PEB22554 SIEMENS [Siemens Semiconductor Group], PEB22554 Datasheet - Page 245

• Manufacturer Part Number: PEB22554
• Description: ICs for Communications
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Programmable Pulse Shaper and Line Build-Out
In long haul applications the transmit pulse masks are optionally generated according to
FCC68 and ANSI T1. 403. To reduce the crosstalk on the received signals the
QuadFALC offers the ability to place a transmit attenuator in the data path. Transmit
attenuation is selectable from 0 , -7.5, -15 or -22.5 dB (register LIM2.LBO2/1).
ANSI T1. 403 defines only 0 -15 dB.
The QuadFALC includes a programmable pulse shaper to satisfy the requirements of
ANSI T1. 102 , also various DS1, DSX-1 specifications are met. The amplitude of the
pulse shaper is individually programmable via the microprocessor interface to allow a
maximum of different pulse templates. The line length is selected by programming the
registers XPM2-0 as shown for typical values in the table below. The values with
transformer ratio: 1:2.4; cable: PULP 22AWG (100
register values are given in decimal.
Range in m
0 - 35
25 - 65
55 - 95
85 - 125
115 - 155
145 - 185
175 - 210
The transmitter requires an external step up transformer to drive the line.
Transmit Line Monitor
The transmit line monitor compares the transmit line current on XL1 and XL2 with an
on-chip transmit line current limiter. The monitor detects faults on the primary side of the
transformer indicated by a highly increased transmit line current (more than 120 mA for
at least 3 pulses) and protects the device from damage by setting the transmit line driver
XL1/2 automatically in a high impedance state. Two conditions will be detected by the
monitor: transmit line ones density (more than 31 consecutive zeros) indicated by
FRS1.XLO and transmit line high currrent indicated by FRS1.XLS. In both cases a
transmit line monitor status change interrupt will be provided.
Semiconductor Group
XP04-XP00
29
29
31
31
31
31
31
XP14-XP10
27
28
28
27
26
26
25
245
decimal
XP24-XP20
10
10
10
13
13
13
14
); serial resistors: 2
Functional Description T1 / J1
XP34-XP30
3
3
2
2
2
3
3
PEB 22554
. The XPM
09.98