Tuesday, 30 May 2017
Tuesday, 9 May 2017
Analogue Signal:
Our world is analogue, most things we relate with has
infinite values. Working with electronics with deal with both digital and
analogue signals. An electronics system that deals with analogue signals
are referred to as analogue system.
Come to think of it what is (are) signals?
Signals are time varying quantities. That is, there values
changes as time changes.
An example of such in electronics is voltage
(or Current),
when we talk of signal just think voltage.
Signals are passed between devices in order to send and
receive information, which might be video, audio, or some sort of encoded data.
While these signals may be limited to a range of
maximum and minimum values, there are still an infinite number of possible
values within that range.
Example of analogue signal are Audio and Video signal.
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| Analogue devices |
Digital Signals
Digital signals must have a finite set of possible values.
The number of values in the set can be anywhere between two and
a-very-large-number-that’s-not-infinity. Most commonly digital signals will be
one of two values – like either 0V or 5V. Timing graphs of these
signals look like square waves.
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| Digital device |
Analogue and Digital Circuits
Analogue Electronics
Most of the fundamental electronic components – resistors, capacitors, inductors, diodes, transistors, and
operational amplifiers – are all inherently analogue. Circuits built with a
combination of solely these components are usually analogue. Analogue circuits are much more difficult to design than those which
accomplish the same task digitally.
 |
| Analogue Signal |
Digital Electronics
Digital circuits operate using digital, discrete signals.
These circuits are usually made of a combination of transistors and logic-gates and,
at higher levels, microcontrollers or other computing chips. Most processors,
whether they’re big beefy processors in your computer, or tiny little
microcontrollers, operate in the digital realm.
Digital circuits
usually use a binary scheme
for digital signalling. These systems assign two different voltages as two
different logic-level –
a high voltage (usually 5V, 3.3V, or 1.8V) represents one value and a low
voltage (usually 0V) represents the other.
Although digital
circuits are generally easier to design, they do tend to be a bit more
expensive than an equally tasked analog circuit.
 |
| Digital Signal |
Digital information has certain properties that distinguish it from analogue communication methods. These include
· Synchronisation – digital communication
uses specific synchronisation sequences for determining synchronisation.
· Language – digital communications requires
a language which should be possessed by both sender and receiver and should
specify meaning of symbol sequences.
· Errors – disturbances in analogue communication causes errors in actual intended communication but disturbances
in digital communication does not cause errors enabling error free
communication. Errors should be able to substitute, insert or delete symbols to
be expressed.
· Copying – analogue communication copies are
quality wise not as good as their originals while due to error free digital
communication, copies can be made indefinitely.
· Granularity – for a continuously variable
analogue value to be represented in digital form there occur quantization error
which is difference in actual analogue value and digital representation and this
property of digital communication is known as granularity.
Further reading:
1. Digital Electronics for Science
Introduction to Electronic Logic for Science
1. Analogue Versus Digital Electronics
2. Number Systems
3. Binary Codes
4. Digital Arithmetic
5. Boolean Algebra
6. Logic gates.
7. Karnaugh Map Simplification Method
Collaborative Learning
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