Conversion into the Q31 Format

1. What is Q31 format?
2. How to convert float to Q15?
3. What is a Q15 type?
4. How do you convert a fixed point to a floating point?

What is Q31 format?

Representation in fixed point:

Consider floating point number 0.5 . To represent this number in Q31 format (31 bits for fractional part), the number has to be multiplied by 231. Hence, 0.5 can be represented in Q31 format as 0.5* 231=1073741824.

How to convert float to Q15?

The equation used for the conversion process is: pDst[n] = (q15_t)(pSrc[n] * 32768); 0 <= n < blockSize. The function uses saturating arithmetic. Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.

What is a Q15 type?

For example, the Q15 is a popular format in which the most significant bit is the sign bit, followed by 15 bits of fraction. The Q15 number has a decimal range between –1 and 0.9999 (0x8000 to 0x7FFF). This Q-value specifies how many binary digits are allocated for the fractional portion of the number.

How do you convert a fixed point to a floating point?

Converting from fixed-point to floating-point

Divide the number by 2^n (2 to the power of n).