563489578934

TABLE 5–6
V.32 MODEM STANDARD
Item
Signal Constellation
372
Data Serial binary, Asynchronous or synchronous Option 2: 32 QAM or QPSK
Full duplex over two-wire line a
y
Carrier frequency
Option 1
DATA rate
Modulation
Transmit a : 1,800 Hz
Receive a : 1,800 Hz
9,600 bs for high SNR
4,800 bs for low SNR
32 QAM, 2400 baud, for high SNR using
trellis-coded modulation (see Fig. 1–9,
where n = 3 and m - k = 2) with 4 data
bits plus 1 coding bit per symbol
QPSK, 2,400 baud (states A, B, C, D) for
low SNR
4
11111 11000
D
01000 00101 01010
2
10010 10101 10011 10100
C
00000 01111 00010 01101 00011
4 11001 2 11110 11010 2 11101 4
A
00111 01001 00110 01011 00100
2
10000 10111 10001 10110
B
01110 00001 01100
4
11100 11011
x
Option 2
. DATA rate 9,600 bs for high SNR
Modulation
4,800 bs for low SNR
16 QAM, 2,400 baud, for high SNR
QPSK, 2,400 baud (states A, B, C, D) for
low SNR
Option 2: 16 QAM or QPSK
y
D
1011 1001 1110 1111
2
C
1010 1000 1100 1101
2
2
A
0001 0000 0100 0110
2
B
0011 0010 0101 0111
x
a A two-wire to four-wire hybrid is used in this modem to obtain the transmit and receive lines.