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HT9580
34
April 28, 2000
Preliminary
The filtered data is used to synchronize an in-
ternal clock generator by monitoring transi-
tions. The recovered clock phase can be
adjusted in steps of 1/8, 3/32, 1/16, or 1/32 bit
period per received bit.
All step size are used when bit synchroniza-
tion has not been achieved, the smallest when
a valid data sequence has been detected.
Erroneous code-words
Upon receipt of erroneous uncorrectable
code-words, call termination occurs according
to the conditions given below:
SPF08 SPF09
Description
0
X
Any two consecutive
code-words or the
code-word directly following
the address code-word in
error
1
0
Anysinglecode-wordinerror
1
1
Any two consecutive
code-words in error
Message receiving mode
The receiving message mode (numeric or al-
pha-numeric) depends on bits SPF16~SPF19.
If one of these bits from SPF16~SPF19 is
cleared to low, the decoder will be in numeric
package receiving mode. Otherwise, the de-
coder is in the alphanumeric receiving mode.
An example is shown below:
Function Bits
Message Re-
ceiving Format
Bit 20 (MSB)
Bit 21 (LSB)
SPF16=0
0
0
Numeric (4-bit)
SPF17=0
0
1
Numeric (4-bit)
SPF18=1
1
0
Alphanumeric
(7-bit)
SPF19=1
1
1
Alphanumeric
(7-bit)
The decoder data output format is deter-
mined by the value SPF16~SPF19. When it is
logic low, the 4-bit (numeric) package will be
selected. Otherwise, the 7-bit (alphanumeric)
packageisselected.Thefollowingtablesillus-
trate the above two different conditions.
Message code-word on the message buffer (numeric receiving mode)
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Error Flag
0
0
0
D3
D2
D1
D0
Message code-word on the message buffer (alphanumeric receiving mode)
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
Bit0
Error Flag
D6
D5
D4
D3
D2
D1
D0
Synch word indication
The synch word recognized by the HT9580 is
the standard POCSAG synchronization
code-word as shown in the following table.
Bit No.
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Bit
0
1
1
1
1
1
0
0
1
1
0
1
0
0
1
0
Bit No.
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
Bit
0
0
0
1
0
1
0
1
1
1
0
1
1
0
0
0