ISL5239 Datasheet, PDF (25/31 Pages) Intersil Corporation – Pre-Distortion Linearizer

BIT
15:14
13:12
FUNCTION
Reserved
Magnitude Function
Select
11:0 Address Offset
BIT
15:13
12:0
FUNCTION
Reserved
Address Scale
BIT
15:14
13
FUNCTION
Reserved
Active LUT
12
11:10
9:0
LUT Address Auto
Increment
Reserved
LUT Address
BIT
15:14
13:0
FUNCTION
Reserved
LUT Data Delta Q
BIT
15:14
13:0
FUNCTION
Reserved
LUT Data Delta I
BIT
FUNCTION
15:0 LUT Data Q
ISL5239
TABLE 20. MAGNITUDE FUNCTION CONTROL
TYPE: PRE-DISTORTER, ADDRESS: 0x11
DESCRIPTION
Not used
Selects the magnitude calculation function as:
00 - Log. Log base 2 of magnitude squared computed as log2(I² + Q²)
01 - Linear. Linear magnitude computed as sqrt (I² + Q²)
10 - Power. Magnitude squared computed as (I² + Q²)
Linear offset of magnitude function when calculating LUT address (e.g. power backoff) Selectable from
(-1024...1024) in increments of 2^-1. Note: Setting the LSB of this value permits rounding of the resulting
address. Clearing the LSB causes truncation. (0xFFFFF --> 0x00000 maps to -1024 to 0, and 0x00001 -
-> 0x7FFFF maps to 0.5 to 1023.5).
TABLE 21. I - MAGNITUDE FUNCTION SCALE FACTOR
TYPE: PRE-DISTORTER, ADDRESS: 0x12
DESCRIPTION
Not Used.
Linear scale of magnitude function when calculating LUT address (e.g. db/LSB) Selectable from (0.(64-
increment)), in increments of 2^-7.
TABLE 22. Q - LOOK-UP TABLE CONTROL
TYPE: PRE-DISTORTER, ADDRESS: 0x13
DESCRIPTION
Not Used.
Selects which ping pong LUT is currently in use. The opposite LUT shall be accessible through the
processor interface.
0 - Use LUT 0, access LUT 1.
1 - Use LUT 1, access LUT 0.
Set high to automatically increment LUT address after any access operation (read/write). Default is low,
not auto increment.
Not used.
Address for index into LUT. Default = 0, pointer to next LUT location.
TABLE 23. LOOK-UP TABLE DELTA IMAGINARY DATA
TYPE: PRE-DISTORTER, ADDRESS: 0x14
DESCRIPTION
Not used.
Delta imaginary Data written to or read back from LUT. Delta Q controls memory effect. Selectable as (-
0.125...(0.125-increment)) in increments of 2^-16. Default = 0.
TABLE 24. LOOK-UP TABLE DELTA REAL DATA
TYPE: PRE-DISTORTER, ADDRESS: 0x15
DESCRIPTION
Not used.
Delta real data written to or read back from LUT. Delta I controls memory effect. Selectable as (-
0.125...(0.125-increment)) in increments of 2^-16. Default = 0.
TABLE 25. LOOK-UP TABLE IMAGINARY DATA
TYPE: PRE-DISTORTER, ADDRESS: 0x16
DESCRIPTION
Imaginary distortion data written to or read back from LUT. Selectable as (-0.5...(0.5-increment)) in
increments of 2^-16. Default = 0.
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