Digital encoders are common electronic circuits used in almost all digital systems today. You can find them in pocket calculators, industrial control panels, navigation electronics, telecommunication devices, etc.
This article will discuss the basics of digital encoders.
What are digital encoders?
Digital encoders are combinational circuits that convert data from one form to another. They take in multiple data inputs and generate a corresponding encoded output—one having reduced number of bits—as per a pre-specified Boolean expression.
For example, if you input an 8-bit data into an encoder, the encoder will convert it into a 3-bit data for further processing and communication.
It’s worth mentioning here that encoders in their most basic configuration only produce a valid output if all of their inputs are mutually exclusive. So we can say that in a way, encoders act as one-hot to binary converters.
But why do we even need encoders?
Every design engineer wants to design a device that uses the least number of lines to transfer data. That’s where digital encoders come in.
By reducing the number of bits, digital encoders enable engineers to design systems that transmit data efficiently and safely using fewer transfer wires.
In addition, digital encoders also help to store data efficiently by shrinking the size of data and facilitating maximum use of the available storage space.
How do digital encoders work?
To understand how digital encoders work, let’s take a look at a 4×2 encoder in action.
All encoders have “2n” input lines and “n” output lines. In case of 4×2 encoder, it has four input lines and two output lines.
The truth table of 4×2 encoder is as follows:
From the table above, we can write the Boolean expression for each output as follows:
X = A + C
Y = A + B
Notice, that at any given instant, only one of the inputs to the encoder is “HIGH”.
Of course, there’s always a possibility that when using input switches, there may be two or more inputs that can be “HIGH” at a single time. For such applications, we use a priority encoder.
A priority encoder works in a similarway to a normal digital encoder. The only difference is, it has internal controls that allow it to prioritize a single “HIGH” input when multiple switches may be active.
Buy high quality encoders at ADSANTEC
At ADSANTEC, we stock the best quality electronic and circuit components—including high performance encoders—for your specialty system design needs. View our product catalogue for more details.