Digital signalsDigital signals are carried out as a series of "on" and "off" pulses.
They are finite, meaning there is a limited set of values available. It could be just two total possible values for instance 45 and 612 or anything as long as it’s not ∞ (infinity). For that reason in digital technology, the information is structured in a binary format (consisting of 0 and 1) and creates square-like waves. Digital signals have a 'immunity' to other forms of radiation because they can only indulge limited information, therefore are not as affected by noise. This results into hearing clearer outcomes like when listening to a phone conversation. |
Most commonly digital signals consists of two values, for instance 0V or 5V. Timing graphs of these signals look like square waves.
The conversion of analog to digital causes small sections of information being lost. Because analog signals are extremely specific, digital signals have bands to categorise whether a number is high, low or undefined. |
Why do digital devices need to convert analog signals to digital?
One reason is to avoid corruption of the signal. This is can be shown by CDs (digital) compared to vinyl records (analog). On a vinyl record, the pressure of the needle eventually wears away, causing the music on the album to become poor quality. On a CD, the digital data that the laser is reading is either correct or incorrect. A digital device can know if the data is incorrect using special techniques like checksum. If it is incorrect, error correcting codes can be used to retrieve the valid data.
Another reason is a lack of noise. On a vinyl record or a cassette tape (which are analog), there is a hint of hissing that degrades the analog signal because of the surrounding signals/radiations. A CD has no hiss because the digital signal is immune to this effect.
A third reason is compression. With digital data, there are a variety of compression algorithms that can be used to shrink the signal. The sound quality of an MP3 file is good despite being much smaller than the uncompressed song on a CD. Cell phones and DVDs also depend on compression. Without compression, it would be impossible to fit a movie on a DVD.
Another reason is a lack of noise. On a vinyl record or a cassette tape (which are analog), there is a hint of hissing that degrades the analog signal because of the surrounding signals/radiations. A CD has no hiss because the digital signal is immune to this effect.
A third reason is compression. With digital data, there are a variety of compression algorithms that can be used to shrink the signal. The sound quality of an MP3 file is good despite being much smaller than the uncompressed song on a CD. Cell phones and DVDs also depend on compression. Without compression, it would be impossible to fit a movie on a DVD.