In signed binary number to decimal conversion can use similar technique.
For examaple, 1000 binary number the MSB is "1". The digit weight is 23 or 8. This
signed binary number is equal -8. In conversion the remain 3 bit is positive value. Thus,
the conversion is -8 + 0 = -8.
Next example, convert 1101 signed number to decimal. At MSB is -8 and 3 last right
bit is positive as +5 [101 = (22
x 0) + (21 x 0) + (20
x 1)]. The conversion is -8 + 5 = -3