comtech
aha
corporation
PRODUCT BRIEF
AHA G709D-40 FEC Core
40 GB/S ITU G.709
REED-SOLOMON DECODER
The G709D-40 core implements the 16 block
interleaved RS(255,239) code specified by in
Annex A of the ITU G.709 standard.
The G709D-40 core is specifically designed to
efficiently perform the Reed-Solomon decoding
function specified by the standard. The core
requires no configuration, no initialization, and no
re-synchronization procedure or includes any
unnecessary features that would add area, power or
complexity to your design.
A G709E Reed-Solomon encoder core is also
available from AHA.
FEATURES
• ITU G.709 compatible Reed-Solomon core
• Input and output data streams are block-
interleaved for seamless connection in G.709
system
• 40 Gbits/sec operation in 0.13µ CMOS process
• 220 Kgates in 0.13µ using a typical standard cell
library
• One-edge, one-clock fully synchronous design
without multi-cycle paths
• Separate FIFO for increased flexibility and
simplified IC floor planning
• Complete error reporting for Bit Error Rate
calculation and feedback into threshold detection
circuits
Figure 1:
AHA G709D-40 FEC
correct_to_zero[10:0]
reset
clk
start
received_data[127:0]
correct_to_one[10:0]
status_valid
AHA G709D-40 FEC
decode_complete
uncorrectable[15:0]
decoded_data[127:0]
FIFO – 64 Kbit
(available from AHA)
comtech
aha
corporation
fifo_data[127:0]
comtech
aha
corporation
INPUT SIGNALS
clk
- 332 MHz core clock. All inputs are registered
on the rising edge.
reset
- Synchronous reset.
received_data[127:0]
- Received data bus. Data
bus is valid every clock and is registered on the
rising edge of
clk.
The data frame is restarted
whenever
start
is active. The core accepts 8-
bytes per transfers
start
- Signal is active to when the first 8 bytes of
the G.709 frame in on the
received_data
bus.
Must be inactive on all other data transfers in
the frame. Maybe asserted at anytime of the
data frame needs to be reset to the first transfer.
fifo_data[127:0]
- FIFO data. Delay version of the
received_data
data stream. The bus is
registered on the rising edge of
clk.
DELIVERABLES
• G.709D-40 FEC core (VHDL)
• Timing constraints (DesignCompiler and Ambit
format)
• Test bench and verification vectors (VHDL)
• Single use license to AHA’s Reed-Solomon
patents
PATENTS
Design uses one or more of the following US
Patents: 5,170,399; 5,099,482; 4,873,688;
5,396,502
ABOUT AHA
Comtech AHA Corporation (AHA) develops
and markets superior integrated circuits, boards,
and intellectual property core technology for
communications systems architects worldwide.
AHA has been setting the standard in Forward Error
Correction and Lossless Data Compression
technology for many years and provides flexible,
cost-effective solutions for today’s growing
bandwidth and reliability challenges. Comtech
AHA Corporation is a wholly owned subsidiary of
Comtech Telecommuncations Corp. (NASDAQ:
CMTL). For more information, visit www.aha.com.
OUTPUT SIGNALS
decode_complete
- Decoding complete. Active
when the first 8-byte transfer of the G.709
frame is on the
decode_data
data bus and
inactive on all subsequent transfers.
decoded_data[127:0]
- Decoded data. The first 8-
bytes of the corrected G.709 frame are valid
when
decode_complete
is active and the
remainder of the frame is available over the
subsequent 509 clocks. The data is driven from
the rising edge of
clk.
status_valid
- Status valid signal. Active for a
single
clk
following the completion of the
frame to indicate when the
uncorrectable,
correct-to-zero,
and
correct_to_one
signals
are valid.
uncorrectable[15:0]
- Uncorrectable block flags.
Each bit of the signal corresponds to one of the
16 Reed-Solomon blocks in the G.709 frame.
Valid when
status_valid
is active.
correct_to_zero[10:0]
- Number of bits corrected
from ‘1’ to ‘0’ in the just completed G.709
frame. Signal is valid when
status_valid
is
active.
correct_to_one[10:0]
- Number of bits corrected
from ‘0’ to ‘1’ in the just completed G.709
frame. Signal is valid when
status_valid
is
active.
comtech
aha
corporation
A subsidiary of Comtech Telecommunications Corporation
1126 Alturas Drive
Moscow, ID 83843-8331
tel: 208.892.5600
fax: 208.892.5601
e-mail: sales@aha.com
www.aha.com
PBG709D40_0203
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2005 Comtech AHA Corp.
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