EncodersAn encoder can also be described as a combinational circuit that performs the inverse operation of a decoder. An encoder has a maximum of 2^n (or less) input lines and n output lines. In an Encoder, the output lines generate the binary code corresponding to the input value. The following image shows the block diagram of a 4 * 2 encoder with four input and two output lines. The truth table for a 4to2 line encoder can be represented as:
From the truth table, we can write the Boolean function for each output as: D1 = A3 + A2 D0 = A3 + A1 The circuit diagram for a 4to2 line encoder can be represented by using two input OR gates. The most common application of an encoder is the OctaltoBinary encoder. Octal to binary encoder takes eight input lines and generates three output lines. The following image shows the block diagram of an 8 * 3 line encoder. The truth table for an 8 * 3 line encoder can be represented as:
From the truth table, we can write the Boolean function for each output as: x = D4 + D5 + D6 + D7 y = D2 + D3 + D6 + D7 z = D1 + D3 + D5 + D7 The circuit diagram for an 8 * 3 line encoder can be represented by using two input OR gates.
Next TopicMultiplexers
