PEB2085 SIEMENS [Siemens Semiconductor Group], PEB2085 Datasheet - Page 89

• Manufacturer Part Number: PEB2085
• Description: ISDN SubscribernAccess Controller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

2.5.4.1
In order to additionally reduce the bit error rate in severe conditions, the ISAC-S performs
oversampling of the received signal and uses majority decision logic. (Note: this feature is
implemented in TE and LT-T modes only).
As illustrated in figure 50, each received bit is sampled 29 times at 7.68-MHz clock intervals
inside the estimated bit window. The samples obtained are compared against a threshold
VTR1 or VTR2 (see section: Adaptive Receiver Characteristics).
If at least 16 samples have an amplitude exceeding the selected threshold, a logical "0" is
considered to be detected, otherwise a logical "1" (no signal) is considered detected.
Figure 50
S/T Receive Signal Oversampling
Semiconductor Group
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TR1
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Receive Signal Oversampling
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TR2
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Derived 192-kHz Receive Bit Period
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Functional Description
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ITD02361
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