PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 66

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

Semiconductor Group
output buffers. The shape of a DAC-output signal is shown below, the peak amplitude is
normalized to one. This signal is fed to an RC-lowpass of first order with a corner
frequency of 1 MHz
Figure 20
The duration of each pulse is 24 steps, with T0 t = 0.78 s per step. On the other hand,
the pulse rate is 80-kHz or one pulse per 16 steps. Thus, the subsequent pulses are
overlapping for a duration of 8 steps.
Line Driver
The Line Driver is optimized for
– High output swing
– High linearity
– Low quiescent current to minimize power consumption
The output jitter produced by the transmitter (with jitter-free input signals) is below 0.02
UIpp (Unit interval = 12.5 s, peak-peak) measured with a high-pass filter of 30-Hz cutoff
frequency. Without the filter the cutoff jitter is below 0.1 UIpp.
Analog Loop-Back Function
An internal analog loop-back function can be activated (see "Analog Loop-Back (No.
1/No. 3)", page 187). This loop-back is closed near the U-interface. If it is active all
signals received on AIN / BIN will neither be evaluated nor recognized.
0.75
0.25
1.0
0.5
1 2 3 4 5 6 7 8 9
DAC-Output for a Single Pulse
50%.
T0 = 0.78
66
s
15
18
Functional Description
23
Data Sheet 01.99
x T0
PEB 2091
PEF 2091