished my electrical engineering in S.V.University and working in HCL as embedded systems hardware engineer. Initially i have started this blog to share the ideas on the technical stuff either hardware or software, as my thoughts and ideas are taking me to financial world so often, seems to be there is a change of direction in the blogging and and my thoughts, so i want to share my thoughts, ideas and the books i read in this blog.

I want to become independent investor, so i am laying the ground work to get there without going Bschool. I have started reading few books on the investment that i am going to share now.

1. Common stocks and uncommon profits by Phil A.Fisher
2. Financial Intelligence by Karen Berman, Joe Knight, John case
3. Warren Buffet and interpretation of financial statement by Mary Buffet and David Clark
4. One Up On Wallstreet by Peter lynch

1. Intelligent investor by Benjamin graham
2. Security analysis by Benjamin Graham and David Dodd
I will share the other books which are related to personal improvement and business in the next blog and also my own review of the books i read.

If anyone has similar ideas and sailing in the same boat, pleas join me and we can share the topics and discussions.

thanks
Uma

Thursday, May 15, 2008

Signal Integrity

What is Signal integrity?

This is one of the emerging fields in the electronic industry. As quoted by Dr.Howard Johnson "Signal integrity is a field of study half way between digital design and analog circuit theory."

Signal Integrity is an engineering pratice
-that ensures all signals transmitted are recieved correctly,
-that ensures signals don't intefere with another in a way to degrade the reception,
-that ensures signal doesnot damage any device,
-that ensures signal don't pollute the electrmoagnetic spectrum.

what actual it means, at low frequencies, an ordinary wire will effectively short the two circuits. this is not the case at high frequencies. At high frequencies, only a wide flat object can short the two circuits. The same wire which is so effective at low frequencies has too much inductance to function as a short at high-frequencies. we might use it as a high frequency inductor but not as a high frequency short circuit.

Is this common occurence? Do circuit elements that work in one frequency range normally not work in different frequency range? Are electrical parameters are that much frequency sensitive?
Yes.

Due to the high speed, boards are experiencing the problems.

The Four High speed SI Problems:

1. Signal Quality
2. Cross Talk
3. Rail Collapse
4. EMI
For deeper discussion on SI problems, please wait for the next article
For the Deeper understanding about high speed digital design and circuits please refer the below references.

References:

1. High Speed Digital Design By Dr.Howard Johnson, Martin Graham.
2. Signal Integrity - Simplified By Eric Bogatin
3. High Speed Digital System Design - A handbook of interconnect Theory and Design Practices By Stephen H.Hall

Saturday, October 20, 2007

Changing Boot options in GRUB

GRUB (GRand Unified Boot loader) is Multiboot Boot Loader. Briefly, boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to the operating system kernel software.

GRUB is the bootloader on my system where it has WinXP and Fedora 7.
First I installed WinXP and then Fedora 7(F7). As I chose default options in installing F7, the default boot option was set to F7. Now this post gives the way to change the boot options in GRUB, so that the default is to WinXP:

First boot to F7 and then open a terminal and login into root using su -, then
cd /boot/grub
cat grub.conf -- If menu.lst is not there, then directly use grub.conf

which displays the following

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You do not have a /boot partition. This means that
# all kernel and initrd paths are relative to /, eg.
# root (hd0,6)
# kernel /boot/vmlinuz-version ro root=/dev/sda7
# initrd /boot/initrd-version.img
#boot=/dev/sda
default=0
timeout=5

splashimage=(hd0,6)/boot/grub/splash.xpm.gz ?
title Fedora Core (2.6.21-1.3194.fc7)
root (hd0,6)
kernel /boot/vmlinuz-2.6.21-1.3194.fc7 ro root=LABEL=/ rhgb quiet
initrd /boot/initrd-2.6.21-1.3194.fc7.img
title Other
rootnoverify (hd0,0)

title 0 is Fedora Core and title 1 is Other. Other corresponds to WinXP.
but the default = 0 specifies title 0 is selected, so to change the default OS to be booted, I need to change this default.

So to boot into WinXP by default, change to default = 1 (where title 1 corresponds to Other means WinXP)

Timeout specifies the time the system waits, in which if we didn't press any key, the default OS will be booted. In mean time if we press any key then we will get the Boot Menu to chose the OS to be loaded.Here Timeout = 5 so there will be 5 seconds time for me to get booted into default OS.

Friday, October 19, 2007

Want YOUROWN Linux Distro -- A Good Learning Exercise

Sounding like conquering another world, an impossible thing....Absolutely wrong if you think so. For Novice Linux users like me probably it must be daunting task. But there is a solution for that too. Linux From Scratch(LFS). Of course its not at all a program/course which is meant to create the OS like the way OS developed from decades...Again Its not just putting the DVD of a magazine and just installing some XYZ default packages which u even dont know ...Then what exactly this LFS.
LFS gives u the feasibility of designing your own os. I mean the packages,programs, etc u need for ur environment. of course u can change and tweak the source to ur needs.
Simply LFS is to use the existing host Linux system's development tools to develop ur own distro using the source tar balls of different pacakges and programs that are downloaded or created by our own.
Also, for the novice users like me, it will give good understanding of how a Linux system works, how it ticks with the hardware..A good learning exercise.

