User Guide

Parameter Values Description
Sign signed or
unsigned
The sign of the fixed-point data
Output data widths
Fraction 1 to 64 Number of fraction bits.
Width Derived Width of fixed-point data.
Sgn Derived The sign of the fixed-point data
Generate
enable port
On or off
Turn on for enable signal.
Scale factor
compensation
On or off For vector translate, a CORDIC specific constant that converges to 1.6467602... scales
the magnitude of the vector (x
2
+y
2
)
0.5
so that the value for the magnitude, M, is M =
K(x
2
+y
2
)
0.5
.
The format of the output depends on the input format. The largest output value occurs
when both the inputs are equal to the maximum representable input value, j.
In this context:
M = K(j
2
+j
2
)
0.5
= K(2j
2
)
0.5
= K2
0.5
(j
2
)
0.5
=K 2
0.5
j ~2.32j
Therefore, two extra bits left of the MSB of j are required to ensure M is representable.
If scale factor compensation is selected, M becomes: M = j
0.5
~ 1.41 j
One extra bit is sufficient for representing the range of M.
Scale factor compensation affects the total width of the output.
Table 5. Vector Rotate Parameters
Parameter Values Description
Input data widths
X,Y inputs
Fraction 1 to 64 Number of fraction bits.
Width Derived Width of fixed-point data.
Sign signed or
unsigned
The sign of the fixed-point data.
Angle input
Fraction Derived -
Width Derived -
Sign Derived -
Output data widths
Fraction 1 to 64 Number of fraction bits.
Width Derived Width of fixed-point data.
Sign Derived The sign of the fixed-point data
Generate
enable port
On or off
Turn on for enable signal.
Scale factor
compensation
Turn on to compensate the CORDIC-specific constant on the magnitude output. For
both signed and unsigned inputs, turning on decreases by 1 the weight of the
magnitude for x0 and y0. The outputs belong to the interval [-2
0.5
, +2
0.5
]K. Under
default settings, the output interval will therefore be [-2
0.5
K , +2
0.5
K] (with
continued...
1. ALTERA_CORDIC IP Core User Guide
683808 | 2017.05.08
ALTERA_CORDIC IP Core User Guide
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