Table of Contents
Advertisement
APPENDIX
C.
BINARYTELECOMMUNICATIONS
HIRESOLUTION FORMAT
Continuing
to use the A-H bit representation, the four byte number
is
shown below as two
two byte pairs.
ABO111GH XXXXXXXX OO1111GH
XXXXXXXX
BITS, 1ST BYTE,
lST
PAIR
CDEF=0111
B
G,H,A,
2nd byte
ABCDEF=001111
G
H
CAMPBELL SCIENTIFIC defines
the largest
allowable range of
a high resolution number to
be 99999.
Interpretation
of
the decimal locator for
a
4 byte
data
value
is
given
below.
The decimal
equivalent of bits GH
is
the negative exponent
to
the base
10.
DESCRIPTION
Code
designating 1st byte pair
of
four byte number.
Polarity,0=+, 1=-.
Decimal locator as defined below.
16th
-
gth bit (left
to right) of
17
bit binary value.
Code designating 2nd byte pair
of
four byte number.
Unused
bit.
17th
and MSB
of
17
bit binary value.
8th
-
1st bit
of
17
bit bina
BITS
GHA
000
001
010
011
100
101
DECIMAL FORMAT
5
digits
XXXXX.
XXXX.X
XXX.XX
XX.XXX
X.XXXX
.XXXXX
signature of
the received data and comparing
it
to the
transmitted signature,
it
can be
determined whether
the data was received
correctly.
SIGNATURE ALGORITHM
51,S0
represent
the high and low
bytes
of
the signature,
respectively
M
represents
a
transmitted data
byte
represents the existing byte
represents
the new byte
represents
a
temporary
represents the
carry
bit
from
a
shift operation
1.
The signature is initialized
with both bytes
set
to hexadecimal AA.
S1(n)=Ss(n)=44
2.
When
atransmitted byte, M(n+1),
is
received, form
a new high signature byte
setting
it
equal
to
the existing low byte.
Save the old high byte
for later
use.
n
n+1
T
c
C.3
GENERATION OF SIGNATURE
At the end
of abinary
transmission, a signature
is
sent.
The
signature
is a
2 byte integer value
which
is a
function
of
the data and the
sequence
of
data
in
the output
array.
lt
is
derived with an algorithm that assures a
99.998% probability of detecting
a
change
in
the
data
or its sequence. The 21X calculates the
signature using each transmitted byte except
the
2 byte signature
itself.
By
calculating the
c-4
Advertisement
Table of Contents
