binary point

The binary point is simply the binary equivalent of the decimal point. It is used in textual representations of binary numbers to designate the transisition from integer digit locations (where values represent non-negative powers of 2) to fractional digit locations (where values represent negative powers of 2).

Example: The binary number 1101.101 has the following digits:

power of 2:   3  2  1  0    -1 -2 -3    
binary digit: 1  1  0  1  .  1  0  1

And has a decimal value of:

= 1*2^3 + 1*2^2 + 0*2^1 + 1*2^0 + 1*2^-1 + 0*2^-2 + 1*2^-3
= 1*8   + 1*4   + 0*2   + 1*1   + 1*0.5  + 0*0.25 + 1*0.125
=   8   +   4   +   0   +   1   +   0.5  +   0    +   0.125
= 13.625

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