| Octet No. | Contents |
|---|---|
| 12-15 |
Reference value (R) (IEEE 32-bit floating-point value) |
| 16-17 |
Binary scale factor (E) |
| 18-19 |
Decimal scale factor (D) |
| 20 | Number of bits used for each packed value (field width) |
| 21 | Bi-Fourier sub-truncation type see Code Table 5.25) |
| 22 | Packing mode for axes see Code Table 5.26) |
| 23-26 | >P – Laplacian scaling factor (expressed in 10–6 units) |
| 27-28 | NS – bi-Fourier resolution parameter of the unpacked subset (see Note 1) |
| 29-30 | MS – bi-Fourier resolution parameter of the unpacked subset (see Note 1) |
| 31-34 | S – total number of values in the unpacked subset (see Note 1) |
| 35 | Precision of the unpacked subset (see Code Table 5.7) |
| Notes: (1) The unpacked subset is a set of values defined in the same way as the full set of values (on a spectrum limited to NS and MS), but on which scaling and packing are not applied. Associated values are stored in octets 6 onwards of Section 7. (2) The remaining coefficients are multiplied by (n2+m2)P, scaled and packed. The operator associated with this multiplication is derived from the Laplacian operator. (3) The retrieval formula for a coefficient of wave number n is then: Y = (R + X x 2E) x 10–D x (n2+m2)-P where X is the packed scaled value associated with the coefficient. |