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Appendix C. GOES Data Formats
C-4
When transmitted in a Pseudo Binary format, the 16 bits are encoded within 3
bytes. They are spread across the lower 6 bits of each character as shown in the
following table. For example, the value of 12.34 would be encoded as follows.
Char1 = D Char2 = S Char3 = R
p 1 0 0 b16 b15 b14 b13 p 1 b12 b11 b10 b9 b8 b7 P 1 b6 b5 b4 b3 b2 b1
0 1 0 0
0 1 0 0 0 1 0 1 0 0 1 1 0 1 0 1 0 0 1 0
C.3.2 18-bit Integer
The 18-bit integer data format is used to transmit a signed or unsigned integer.
The 18 bits are encoded across 3 bytes. When signed, the value is encoded
using a two’s complement representation. As an integer cannot directly
represent a fractional number, measurements are often scaled before storing to
the GOES data table. For example, a water level surface elevation of 123.45 ft
would first be multiplied by 100 and the resulting integer of 12345 would be
stored for transmission with the following encoding.
Char1 = C Char2 = @ Char3 = y
p 1 b18 b17 b16 b15 b14 b13 p 1 b12 b11 b10 b9 b8 b7 p 1 b6 b5 b4 b3 b2 b1
0 1 0 0 0 0 1 1 0 1 0 0 0 0 0 0 0 1 1 1 1 0 0 1
C.3.3 Additional Pseudo Binary Representations
Other Pseudo Binary representations, such as 6, 12, and 24 bit integers, can be
formed and transmitted using CRBasic.