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AR# 22641

LogiCORE Viterbi Decoder - How do I calculate the data rates for the LogiCORE Viterbi Decoder operating in various configurations?

Description

How do I calculate the data rates for the LogiCORE Viterbi decoder v5.0?

Solution

Parallel Non-punctured Mode and External Punctured Mode

Data rate = clock rate

If the clock is 150 MHz, the symbol rate = 150 Mbps.

Parallel Internal Punctured Mode

Data rate = clock rate * punctured rate

If the clock is 150 MHz and the puncture rate is 3/4, the symbol rate = 150 MHz (clock rate) *3/4 (puncture rate) = 112.5 Mbps.

These are the rates because the internally punctured decoder has one single data input bus (one channel) as shown in figure 10 of the Viterbi v5.0 data sheet.

Serial Non-punctured Mode and External Punctured Mode

Data rate for the serial non-punctured case is as follows:

Data rate = (clock rate / (soft bit + output rate + 6))

If the clock is 110 MHz, the soft width = 3 and the output rate is 2.

Symbol rate = 110 MHz(clock rate) /3(soft width)+2 (output rate)+6) = 110/ 11 = 11 Mbps

Serial Internal Punctured Mode

Data rate for the serial punctured case is as follows:

Data rate = (clock rate / (soft bit + output rate + 6)) * punctured rate

If the clock is 110 MHz, the soft width = 3 and the output rate is 2 and the puncture rate is 7/8 symbol rate is 11*7/8 = 9.625 Mbps.

Please see (Xilinx Answer 29448) for a detailed list of LogiCORE Viterbi Decoder Release Notes and Known Issues.

AR# 22641
Date Created 09/04/2007
Last Updated 12/15/2012
Status Active
Type General Article