I'm trying to understand the professor who wrote about Q2-fixed-point number 1.01 and 1.11 which should be multiplied. I don't understand anything.
Multiply the Q2-fixed-point number 1.01 and 1.11 and give the result as a Q4-number. Answer:
1.01 * 1.10 ----------- 0.01 (2-komplement of 1.01) 0 1.1111 ----------- 10.0011 (sign extension) 0.0011
The result of the multiplication is a positive number. Thus 1.01 is negated by adding the boolean complement to 1. The final result is 0.011. This can be verified using decimal multiplication. The Q2-number 1.01 is -0.75 in decimal base 10 and the Q2-number 1.10 is -0.5 in decimal. Thus the result is 0.375 which is represented as the Q4-number 0.11.
I don't understand the above at all. I understand that 1.01 is -0.75 and that 1.10 is -0.5_10 in decimal but why use 1.10, where does it come from? Why use the 2-complement in the first place? What does the calculation mean? What does the zero mean? It is the most confusing "answer" I've ever seen.