Digital And Analog Devices - Ts Read

Saturday, 27 May 2017

Digital And Analog Devices

Hello friends welcome to 

Digital Devices

A digital device is the device that involves the use of digital signals at the time of working.

Digital Signal 

In the digital system of signals , there are only two states of the signal - present or not present , true or false , 1or 0.

Computer is a digital divice . Everything that is to be stored in the computer is represented in the from of 0 or 1 , i.e., binary form . In between  these  two conditions, there is no other state of any kind.

Analog Devices

Analog devices is a devices that uses analog signal at the times of working .

Analog signal

Analog signals are continuous  signals , like pressure and temperature. The telephone system is an analog device.


Communication refers to sending , receiving or processing information by electrical means . If you have a digital device, you can communicate directly with another digital device.

If you have an analog device, you can communicate directly with another analog device.
If you have digital device and want to communicate with an analog device and vice versa , you need a device to connect the two because their signals are different and need a communicator or convertor.


You already know that a digital device and an analog device cannot communicate with each other directly other directly because their signals are of different kinds.

A convertor is a device that converts signals of one device to the signals of the other device. Convertors can be of two types :

1. Analog to Digital Convertor (ADC)
2.Digital to Analog Convertor (DAC)

1. Analog to Digital Convertor (ADC)

It is a electronic circuit that converts an analog signal into a digital signal. for example , A softwere is now available which converts our (Analog) voice into digital data in our computer.

Another example is physical quantities , like - temperature and pressure are measured through analog signals. So, their information is analog information . if you want to use this information into a computer , you have to pass this signal through an ADC . These analog signals are than converted into digital signals.

2. Digital to Analog convertor (DAC)

It is an electric circuit that converts a digital signal into a analog signal. For example , Computer works on digital signals . These signals can be used to produce sound for a telephone set, a loudspeaker. These signals are converted into analog signals by means of DAC. You must have seen a fascimile machine (FAX) , it is a familiar device and found in most offices. It uses both types of convertors, a DAC to feed a written form .


The word MODEM is formed from the inital letters of two words - MODULATOR and DEMODULATOR.

Modulator comes from the word 'modulate' which means 'to convert' . So a modulator is a device used to convert analog signals into digital form.

So modulation means conversion of digital signals to analog signals, and demodulation is the conversion of analog signals to digital signals.

Modem is a very important device of a communication system. It is used for communication between different computers through a telephone line. A modem converts digital signals received from a computer into analog signals for a telephone line.Also it converts the analog signals received back from the telephone line into digital signals for the computer.

Types of modems :

1. External 
2. Internal

External modem is placed outside the system unit. It is connected to the motherboad through a port .

Internal modem is in the form of a card and placed inside the system unit.

Both high speed and low speed modems are available . Modem speed is measured in bits per second (bps).

Low speed modems are modems with a speed of less than 1800 bps.

High speed modems have a speed of more than the 1800 bps.

you should have a modem with a speed of  at least 14400 bps.

Modem speed of 33,600 bps and heigher are now available .

Modem speed is also measured in kilo bits per second (kbps). For example , A 33,600 bps modem is also referred as a 33.6 kbps modem.

Uploading and Downloading


Uploading is the process by which a user sends information form his PC to another PC through a modem.


Downloading is the process in which a  user receives information from another pc through a modem for his own pc.

Thus you can see that with the devices mentioned in this blog you can communicate with people all across the world in a matter of a few seconds.