Electronics FAQ

Operating System: Windows 7 Ultimate 64 bit Download VirtualBox (filename: VirtualBox-4.0.0-69151-Win.exe) from http://www.virtualbox.org/wiki/Downloads Download a ISO image of Android-x86 built for installation on a virtual machine (filename: froyo-vm-20100812) from http://www.android-x86.org/download   Install Virtualbox. Download "VM VirtualBox Extension Pack" (filename:Oracle_VM_VirtualBox_Extension_Pack-4.0.0-69151.vbox-extpack) from http://www.virtualbox.org/wiki/Downloads Install "VM VirtualBox Extension Pack" by double clicking on the file. Start VirtualBox Create a new Virtual Machine named "Android-x86-froyo" for OS "Linux" and Version "Linux 2.6" with RAM as 256 MB and dynamically growing IDE (not SCSI) Harddisk of 2 GB Capacity. Enable both the serial ports (COM1 and COM2) but leave them in "Disconnected" mode. To the above Virtual Machine, attach "froyo-vm-20100812.iso" as CD image to the IDE co...

Operating System: Windows 7 Ultimate 64 bit Download "Java Platform,Standard Edition JDK" (filename: jdk-6u23-windows-i586.exe) from http://www.oracle.com/technetwork/java/javase/downloads/index.html When asked to select the platform, select "Windows" and not "Windows x64" because we want the 32 bit software and not the 64 bit one eventhough our OS is 64 bit. No special installation instruction, just keep clicking next on the installation wizard dialog boxes that pop up. Download "Eclipse IDE for Java Developers" (filename: eclipse-java-helios-SR1-win32.zip) from http://www.eclipse.org/downloads/ Use the 32 bit Eclipse eventhough your OS is 64 bit. Extract the folder "eclipse" from within eclipse-java-helios-SR1-win32.zip to C:\ Rename this "eclipse" folder to "eclipseandroid" in case you want to distinguish it from other installations of eclipse. Run C:\eclipseandroid\eclipse.exe Rename the workspace path...

So the waveform collection wouldnt be complete without the 50Hz AC Mains . Since the oscilloscope I am currently using is USB powered PC based, it can't handle high voltages such as the 230 Volts AC/Hz available in India. So I stuck my probes onto the secondary of a AC/DC step down adapter.. ..connected the oscilloscope to my laptop and observed the waveform and more specifically, its frequency: Just to be safe, I operated the laptop on battery and disconnected the laptop charger from the mains. Next I loaded the AC/DC adapter with a 47 ohms resistor... .. and observed the signal (note the distortion): If you are wondering if (and why) the utility frequency ever changes then the following articles would interest you: Wikipedia article on "Utility Frequency" Increase AC mains frequency? Accuracy and stability of the 50 Hz mains frequency

Waveforms of signal on a 10 Mbps Ethernet CAT5 cable (captured differentially on the RX+ and RX- wires): For the info regarding how I managed to captured this waveform have a look at the usenet discussion here and the supporting info here . Click on the image below to know how I forced my network card to operate in 10 Mbps mode only:

Whenever we press the keys on our touchtone landline phones, it transmits two sine waves simultaneously. The interface at your telephone exchange recognizes the frequencies of both of these waves and hence identifies the key pressed. This is known as Dual-tone multi-frequency signaling . The various combinations of the frequencies of each of the keys are as below: DTMF Frequencies in Hertz       KEY  FREQ1    FREQ2         1    697    1209 2    697    1336 3    697    1477 A    697    1633         4    770    1209 5    770    1336 6    770    1477 B    770    1633         7    852  ...

Here is a printout of screen capture of A and B signals of an RS485 Bus as captured on an oscilloscope (Agilent 54621A). The RS485 Bus usually consists of a twisted pair cable connected to an RS485 Transceiver. In the case, below, a twisted pair cable has not been used - the signals were directly observed at the A and B pins of DS75176 loaded by a 120 ohm resistor and biased by two 560 ohm resistors. The bus is bein operated in half-duplex mode. DS75176 (which is equivalent to MAX485 ) was connected to the UART of Atmega8 AVR Microcontroller. The data being transmitted were the characters: 'a' '0' '1' '2' 'K' 'Q' - in that order. The UART frame format is 8-N-1 and the baud rate is 38.4 kbps. The signals A and B were captured on two different channels both referenced to the common system ground. This waveform was captured while me and my classmates were working on our final year project at the end of our undergraduate engineering cour...

How to observe Spectrograms of various signals or latest pop/techno songs: Buy a Nokia phone - specially the ones like Nokia 5800 or Nokia X6 or any other which are labelled "comes with music" or "music unlimited" Install the nokia support software on your computer - especially the Ovi Player Validate your music coupon and download a few songs from using Ovi Player. This is completely legal. Install Winamp 2.95 (older version). You can get it from oldversion.com here . Start Winamp, go to preferences, set the visualization plug-in to "Spectrum Analyzer + Voiceprint" which is present in the "Nullsoft Tiny Fullscreen 2001" Library Load the song in winamp, play it and press "Ctrl+Shift+K" to watch the live spectrogram of the song. The Spectrogram is updated from left to right. Press "Esc" key to get out of fullscreen mode. If you want to see the voiceprint of your voice, "add a URL" to playlist and type ...