Xilinx V2.1 - Manual (Page 92)

92 Xilinx Development System
Xilinx System Generator v2.1 Reference Guide
Scale
The Xilinx Scale block scales its input by a power of two. The power
can be either positive or negative. The block has one input and one
output. The scale operation has the effect of moving the binary point
without changing the bits in the container.
Block Parameters Dialog Box
The block parameters dialog box can be invoked by double-clicking the icon in your
Simulink model.
Figure 3-63: Scale block parameters dialog box
The only parameter that is specific to the Scale block is Scale Factor . It can be a
positive or negative integer. The output of the block is i2
k
, where i is the input value
and k is the scale factor. The effect of scaling is to move the binary point, which in
hardware has no cost (a shift, on the other hand, may add logic).
The other parameters used by this block are explained in the Common Parameters
section of the previous chapter.
The Scale block does not use a Xilinx LogiCORE.
Shift
The Xilinx Shift block performs a left or right shift on the input signal.
The result will have the same fixed point container as that of the input.