Fractional Q Formats
A.2.3 Q.31 Format
Q.31 format spans two 16-bit memory words. The 16-bit word stored in the lower memory location contains the 16 least significant bits, and the higher memory location contains the most significant 15 bits and the sign bit. The approximate allowable range of numbers in Q.31 representation is (−1,1) and the finest fractional resolution is 2−31 = 4.66 × 10−10.
Table A−3. Q.31 | Low Memory Location Bit Fields | | | | | | |
| | | | | | | | | | | |
| | Bit | 15 | 14 | 13 | 12 | … | 3 | 2 | 1 | 0 |
| | | | | | | | | | | |
| | Value | Q15 | Q14 | Q13 | Q12 | … | Q3 | Q2 | Q1 | Q0 |
Table A−4. Q.31 | High Memory Location Bit Fields | | | | | | |
| | | | | | | | | | | |
| | Bit | 15 | 14 | 13 | 12 | … | 3 | 2 | 1 | 0 |
| | | | | | | | | | | |
| | Value | S | Q30 | Q29 | Q28 | … | Q19 | Q18 | Q17 | Q16 |
