HDM8513 datasheet(51/67 Pages) HYNIX

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Control Parameters for Viterbi and RS Decoders

Bit 0. Parallel or Serial Output

Controls the transport stream output of the 8513A to serial or parallel

mode.

“0” (default) means the 8513A MPEG output is parallel.

“1” means the 8513A MPEG output is serial. The LSB of the data

bus(data[0] - pin 98) is used as the serial output pin.

Bit 1. MPEG2 Data

“0” (default) means the incoming data is MPEG2 decoded. In this mode

a sync byte is expected every 188 bytes.

“1” means non-MPEG2 data. The Viterbi decoder doesn’t check the

existence of the sync byte.

Bit [4:2]. Depuncturing Rate

It defines the depuncturing rate of the Viterbi decoder. When

vb_autocode is disabled, the depuncturing rate is set to this value.

0 --- 1/2

1 --- 2/3

2 --- 3/4

3 --- 5/6

4 --- 7/8

5 --- 6/7

Bit 5. Viterbi Auto Decoding Mode

When this bit is set to 1, the Viterbi decoder automatically finds the

correct code rate of the incoming signal. When this bit is set to 0, the

code rate is set to the user-defined value at bit[4:2]. The default is 0.

Bit 6. DSS Mode

When this bit is set to 0, this device operates as DVB mode. When

this bit is set to 1, this device operates as DSS mode. In that case, the

roll-off factor of the Nyquist filter is set to 0.2. The default is 0 (DVB).

Bit 7. BPSK Mode

When this bit is set to 0, the demodulator assumes the incoming data

is QPSK-modulated. When this bit is set to 1, the demodulator

assumes the incoming data is BPSK-modulated.

Rate 1/2 Threshold Select

This seven bit parameter defines the threshold used in the Viterbi

decoder node synchronization process. For rate 1/2, the nominal value

is 30 (1EH).

HDM8513 датащи(PDF) 51 Page - Hynix Semiconductor