User`s guide

3 Working with Signals
3-20
Because the Frame-based mode parameter in the Upsample blocks is set to
Maintain input frame size rather than Maintain input frame rate, each
Upsample block changes the frame rate. Therefore, each frame-based signal in
the model is assigned a different color.
If the Upsample blocks are instead set to
Maintain input frame rate, then
every signal in the model shares the same frame rate, and as a result, every
signal is coded with the same color.
For more information about sample time color coding, see “Sample Time
Colors” in the Simulink documentation.
Converting Sample Rates and Frame Rates
In a DSP Blockset model, there are two types of periods that you will commonly
be concerned with: sample periods and frame periods. The input and output
sample periods of a block (T
si
and T
so
, respectively) are related to the input and
output frame periods (T
fi
and T
fo
, respectively) by
where M
i
and M
o
are the input and output frame sizes, respectively.
The buffering and rate-conversion capabilities of the DSP Blockset generally
allow you to independently vary any two of the three parameters (T
so
,T
fo
,M
o
).
In most cases, the sample period and the frame size are the two parameters of
primary interest; the frame period is simply a consequence of your choices for
the other two.
There are two common types of operations that impact the frame and sample
rates of a signal:
T
si
T
fi
M
i
⁄=
T
so
T
fo
M
o
⁄=