MA1916 Datasheet, PDF (3/11 Pages) Dynex Semiconductor – Radiation Hard Reed-Solomon & Convolution Encoder

MA1916
CONVOLUTION ENCODER
The convolution encoder generates 2 serial bits of output
data for each bit it reads in. The coding operates cyclically over
a length of 7 bits. It increases the bandwidth of the signal but
establishes a correlation between succesive bits in the output
signal.
The convolution encoder operates continuously using
CE_CLK to read data in on CE_IN and to write the encoded
data to CE_OUT.
If required the output of the Reed-Solomon encoder can be
fed directly into the convolution encoder by connecting
RSE_OUT to CE_ IN and CLKS to CE_CLK.
TEST GENERATOR
The MA1916 contains its own built-in test pattern
generator, this can be connected to the RS encoder for in
service testing. The test generator supplies test patterns and
the SMC signal according to the inputs on T0-2 (see Table 2)
and the interleave depth selected using SEL_A and SEL_B.
Figure 3 shows the necessary connections for feeding test
patterns through both the RS and the convolution encoder.
Figure 3: Test Configuration
T2 T1 T0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
Other
Test
N/A
1
2
3
4
N/A
I = 5 (1115 bytes)
Interleave Depth
I = 4 (892 bytes)
(1, 2, 3, 4, 5) x 223
(0) x 222 x 5, (0) x 4, (7B)
(0) x 222 x 5, (7B, AF, 99, FA, B7)
(0) x 221 x 5, (7B) x 5, (47) x 5
(1, 2, 3, 4) x 223
(0) x 222 x 4, (0) x 3, (7B)
(0) x 222 x4, (7B, AF, 99, FA)
(0) x 221 x 4, (7B) x 4, (47) x 4
Table 2: Test Pattern on MSG_OUT Defined by T0-2
I = 1 (223 bytes)
0
(1) x 223
(0) x 222, 7B
(0) x 222, 7B
(0) x 222, 7B
PIN DESCRIPTION
V_DD and GND (Power and Ground)
The MA1916 uses a single power supply of 5V ±10%.
CLK (Clock)
This input supplies a clock signal to the RS encoder and
the Test generator. It requires a signal with a nominal 50%
duty cycle running at twice the input data rate for the RS
encoder. The rising edge of CLK is used to generate the
internal CLKS signal which clocks data through the RS
encoder.
n_RST (Reset)
This active low signal is a reset supplied to the RS encoder,
the test generator and the convolution encoder. It should be
noted that the reset does not clear the check sum in the RS
encoder and a complete dummy data packet should be run
through before valid data is sent.
SEL_A and SEL_B (Interleave Depth Select)
These inputs define the interleave depth of a message
passing through the RS encoder They also specify the
message length to be produced by the test generator (see
Table 1). The inputs are connected to internal pulldown
resistors.
T_0-2 (Test Pattern Select)
These inputs select the pattern to be produced by the test
generator (see Table 2). Each input is connected to an internal
pull-down resistor.
T₃ (Production Test Input)
This input is used for production testing only It has an
internal pull-down resistor and should be left unconnected .
MSG_OUT (Test Message Output)
This output pin carries the test patterns defined by the
inputs To-2 and produced by the test generator. This signal
can be connected directly to MSG for testing purposes.
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