After getting good idea of ur environment and then the applications u need just try to build ur own Linux distro using the existing Linux Host system's development tools. For getting help on this, just try to search LFS in Google, The Great. And also plz visit http://www.linuxfromscratch.org/.

Friday, June 15, 2007

Design a SEPIC Converter

This article tells about what is a sepic converter, how to design it. A SEPIC (single ended primary inductor converter) is a non-isolated DC-DC converter which allows the output voltage to be greater than, less than, or equal to the input voltage,which seems to be similar like buck-Boost converter type, but SEPIC gives positive voltage at the output,whereas a buck boost converter gives negative voltage at the output.In buck-boost configaration output current is continuous, input current is discontinuous, whereas in SEPIC both output and input currents are continuous. Lets find out more in the following links.

for circuit operation:
http://en.wikipedia.org/wiki/SEPIC_converter

for designing sepic converter:
http://www.national.com/an/AN/AN-1484.pdf

Tuesday, June 5, 2007

World of LaTeX

"LaTeX?? What the heck?" This is what many people say when they hear the word "LaTeX". If you are one among them, then go on and read this post.

1. Did you ever use editors like Word, OpenOffice etc for producing your project reports, paper presentations, or journal articles? If so, after typing a few hundred pages, what happened when you inserted an image file in between your paragraphs? My experience in such situations is worst. My friends and I faced this problem when we prepared our undergraduate project reports. All our previous page settings were disturbed when we tried to insert or resize a picture. Once again, we set out to format the entire document.

2. Did you insert some serious Mathematical equations or formulae in your documents? It is a pain in your ass if you do that in normal editors like Word, despite its Equation Editor.

3. How about the quality of your content? I concentrated more on document layout and its appearance. This affected the quality of my content.

One of the solutions to these problems is LaTeX. Simply put, LaTeX is an open source typesetting system. It is especially useful for developing professional and well-structured documents. The main advantage of using LaTeX is that, it allows you to concentrate on your content and forget about the layout; because LaTeX takes care of the actual typesetting (font styles, alignment etc), structuring of your content and page formatting. Though it is a little bit difficult to learn, LaTeX produces high-quality technical and scientific documents easily. Once you learn how to use LaTeX, it makes your life easy.

So much to say about LaTeX. Let us see this in action. Don't expect to learn LaTeX in one day. It needs a lot of patience to master the basics. Go through the links provided at the end of this post to learn more about LaTeX. By the way, don't panic by looking at the code. It is provided to show how easy it is to produce quality reports.

Installation: To install LaTeX under Windows, follow this procedure -- Download and install basic MikTeX. Install a LaTeX editor like TeXnicCenter. Copy and paste the code given below in an empty document inside TeXnicCenter. Save the file as "demo.tex", without quotes.

%--------------------------------------------
% Example of LaTeX
% File: demo.tex
% Author: Trisul Kanipakam
% Date: Tuesday, June 05, 2007.

\documentclass[11pt]{article}
\usepackage{palatino,url}
\usepackage{amsmath}

\begin{document}

\author{Trisul Kanipakam}
\title{\LaTeX\ example}
\date{\today}
\maketitle

\section*{Hello World!}
This is a sample \LaTeX\ document. We can generate an article like this with a default font size of 11pt, using \textit{Palatino} font. Note that, i don't have to format section headings, justification, numbering of sections and pages etc. We can easily generate tables and center them,\\

\begin{center}
\begin{tabular}{cc}
\hline
Sno & Data \\
\hline
1 & 1000 \\
2 & 2000 \\
\hline
\end{tabular}
\end{center}

Listings can be generated as shown below:
\begin{itemize}
\item \emph{$e=m*c^2$},\quad $\sqrt{4}=2$, \quad $\int_0^2 \zeta^{2}(x) \, dx$, \quad $\frac{dy}{dx} \rightarrow 0$, \quad $\alpha \neq 0$, \quad $F(x_{1}, x_{2}, \ldots , x_{n}),$ \quad $(u, \infty)$, \quad $\lim_{x \to \infty} f(x)$.
\item Matrices and Limits
$\lim_{x \to a} \frac{f(x) - f(a)}{x - a}, \quad \begin{pmatrix} a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp; b & c & d\\ x & y & z & w \end{pmatrix}$
\end{itemize}

\begin{center}
\textit{Have a nice time learning \LaTeX\ !}
\end{center}

\end{document}

% End of document.
%-----------------------------------

If everything goes well, you should see something like this.

Now Build the current file in TeXnicCenter to produce a nice looking pdf file as shown below.

Thats it. Forget the WYSIWYG editors and enter the world of LaTeX.

1. Getting to Grips with LaTeX

2. LaTeX isn't for everyone but it could be for you

3. The beauty of LaTeX

4. The not so short introduction to LaTeX

5. Getting started with LaTeX

Hey i ran out of space. Google "latex tutorials" for more links.

Friday, June 1, 2007

Buck-Converter Design Demystified

Hi,

This is one of the most simplest and useful articles, the author explains the buck converter