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AR# 23250

8.1.01 System Generator for DSP - Why are my Gateway In blocks behaving differently between System Generator for DSP 7.1, 8.1, and 8.1.01?

Description

Why are my Gateway In blocks behaving differently between System Generator for DSP 7.1, 8.1 and 8.1.01?

Solution

This is a result of a change in the default behavior of the System Generator for DSP Gateway In blocks.

There are two settings for the Gateway In blocks:

Quantization: Which can be set to Truncate or Round (unbiased: +/- Inf)

Overflow: Which can be set to Wrap, Saturate or Flag as error

In System Generator for DSP 7.1 and prior, the default behavior was for the Gateway In block was Round (unbiased: +/- Inf) and Wrap.

In System Generator for DSP 8.1, the options were removed due to some significant backend changes, and the only behavior for the Gateway In block was Truncate and Wrap.

In System Generator for DSP 8.1.01 and beyond, we were able to bring back all of the options, but the default behavior was changed to Round (unbiased: +/- Inf) and Saturate.

Beware that this change in the behavior of the Gateway In block is not flagged and might cause differences in your simulation results. Please check the setting of the Gateway In blocks to make sure they behave as you would expect.

AR# 23250
Date Created 09/04/2007
Last Updated 12/15/2012
Status Active
Type General Article