Basics of CDMA

In Code Division Multiple Access (CDMA) systems the narrowband message signals are multiplied by spreading signals. All users in CDMA uses same carrier frequency and can transmit simultaneously. The spreading signals are pseudo random code. The features of CDMA are as follows:

Basics of TDMA

Time Division Multiple Access (TDMA) systems divide the radio spectrum into time slots, and in each time slots only one user is allowed to either transmit or receive. Each user occupies a cyclically repeating time slot. Features of TDMA are as follows:

Basics of FDMA

Frequency Division Multiple Access (FDMA) assigns individual channels to individual users. The users is allocated a unique frequency band or channel. During the period of the call no other users can share the same channel. In Frequency Division Duplexing (FDD) systems the users are assigned a channel as a pair of frequencies; one frequency is used for forward channel, while other is used for reverse channel. The features of FDMA are as follows:

How To Avoid Race Around Condition in JK Flip Flop

  Race around condition is the most important condition in Digital electronics. In J-K Flip flop, when J=K=1 the output changes its state. When a clock pulse width tp is applied the output will change from 1 to 0 after a time interval of Δt, where Δt is the propagation delay through two NAND Gates in series. Now after Δt we have J=K=1, Q=0, After another interval of Δt, output Q will become 1. Hence the output will oscillates back and forth between 0 and 1 in the duration tp of the clock pulse width.

Basic Theorems in Digital Electronics

Digital Electronics is a core and important subject of Electronics and Communication Engineering. Its simple and easy to understand. The theorems used in Digital electronics minimizes the switching function of digital circuits.

The main theorem is "De-Morgan's Theorem"

Voltage-Current (V-I) Characteristics

Voltage and Current (V-I)characteristics of many devices are useful to know the nature of the device. Here are some V-I characteristics

Switches in Electronics

This time we shall be dealing with the practical application of the basic transistors; be it BJT or MOSFET each of these act as a switch in vivid applications. By the not just a switch!! These are high performance switches which work at very high switching speeds...may be in fraction of secs or milli secs!

Now, What do you understand by the term Switch??

Definition:  A switch is a device for making and breaking the connection in an electric circuit.

Diodes: Types and Applications

Diodes is a two terminal electronic device which allows the flow of current in only one direction and high resistance in opposite direction. The most common diode used currently are p-n junction diode. The diodes are of different types as illustrated below:

• p-n junction Diodes
• Avalanche Diodes
• Zener Diodes
• LED(light emitting diode)
• Photo Diodes
• Sckottky Diodes
• Tunnel Diodes
• Gunn Diodes
• Laser Diodes
• Pin Diodes

Analog and Digital Communication...!

The essence of communication is an exchange of information. From the very dawn of human civilizations it has been an endless effort to find means and ways of sharing thoughts, ideas, expressions and messages conveying much value. Language was the first means of communication, be it Arabic or Latin; which was gradually enriched to make the mode of communication more effective. This made possible the exchange of written messages or documented information that could not only be sent to distant locations but could also be handed down the generations and preserved for posterity. Many other modes of sending messages evolved from the early days of human interaction. Tireless endeavors at finding ways and means of conveying information effectively evolved gradually into many time-tested communication techniques.

 The History...

Basic Electronic Devices

The blog will deal with all your basic doubts of basic electronics, so here in this post you will learn some basic electronic devices.
Ever wondered while your faculty suddenly asks you to tell some basic electronic devices, then what you should reply....! The answer is below....

Here is the list of basic electronic devices:

• Resistors
• Capacitors
• Diodes
• Transistors
• Transducers
• Sensors
• Switches
• Detectors 

Resistors: A Resistor is a element which restricts the flow of current and dissipates that energy into heat.

So when a current flows through a resistor then it restricts the flow of current but that energy is converted into heat as energy can neither be destroyed nor created. We can take example of a resistor connected in series with LED (Light emitting diode) to limit the current passing and hence protecting the LED to get damaged.