SM8211 Просмотр технического описания (PDF) - Nippon Precision Circuits
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SM8211 Datasheet PDF : 22 Pages
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SM8211M
Code words (address and message signals)
Each code word comprises 32 bits as shown in table 2.
Table 2. Code word format
Code word
Address signal
1 (MSB)1
2 to 192
Bit number
20, 212
Function bits
20 21
Function
0
Address bits
0
0
0
1
A call
B call
1
0
C call
1
1
D call
22 to 313
32 (LSB)4
Check bits Even-parity bit
Message signal
1
Message bits
Check bits Even-parity bit
1. The MSB is the address/message code word control bit. It is 0 for an address signal, and 1 for a message signal.
2. Bits 2 to 21 contain the address or message information.
3. Bits 22 to 31 are BCH(31,21) format generated check bits, where BCH(n,k) = BCH(word length, number of information bits).
4. The LSB is an even-parity bit for bits 1 to 31.
Call number to call sign conversion
This conversion expands a 7-digit decimal call num-
ber into a 21-bit binary call sign, as shown in figure
2.
After expansion, the high-order 18 bits are assigned
to bits 2 to 19 (address signal), and the low-order 3
bits are the user-defined frame identification pattern,
which is stored in ID-ROM. The two function bits
define which of four call functions is active.
7-digit decimal call
1
2
3
4
5
6
7
signal (gap code)
MSB
LSB
21-bit binary 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
conversion
Call sign
1
Bits 2 to 19 (18 bits)
20 21
Frame
identificaton
pattern
Bits 22 to 31 (10 bits)
32
Flag:
0 = address signal
1 = message signal
Function bits
BCH(31,21) generated check bits
Figure 2. Call number to call sign conversion
Even-parity bit
(for bits 1 to 31)
NIPPON PRECISION CIRCUITS—6
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