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I am using HT12E, for a rf transmitter circuit. As per the datasheet HT12E is a 2¹² encoder.

Ideally such an encoder must have 2¹² inputs and 12 outputs. In addition to that all the inputs should be 1 exclusively.

When i look at the IC, I see 12 inputs A0-A7 + AD8-AD11, which go into the transmission gate circuit of the IC.

Can someone help me understand this part of the working ?

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    \$\begingroup\$ I haven't looked, but from your description it appears that "\$2^{12}\$ inputs" (your term) means instead "\$2^{12}\$ symbols." The 12 inputs make sense then. \$\endgroup\$ – jonk Jun 3 at 15:52
  • \$\begingroup\$ that appears to be a type of parallel to serial converter ... it encodes 12 inputs into a bit stream ... 12 inputs and 1 output \$\endgroup\$ – jsotola Jun 3 at 15:54
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You're conflating a couple of definitions of the word "encoder". In this case, the chip is taking 12 binary inputs and encoding them as a serial word along with some synchronization information. The resulting word has 212 different states or values.

There is a different kind of (combinatorial) circuit that accepts 2N separate inputs and encodes the highest-valued one as an N-bit binary number. This is known as a "priority encoder".

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A chip with 212 inputs would have \$ ( {2 ^ {12}} ) ^{12} \$ possible combinations.

A 12-bit chip has 4096 combinations.

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