Fix: Unable to open some websites on ADSL internet connection

Unable to open some websites on your ADSL internet connection? I came across this problem when I couldn't open irctc.co.in on my BSNL internet connection. This post explains why some websites fail to load on ADSL connections and how to work around the problem.

Syntax highlighting code in Blogger

So far, I've been using the Courier monospace font to show code in my posts on Blogger. Jekyll has better support for syntax highlighting and a static site with Github pages is the "in thing" these days. Let's see how well Prettify works with Blogger for syntax highlighting.

On Signal to Noise Ratio (SNR)

A large part of circuit design is about making trade-offs between speed, cost, power consumption and so on while meeting some design specification that can often be traced to Signal to Noise ratio (SNR). Yet, possibly for pedagogical reasons, SNR is often under-emphasized in undergraduate classes. Remember those amplifiers you heard/read about years ago ? This post will demonstrate a canonical application of amplifiers and show you how to measure SNR of a signal captured from an Arduino.

Interpreting the fourier transform

A friend of mine, who is a designer, asked me how the Fourier transform is interpreted. I'm turning my answer into a blog post in the hope that this might help non EE/math people in dealing with real-world signals.

NTSC demystified - Cheats - Part 6

Throughout this series of articles we've seen a number of "cheats" or non-standard signals which simplify NTSC signal generation. This post summarizes them.

NTSC demystified - Implementation - Part 5

Now that we understand how NTSC color coding works and the math behind it, it's time to think of ways to implement color coding. Knowing the math helps because that knowledge equips us to abuse the system and implement color using simpler/cheaper hardware.

NTSC demystified - Math - Part 4

This post targets largely electrical engineers and involves a bit of math and basics of analog communication. A more formal treatment of the NTSC color signal along with results, which will assist digital NTSC color signal generation is presented.

NTSC demystified - Nuances and Numbers - Part 3

Ever since I understood how NTSC color worked, I've had a nagging question. How does the TV separate color info (color sub-carier) from the luminance information. If the same color was maintained all throughout the line, then the color carrier can be removed away by narrow band-reject filtering. But when the color changes (phase changes) , then how does the TV distinguish color from luminance which is also possibly changing ?

DSP Library for LPC17xx

NXP has most kindly provided a free assembly coded DSP library for its users. I needed to extract the fundamental frequency of an audio signal and with this library, the job got over in 5 minutes.

NTSC demystified - Color Encoding - Part 2

NTSC composite video is a compatible standard. This means that video signal works with older B&W TV Sets as well. So, we're looking to understand how color information is added to the B&W NTSC signal in such a way that Color TV sets can decode the color information while older B&W TV sets ignore the color information. Developing such a signal must have been a formidable task indeed !

NTSC demystified - B&W Video and Sync - Part 1

NTSC progressive scanning mode and simpler sync methods are not well documented and this issue is addressed here. Producing video signals by going to lowest hardware level is fun and satisfying. With the number of very capable digital controllers available to hobbyists today, it has become possible to generate analog video signals entirely in software. With the techniques and sync patterns presented here, generating "software video" becomes a much easier task.

LPC17xx Virtual COM port - A USB CDC Class device library

With physical COM ports non-existent in laptops and fast disappearing on desktops, its a matter of immense convenience to embedded programmers if a chip has the USB interface.

Code Sourcery g++ Lite and Programmer's Notepad for LPC1768 development

Eclipse is a fantastic IDE but some may prefer the light weight Programmer's Notepad. This post will show you how easy development for LPC1768 on a Windows box using CodeSourcery g++ Lite and Programmers notepad is.

Interrupts, Software Interrupts and Interrupt Priority in LPC1768

The cortex-m3 core which the LPC1768 uses has an extremely flexible interrupt controller called the NVIC (Nested Vectored Interrupt Controller). The NVIC has several distinguishing features.

Using the PLL on LPC17xx

The Phase Locked Loop is a peripheral on the LPC17xx that can be used to obtain various frequencies from the frequency sources available. It can multiply and divide the reference frequency to obtain a wide range of CPU frequencies. This tutorial describes how PLL0 can be used.

Hello Word ( LED blinker ) on LPC1768 explained. GPIO tutorial

Traditionally, blinking an LED has been the first program written for almost any embedded system and LPC1768 is no exception. Here's a detailed description of all the software tools needed to get started. The LPC1768H schematic is available in the NGX website. The schematics show that TEST_LED is connected to P1.29. Now, for the register description, we'll need the LPC1768 manual.

Hello World from LPC1768

Finally, the blueboard LPC1768-H arrived. Have a look.

http://shop.ngxtechnologies.com/product_info.php?cPath=21&products_id=65

Unfortunately, it did not have accessories like JTAG cable or mini-USB cable. So, a quick visit to the local electronics store was needed. Once the mini-USB cable was plugged into the blueboard, the LED started blinking. Apparently NGX had pre-loaded the board with a test program. Now I had to say "hello world" through the board.