L2330
DEVICES INCORPORATED
Coordinate Transformer
ACC
1-0
— Accumulator Control
ACC
1-0
is the 2-bit accumulator
control that determines four modes as
shown in Table 2. Changing of the
internal phase Accumulator structure
is very useful when RTP is LOW
allowing for waveform synthesis and
modulation. ACC
1-0
set to ‘00’ is most
commonly used when RTP is HIGH
unless performing backward mapping
from Cartesian to Polar coordinates.
TCXY — Data Input/Output Format
Select
When TCXY is HIGH, two’s comple-
ment format is selected. When TCXY
is LOW, sign-and-magnitude format is
selected.
Table 1. ‘M’ is the Modulation
Register and ‘C’ is the Carrier Register
as shown in the Functional Block
Diagram.
RTP — Rectangular-to-Polar
When RTP is HIGH, Rectangular-to-
Polar conversion mode is selected.
When RTP is LOW, Polar-to-Rectan-
gular conversion mode is selected.
F
IGURE
1
A
.
I
NPUT
F
ORMATS
XRIN
YPIN
(RTP = 0)
Fract. Unsigned Mag./Two's Comp.
31 30 29
*±2
0
2
–1
2
–2
2 1 0
2
–29
2
–30
2
–31
Integer Unsigned Magnitude
15 14 13
2
15
2
14
2
13
2 1 0
2
2
2
1
2
0
Integer Signed Magnitude (RTP = 1, TCXY = 0)
15 14 13
NS 2
14
2
13
2 1 0
2
2
2
1
2
0
31 30 29
NS 2
14
2
13
18 17 16
2
2
2
1
2
0
Integer Two's Complement (RTP = 1, TCXY = 1)
15 14 13
–2
15
2
14
2
13
2 1 0
2
2
2
1
2
0
31 30 29
–2
15
2
14
2
13
18 17 16
2
2
2
1
2
0
(RTP = 0)
Fractional Unsigned Magnitude
Fract. Unsigned Mag./Two's Comp.
15 14 13
2
0
2
–1
2
–2
2 1 0
2
–13
2
–14
2
–15
31 30 29
*±2
0
2
–1
2
–2
2 1 0
2
–29
2
–30
2
–31
Fractional Signed Magnitude (RTP = 1, TCXY = 0)
15 14 13
NS 2
–1
2
–2
2 1 0
2
–13
2
–14
2
–15
31 30 29
NS 2
–1
2
–2
18 17 16
2
–13
2
–14
2
–15
Fractional Two's Complement (RTP = 1, TCXY = 1)
15 14 13
–2
0
2
–1
2
–2
2 1 0
2
–13
2
–14
2
–15
31 30 29
–2
0
2
–1
2
–2
18 17 16
2
–13
2
–14
2
–15
*±2
0
denotes two's complement sign or highest magnitude bit. Since phase angles are modulo 2π
and phase accumulator is modulo 2
32
, this bit may be regarded as ±π.
NS denotes negative sign. (i.e. '1' negates the number)
Special Arithmetic Functions
3
09/27/2001–LDS.2330-E
LOGIC [ LOGIC DEVICES INCORPORATED ]
