DS26334DK Maxim Integrated Products, DS26334DK Datasheet - Page 36

• Manufacturer Part Number: DS26334DK
• Description: KIT DESIGN FOR DS26334
• Manufacturer: Maxim Integrated Products

Specifications of DS26334DK

• Main Purpose: Telecom, Line Interface Units (LIUs)
• Utilized Ic / Part: DS26334
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

DS26334 3.3V, 16-Channel, E1/T1/J1 Short/Long-Haul Line Interface Unit
5.9.3 Receive Pattern Detection
The Receive BERT receives only the payload data and synchronizes the receive pattern generator to the incoming
pattern. The receive pattern generator is a 32-bit shift register that shifts data from the least significant bit (LSB) or
bit 1 to the most significant bit (MSB) or bit 32. The input to bit 1 is the feedback. For a PRBS pattern (generating
n
y
polynomial x
+ x
+ 1), the feedback is an XOR of bit n and bit y. For a repetitive pattern (length n), the feedback is
bit n. The values for n and y are individually programmable (1 to 32). The output of the receive pattern generator is
the feedback. If QRSS is enabled, the feedback is an XOR of bits 17 and 20, and the output will be forced to one if
the next 14 bits are all zeros. QRSS is programmable (on or off). For PRBS and QRSS patterns, the feedback will
be forced to one if bits 1 through 31 are all zeros. Depending on the type of pattern programmed, pattern detection
performs either PRBS synchronization or repetitive pattern synchronization.
5.9.3.1
Receive PRBS Synchronization
PRBS synchronization synchronizes the receive pattern generator to the incoming PRBS or QRSS pattern. The
receive pattern generator is synchronized by loading 32 data stream bits into the receive pattern generator, and
then checking the next 32 data stream bits. Synchronization is achieved if all 32 bits match the incoming pattern. If
at least six incoming bits in the current 64-bit window do not match the receive pattern generator, automatic pattern
re-synchronization is initiated. Automatic pattern re-synchronization can be disabled.
See
Figure 5-13
for the PRBS synchronization diagram.
Figure 5-13. PRBS Synchronization State Diagram
Sync
1 bit error
Verify
Load
32 bits loaded
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