My students (children) ask me what is the difference between analog and digital. Is it a good question? We will answer him how? clear and easy…
Have we heard each other? Both the words such as any audio or video is transformed into electrical signals.
And do you know two words are different?
In short, analog technology information is translated into a signal that varying amplitude. And It should be smooth and continuous.
In digital technology, information is into one and zero formats. We called binary. Each bit is two distinct amplitudes.
What is an Analog Signal?
It is a continuous Data. There is a varying signal amplitude. The change in signal size is gradual and a curve.
Which one time-varying quantity represents another time-based variable.
We will see this type of signal works around us, with physical values and natural. For example, frequency, voice, wind, wave, weight, lighting, etc.
Can you see a clearer image yet?
In electronics also there is a lot of analog forms. For example:
The output from LDR (light sensor), or Microphone, Audio, Any frequency, etc.
A power amplifier
It is another example of an analog system. The power amplifier will produce the output voltage. Which any value within the range of its power supply.
It can display any value within the range available on the scale. However, accuracy is limited by our ability to read.
Look at Galvanometer 0-1mA
Learn: How to use an analog meter
For example, The meter shows 0.25mA. Its needle is pointed at about halfway between 0.2mA and 0.4mA. But we can’t read the scale more than half the mark.
Noise in Analog circuits
All electronic circuits suffer from noise signals. This is an unwanted signal, mixed with the desired signal.
For example, an amplifier can pick up and hum from AC mains (50Hz AC main). It is difficult to eliminate the noise from the Analog signal. Because it is difficult to distinguish between interference and the desired signal
Pros of Analog Signals
- Easier in processing
- Best suited for audio and video transmission.
- It has a low cost and is portable.
- It has a much higher density so that it can present more refined information.
- Not necessary to buy a new graphics board.
- Uses less bandwidth than digital sounds
- Provide more accurate representation of a sound
- It is the natural form of a sound.
Cons of Analog Signals
- Lower quality signal than digital.
- The cables are sensitive to external influences.
- The cost of the Analog wire is high and not easily portable.
- Low availability of models with digital interfaces.
- Recording analog sound on tape is quite expensive if the tape is damaged
- It offers limitations in editing
- The tape is becoming hard to find
- It is quite difficult to synchronize analog sound
- Quality is easily lost
- Data can become corrupted
- Plenty of recording devices and formats which can become confusing to store a digital signal
- Digital sounds can cut an analog sound wave which means that you can’t get a perfect reproduction of a sound
- Offers poor multi-user interfaces
What is Digital Signal?
The signals associated with Discrete Data. Have a certain size. They may jump between two values: the highest signal and the lowest signal.
Or discrete steps like either 0V or 5V. Timing graphs of these signals look like square waves. Or we called Logic states.
Look at the square wave signal
Digital systems are made up of devices such as logic gates, flip-flops, shift registers, and counters. Computers are an example of digital systems.
Today we prefer to use a Microcontroller like Arduino to replace a normal analog.
What is more?
An example of a digital circuit closest to us is a digital multimeter. We can use it to read many values and have higher accuracy than an analog meter.
Credit: Photo Equus
Not only that I want to explain to you about this, too
Most digital systems use a simple signal type. Which has only two values This type of signal is called the logic signal. Because these two values (or status) can be called “true” and “false”. Normally the positive power supply voltage is + Vs instead of true, and 0V represents false.
Obvious advantages of a digital signal, we can get rid of the interference signal easily. It is convenient to distinguish the desired signal. Which it has a specific value.
For example, If the logic signal means + 5V (True) or 0V (False) .. noise is as high as 2.5V. We can cut it out. We can isolate all voltages above 2.5V, is True and the voltage less than 2.5V are False.
Pros of Digital Signals
- Digital data can be easily compressed.
- Any information in the digital form can be encrypted.
- Equipment that uses digital signals is more common and less expensive.
- Digital signal makes running instruments free from observation errors like parallax and approximation errors.
- A lot of editing tools are available
- You can edit the sound without altering the original copy
- Easy to transmit the data over networks
Cons of Digital Signals
- Sampling may cause loss of information.
- A/D and D/A demands mixed-signal hardware
- Processor speed is limited
- Develop quantization and round-off errors
- It requires greater bandwidth
- Systems and processing is more complex.
Difference Between Analog and Digital
By the way, let’s compare them.
|Signal||Continuous signal||time separated signals|
|Waves||sine waves||square waves|
|Errors||Analog instruments usually have a scale which is cramped at lower end and give considerable observational errors.||Digital instruments are free from observational errors like parallax and approximation errors.|
|Impedance||Low||High order of 100 Megaohm|
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