Archive for March, 2007

Fractal antenna constructions

Wednesday, March 28th, 2007

Among usual antennas used in todays data transfer there are also different type of antenas used. First publications about electrodynamic characteristics of fractal structures were published in 1980’s , but first practical approach appeared after 10 years. Dr. Nathan Cohen professor of boston university designed, engineered and patented many practical fractal antenna solutions and founded [...]

Electrical switches principles and switching problems

Thursday, March 22nd, 2007

Switches are important part in electronic systems. It is one of most frequently used human interaction with electronic devices methods. But switches are mechanical component that are vital part of any equipment.
Electrical switches
Electrical switches are as old as electricity. The function is always the same – it makes or breaks current in a circuit. In [...]

Overview of noises in electronic systems

Wednesday, March 21st, 2007

There are several sources of noises in electronic systems. Noises are unwanted signal polluting random or not signals that reduces overall signal quality.
Thermal Johnson/Nyquist noise
This noise is actually discovered by two scientists Johnson who did the experiments and Nyquist who developed the formula. Thermal noise present at all frequencies (has a constant power density at [...]

Multiple controllers in one design

Wednesday, March 21st, 2007

Actually many embedded systems use multiple microcontrollers and microprocessors. This is not about a multi-core processors but several distinct processors used in one design.
Multiprocessor systems allow to distribute computing power among different processors and this way overall speed may be increased, coding simplified and modularity reached. Using multiprocessor embedded design have many benefits. One of [...]

Debugging embedded hardware and software traces

Wednesday, March 21st, 2007

Usually when designing embedded project we typically focus on actual application, but do not pay enough attention to hardware and software debug process. Adding debugging capability to project require some strategy. Simple situation: hardware may not be installed but connected to other circuit when needed. So software must support the functionality regardless of weather or [...]

Long range directional microphones-myth and reality

Wednesday, March 14th, 2007

There are a lot of myths about directed long range microphones. You can here like they can reach distances of 100, 200 and more meters, other say that this is a myth and these numbers are commercial purposes. Lets try mathematically find a proof and see real situation.
Introduction to long range microphones
When talking about directed [...]

xDRV-driver for LPT with interrupt service routine

Wednesday, March 7th, 2007

Driver xDRV.sys is driver developed by Иванов Д. В.(www.pcports.ru) and is capable to work(read write) with any PC port under windows NT, 2000, XP. But main advantage of this driver is that it can catch and handle LPT port interrupts (in this case LPT1 with address 0×378 with IRQ 07).
Program part of xDRV
Lets see [...]

Control LPT port under windows XP using Delphi

Wednesday, March 7th, 2007

Another way of controlling LPT port under Windows 2000 and XP using Delphi language. In this case library inpout32.dll is used which allows controlling LPT port registers.
Ready project for Borland Delphi 7.0 you can download here: Project Files<187.5kB>
And now how to do this from beginning. Start Borland Delphi 7.0 and make simple form where [...]

Controlling external devices using COM port communications programmed using VB language

Wednesday, March 7th, 2007

There are a lot of Radio amateurs that want to control external devices using computer standard ports. One of them is COM poert. Everybody wants things to be ease as people doing electronics are more hardware people not software. COM port is more often used than LPT because COM port is more resistive to bigger [...]

Understanding and conversion different firmware file formats

Monday, March 5th, 2007

Without getting to deep int discussions why there are several firmware formats and extensions used. But fact is that you can face firmware files with extensions like BIN, HEX ir E2P. Lets see how these files look like and how to convert between them.
First of all it is important to mention that all firmware files [...]