CMX644AD2 View Datasheet(PDF) - MX-COM Inc
Part Name
Description
MFG CO.
'CMX644AD2' PDF : 31 Pages View PDF
Bell 212A / V.22 Modem with Call Progress and DTMF
14
CMX644A Preliminary Information
4.3.2.7 TX PSK MODE Register ($E7)
(Bit 7)
TX- ENAB
(Bit 6)
SCRAMB UNLOCK
(Bit 5)
SCRAMB ENABLE
(Bit 4)
EQUAL ET1 and ET0
(Bits 3 and 2)
ENABLE
(Bit 1)
HI/LO BAND
(Bit 0)
Reserved for future use. This bit should be set to ‘0’.
This bit enables or powersaves the inverted output of the line driving amplifier
(TX-). When set to ‘1’ TX- is enabled; together with TX+ these outputs provide
sufficient complementary output to drive a line even at low VDD. When set to ‘0’
the TX- output is powersaved, reducing the total supply current for applications in
which a single-ended output is sufficient.
When this bit is set to ‘1’ the scrambler will check for sequences of 64 consecutive
ones at its output (caused by scrambler lockup) and once detected it will invert the
next input to the scrambler. When this bit is set to ‘0’ the lock-up prevention is
disabled.
When this bit is set to ‘1’ the Tx data is passed through the scrambler. When it is
set to ‘0’ the scrambler is bypassed.
These 2 bits control the level of equalization applied to the transmitted signal
according to Table 17.
See Figure 8 and Figure 9 for the typical equalizer responses. The equalizer is
automatically powersaved when both ET1 and ET0 are set to '0'.
When this bit is set to ‘1’ the internal output of the PSK modulator is enabled.
When it is set to ‘0’ the internal output of the PSK modulator is set to VBIAS.
Associated flags are only set when this bit is ‘1’.
This bit determines whether the transmitted PSK signal should occupy the low
channel (900Hz - 1500Hz) or the high channel (2100Hz - 2700Hz). When the bit is
set to ‘0’ the low channel is selected. When it is set to ‘1’ the high channel is
selected.
Table 16: TX PSK MODE Register ($E7)
ET1 (Bit 3)
0
0
1
1
ET0 (Bit 2)
0
1
0
1
Transmitter Equalization
no equalization
Low
Medium
High
Table 17: EQUAL ET1 and ET0
2000 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. # 20480197.006
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
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