Digital technology, computer inferences

TECHNOLOGY

By MICHAEL JOHN UGLO
WELCOME all to our very first lecture on digital technology and computers.
It is going to be a long journey and please bear with me if you have been ambitious to master the above field or at least wanted to know how digital technology has inundated this world telling us to live by its ways. Everything we do is digital at least if you want to get an easy way out of anything.
Now let’s go for the excursion to examine the basis and how computers have become the common medium for this technology.
Digital technology takes the centre stage for the 21st century as we mentioned in our introductory remarks above in the world in which we are living in at the moment. In the technological explosion of this era, it is the creation, processing and transmission of data and information for communication in all areas of life whether it be from people to people via the communication mediums and electronic devices as well as embedded devices programmed to communicate with each other from a wider world.
To illuminate further, we have to acclimatise and be acquainted with the underlying mechanisms and the founding principles that allow for this technology to takeoff and thrive.
First and foremost, the idea that comes to mind is digital electronics. The term digital refers to digits and these are numbers and in digital electronics are the numbers zero (0) and one (1). Since these two numbers are used throughout, this forms the basis for the numbering system called the binary numbering system and has a base two (2).
There are other numbering systems like the decimal numbering system which we are all familiar with ranging from 0 to 9 with a base 10 and octal numbering system which starts from 0 to 7 with a base 8 and hexadecimal numbering system from 0 to 9 and A to F with a base 16. Electronics is the use of the energy bearing sub-atomic particles called electrons that are manipulated as a tool to produce breathtaking results which can also use all of these numbering systems uniting digital logic and arithmetic.
Digital electronics can be seen as signals generated from digital devices apart from the analog signals. These signals (digital) are produced from very large alignments of logic gates that perform the Boolean logic functions. Some examples of the logic gates include the AND gates, OR gates, NOR gates, XOR gates, NAND gates and so on.
There are 16 different combinations for these gates used in the electronics industry. The word Boolean is taken from the logic operations in the binary numbering system involving zeros (0s) and ones (1s). The analog signals as in currents and voltages or pneumatics or as pressures, light as in optics with energies such as infrared as well as temperatures can all be quantised and therefore produce the digital signals.

The quantised signals in digital format command the advantage that it is less prone to errors as long as the zeros and ones are not degraded by noise conditions or made less apparent by noise. In highly degraded conditions digital signals can still produce error-free results compared with analog signals. These signals therefore are easily used to come up with many products, whether these be in audio, video or textual.
It is this overriding reason for digital technology to be so popular that revolutionises the world today as being the digital age. Even in degradation forms, the redundancies found in the digital circuits as built in the hardware allow it to be more resilient and robust to transmit information with very high precision and accuracy with very little error in areas as long-distance transmissions.
Unlike the analog mode of transmissions, it forms the premise that the digital system has a higher noise immunity such as the electromagnetic interferences (EMIs) than the analog system. These characteristics outdo the information manipulation, whether it be processing, transmission and reception of data in the analog mode of communication with their circuits. The probability of error conditions can be very high in analog systems with wearing and tearing while digital system is not further contributing to its robustness.
The quantisation errors result from the process of converting indiscrete or continuous signals from analog devices into discrete or discontinuous signals. This is an averaging process and so to get a much improved and correct information without errors there has to be so many digital data to improve this averaging process so the errors are minimised to the lowest mathematical asymptote possible.
For communication’s effectiveness, the entropy of data is considered and embraced as spelled out in the Shannon’s Communication Theory. Hence, the scalability of the system is effectively bearing results here when it comes to higher resolution of images. It implies that one can zoom to any sizes without loss of any detail or resolution such as the loss of integral pixels that comprise the much-needed details. These errors can also be corrected with the introduction of measures such as the parity bits. These checksums detect if messages are received correctly or not with the depiction of the odd or even parity bit signatures.
If an error is found, a command such as a request is sent to the sender for the message to be retransmitted. Otherwise, a correction is effected on the fly by the redundancies built in the circuitries. The many hardware circuits with the redundancies contribute to the robustness of the system’s fidelity for higher reliability. The particular understanding illuminated here is any error in the 1s and 0s as one in place of another can have not so much pronounced effect.
However, in cliff effects, a digital system with compressed data to save time and space for its transmission can have acute adverse effects. In such a case, an error with a 1 or a 0 in substitution for another can have very serious effects in producing so much misinformation and misrepresentation.
In the digital with specifically the computer-controlled systems, it makes the job easier for the products to be purchase from the manufacturer. The hardware is permanently designed and it is only the software that can be corrected when faults occur or surface. These can be programmed, reprogrammed or altered in cases of culpabilities to whatever mode as desired to suit one’s needs. Akin to this is the manner in which the digital circuits are constructed.

Logic gates make up the digital circuits and are made on a silicon substrate called a chip or a computer chip.
The creation of the information can be through the combinational logic of the Boolean functions. It was previously the use of thermionic valves in this application. However, today it is the advent of the transistors and use that allow for so much compaction into a small space. This enables production of immense information with in-depth details and resolution. The logic gates are designed also in programmable logic devices known as PLDs. These are the ready-made separate devices that work on a relational mode with a look-up table and can be programmed to a customer’s needs without changing the wirings built from it.
In small scale applications, the PLDs are normally preferred than the direct use as seen in the combinational logic functions performed by the logic gates. PLDs are designed using software called the electronic design automation software which are used to produce those various constructions called integrated circuits known as the ICs. The ICs are then combined on a circuit board interconnected by traces of copper or copper atoms to form a printed circuit board. The ICs can seem very complex as a result of the redundancies and also the built in circuitry for heat sinks to quell the heat generated from it.
With the help of computer design systems, these complex, redundancy hardware can be simplified with techniques such as the Quine-McCluskey algorithm, Karnaugh maps, binary decision diagrams and others like heuristic computer search methods and the Boolean algebra logic functions. The software engineers and electricians use ladder logics to do the programming in pervasive computing and embedded devices where microcontrollers and the programmable logic controllers perform the digital logic functions for complex systems.
The synchronous and asynchronous systems are shown under the sequential systems versus a combinational system which gives output based on the present input. The sequential systems operate as a state machine for their design and behaviour as some of their outputs are fed back as inputs. Hence, its outputs depend on the present inputs as well as the past inputs to perform its various sequential operations. These digital systems are represented with truth tables in the form of logic gates with various shapes.
The logic gates account for high level representations and transistors like the thermionic valves for the low-level representations. The synchronous system design consists of bistable multivibrators known as flipflops. These change state or latch as a bit in a two state voltage or current as data storage at a ticking of a clock from a rising or falling of an enabled signal.

Next week: Form of digital electronics
My Prayer for PNG today is: “If when you give the best of your service. Telling the world that the Savior has come. Be not dismayed when men don’t believe you. He’ll understand and say “well done”.”

• Michael Uglo is a science textbook author and lecturer in avionics, auto-piloting and aircraft engineering. Please email comments to: [email protected]