Decoding floating point numbers, Waveace remote control – Teledyne LeCroy WaveAce 1000_2000 Remote Control User Manual

Page 90

WaveAce Remote Control

; remote command COMM_FORMAT.

; text arbitrary length text string

; (maximum 160)

; unit_definition a unit definition consists of a 48 character

; ASCII string terminated with a null byte

; for the unit name.

Decoding Floating Point Numbers

Single precision values are held in four bytes. If these are arranged in decreasing value order we get

the following bits:

bit 31, bit 30, bit 29, bit 28 . . . . . bit 3, bit 2, bit 1, bit 0

NOTE: If the byte order command CORD is set for low byte first, the bytes as received in a waveform descriptor

are received in reverse order. However, 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

constructed as follows:

S = (-1)

E = 2

(e - 127)

F = 1 + f

, and

are calculated directly from the 32 bits. The following diagram illustrates the calculation of

the vertical gain example:

920836 Rev B