CS3410 Amphion Semiconductor Ltd., CS3410 Datasheet - Page 5

• Manufacturer Part Number: CS3410
• Description: High Speed Viterbi/TCM Decoder
• Manufacturer: Amphion Semiconductor Ltd.

Differential Decoder
Differential Decoder block is required to eliminate ±180°
phase ambiguities introduced by QPSK demodulation
(assumes that input data to convolutional encoder has been
differentially encoded). A bypass mode is also available.
Sync Monitor
Synchronisation monitor indicates the phase synchronisation
status/error with respect to the input data vectors.
BER Monitor
Channel bit error rate estimation unit
µP Interface
Microprocessor interface facilitates the decoder setup/control
and status monitoring.
TCM MODE
Input Data Format
In TCM mode, input I/Q vectors must be provided in a signed
magnitude form.
TCM BM Unit
This unit provides the branch metric calculator and rotation
logic for TCM decoder. It computes branch metrics using 8-bit
signed magnitude formatted I/Q vectors. Branch metric
Figure 4: TCM Decoder Block Diagram
Status/Control
Sync Control
µ
P Interface
CLK
Q
I
Sync Control
µ
TCM BM
Rotation
P Interface
Unit
BM
+
Decoder
Viterbi
rotation is supported for 'out-of-sync' states thus eliminating
any ±
may arise. A sector number which describes a receive point in
PSK space is generated for the PARD unit.
Sync Control
Provides
synchronization of input I/Q vectors through the rotation of
branch metrics in the TCM BM unit.
Viterbi Decoder Core
This block is a 64-state Viterbi core and associated control and
memory units.
Differential Decoder/PARD
Differential Decoder and Phase Ambiguity Resolution
Decoder (PARD) are used to obtain TCM decoded bits
(includes a PARD pre-processor). A differential bypass mode
is also available.
Sync Monitor
Synchronization monitor indicates the phase synchronization
status/error with respect to the input data vectors.
µ
Microprocessor interface facilitates the decoder setup/control
and status monitoring.
P Interface
π
/4 (8-PSK) and ±
Differential
a
Decoder/
Monitor
Sync
PARD
method
π
/8 (16-PSK) phase ambiguities that
to
Sync Status
TCMDATA
control/adjust
the
phase
5
TM