Agilent Technologies 4339B, Operation Manual

Page: 197 / 287

4339B Data Transfer F ormat
REAL
Figure 5-12. Real Data F ormat
This data eld is initiated by a unique code , the number sign (#). The second byte ,
\<num digit>" designates the number of the bytes for the \<num bytes>". \<num bytes>"
designates \<data bytes>" length. \<new line>&^END " is the response message terminator .
\<data bytes>" contains the data in IEEE 754 oating point numbers of 64-bits . This is the
same data format used by the HP T echnical computers , such as the HP 9000 series 200/300
computers .
Bit No . 7 6 5 4 3 2 1 0
First byte sent S E
10
E
9
E
8
E
7
E
6
E
5
E
4
Second byte sent E
3
E
2
E
1
E
0
F
51
F
50
F
49
F
48
.
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Eighth (last) byte sent F
7
F
6
F
5
F
4
F
3
F
2
F
1
F
0
Where ,
S : V alue of sign part (binary)
E
n
: V alue of exponential part (binary)
F
n
: V alue of fractional part (binary)
EXP : Decimal expression of exponential part
f : Decimal expression of fractional part
The real number RN represented in oating point format is provided by the following formula:
When 0 < EXP < 2047 (11111111111
2
)
RN = (01)
S
2 2
(EXP-1023)
2 (1 + f/2
52
)
When EXP = 0
RN = (01)
S
2 2
-1022
2 (f/2
52
)
When EXP = 0, f = 0
RN = 0
F or example , S = 1
EXP = 1023 (01111111111
2
)
f = 2
51
(1000 00000000 00000000 00000000 00000000 00000000 00000000
2
)
RN = (01)
1
2 2
(1023 01023)
2 (1 + 2
51
/2
52
)
= 01 2 1 2 1.5
= 01.5
GPIB Reference 5-49