Page 14 - DCAP105_WORKSHOP_ON_COMPUTER_HARDWARE_AND_NETWORK

Workshop on Computer Hardware and Network

Notes Voice-input Devices

These devices can recognize the human voice. Voice recognition techniques, along with several
other techniques to convert the voice signals to appropriate words and desire the correct meaning
of words, are comprehensive speech recognition system. Today devices are available to recognize
and interpret human voices within a limited scope of operation. They seem to be very useful but
are not popular due to storage of limited vocabularies and variations in the way of pronouncing
words by different persons.

Digital Camera

A type of camera that stores the pictures or video it takes in electronic format instead of to film.
There are several features that make digital cameras a popular choice when compared to film
cameras. First, the feature often enjoyed the most is the LCD display on the digital camera. This
display allows users to view photos or video after the picture or video has been taken, which
means if you take a picture and don’t like the results, you can delete it; or if you do like the
picture, you can easily show it to other people. Another nice feature with digital cameras is the
ability to take dozens, sometimes hundreds of different pictures.

1.1.3 Output Devices

Once data are processed, output devices translate the language of bits into a form humans can
understand. Output devices are divided into two basic categories: those that produce hard copy,
including printers and plotters; and those that produce soft (digital) copy, including monitors
(the most commonly used output devices. The output normally can be produced in two ways -
either on a display unit/device or on a paper. Other kinds of output as speech output, is also
being used in certain applications.
Let us now discuss various output devices:

Monitors

Visual Display Unit (VDU), commonly called as monitor is the main output device of a computer.
It consists of a Cathode Ray Tube (CRT), which displays characters as an output. It forms images
from tiny dots, called pixels that are arranged in a rectangular form. The sharpness of the image
(screen resolution) depends upon the number of pixels.
There are different kinds of monitors depending upon the number of pixels. Depending upon
the resolution, monitors can be classified as follows:

(a) CGA (Colour Graphics Adapter)
(b) MDA (Monochrome Display Adapter)
(c) HGA (Hercules Graphics Adapter)
(d) EGA (Enhanced Graphics Adapter)
(e) VGA (Video Graphics Adapter)

(f) SVGA (Super VGA)
The differences between these monitors are summarised in Table 1.1. Depending upon the
colour of display, monitors can be classified as Monochrome (with single colour black/white
display) and Colour (with all colours display) Monitors. The pictures of two different models of
color monitors are shown in Figure 1.9.

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