Manual

Waveform Template
WM-RCM-E Rev D ISSUED: February 2005 291
DECODING FLOATING POINT NUMBERS
Single precision values are held in four bytes. If these are arranged in decreasing order of value we get the
following bits:
bit 31, bit 30, bit 29, bit 28 . . . . . bit 3, bit 2, bit 1, bit 0
We must remember that if the byte order command CORD has been set for low byte first, the bytes as
received in a waveform descriptor will be received in the reverse order. But within a byte, the bits keep their
order, highest at the left as expected.
From these bits we are to construct three numbers that are to be multiplied together: S x E x F. These in turn
are constructed as follows:
S = (-1)
s
E = 2
(e - 127)
F = 1 + f
and it is s, e, and f that are calculated directly from the 32 bits. The diagram below illustrates the calculation of
the vertical gain example of Chapter 4.