MAS9191AJ MAS [Micro Analog systems], MAS9191AJ Datasheet - Page 15

• Manufacturer Part Number: MAS9191AJ
• Description: Single Chip AMPS/ETACS/NAMPS Audio/Data Processor
• Manufacturer: MAS [Micro Analog systems]

FUNCTIONS
◆
Reverse voice channel data format for narrow band.
Sync word = 011001010110101001100110100110
The data contains 36 data bits and 12 parity bits. The
transmitted data is 100 bits/sec Manchester code.
DSAT, DST and SYNC WORD are transmitted as
200 bits/sec NRZ code. The DSAT on the TX side is
similar to the DSAT on RX side. However, under
certain conditions the inverted DSAT, or DST (Digital
Signaling Tone), must be transmitted. The DST is
one of seven 24-bit digital sequences consisting of
MAS9191A does not include frame coding logic for
narrow band operation. The DSAT, DST, SYNC
WORD and DATA must be generated by micro
controller. The BCH function must also be performed
by the micro controller using the following algorithm:
Data Transmission in Narrow Band mode
200 Hz
SRxD
200 Hz
SCL
SCL
G(x) = x
DSAT/DST
24
12
0
1
2
3
4
5
6
+ x
10
+ x
8
+ x
5
shift register
25AD4D
shift register
26AB2B
26B2AD
2556CB
255B2B
256A9B
2669AB
+ x
DSAT
8-bit
4
8-bit
+ x
Sync word
HEX
HEX
HEX
HEX
HEX
HEX
3
HEX
30
+ x
0
DAA4D4
DAA934
DA52B2
D954D4
D94D52
DA9564
D69654
the logical inverse of the seven DSAT sequences.
The conversions DSAT/ DST and DST/DSAT must
be made without disturbing the phase of the DSAT.
There is also a special 24-bit digital mask for each of
the seven sequences. The mask defines the first bit
to be inverted when converting from DSAT to DST
or vice versa. Only when the bit in the mask is one
can the polarity be changed.
The generated bit sequence is written into shift
register 19
written to one of the 8-bit shift registers the other is
clocked out with a 200Hz clock. Each time the
contents of a shift register transmitted, the TXWRD
flag is set and an interrupt is generated. Note that
200 NRZ bits/second data has as many transitions
as 100 Manchester bits/second data.
DST
HEX
HEX
HEX
HEX
HEX
HEX
HEX
Data
40
GC8
HEX
8 bits at a time. While the next byte is
1C0FCD
BD780F
FF003E
0BBF82
0AE6F6
3FF118
8001FF
MASK
F12
HEX
HEX
HEX
HEX
HEX
HEX
HEX
DSAT/DST
DA9191A.000
July 31, 1997
24
Tx
15