Datasheet

Data Sheet AD9958
Rev. B | Page 23 of 44
Eight-Level Modulation—No RU/RD
The modulation level bits (FR1[9:8]) are set to 10 (eight-level).
The AFP select bits (CFR[23:22]) are set to a nonzero value.
The RU/RD bits (FR1[11:10]) and the linear sweep enable bit
(CFR[14]) are disabled. Note that the AFP select bits of the
other channel not being used must be set to 00. Table 11 shows
the assignment of profile pins and channels.
For the condition in Table 11, the choice of channel word registers
is based on the 3-bit value presented to Profile Pins [P0:P2]. For
example, if PPC = X10 and [P0:P2] = 111, the contents of the
Channel Word 7 register of Channel 0 are presented to the output
Channel 0.
16-Level Modulation—No RU/RD
The modulation level bits (FR1[9:8]) are set to 11 (16-level).
The AFP select bits (CFR[23:22]) are set to the desired modulation
type. The RU/RD bits (FR1[11:10]) and the linear sweep enable
bit (CFR[14]) are disabled. The AFP select bits of the other channel
not being used must be set to 00. Table 12 displays how the profile
pins and channels are assigned.
For the conditions in Table 12, the profile register chosen is
based on the 4-bit value presented to Profile Pins [P0:P3]. For
example, if PPC = X11 and [P0:P3] = 1110, the contents of the
Channel Word 14 register of Channel 1 is presented to the
output of Channel 1.
Two-Level Modulation Using Profile Pins for RU/RD
When the RU/RD bits = 01, Profile Pin P2 and Profile Pin P3
are available for RU/RD. Note that only a modulation level of
two is available in this mode. See Table 13 for available pin
assignments.
Eight-Level Modulation Using a Profile Pin for RU/RD
When the RU/RD bits = 10, Profile Pin P3 is available for
RU/RD. Note that only a modulation level of eight is available
in this mode. See Table 14 for available pin assignments.
Table 11. Profile Pin and Channel Assignments for Eight-Level Modulation (No RU/RD)
Profile Pin Config. (PPC)
(FR1[14:12]) P0 P1 P2 P3 Description
X10 CH0 CH0 CH0 X Eight-level modulation on CH0, no RU/RD
X11 CH1 CH1 CH1 X Eight-level modulation on CH1, no RU/RD
Table 12. Profile Pin and Channel Assignments for 16-Level Modulation (No RU/RD)
Profile Pin Config. (PPC)
(FR1[14:12]) P0 P1 P2 P3 Description
X10 CH0 CH0 CH0 CH0 16-level modulation on CH0, no RU/RD
X11 CH1 CH1 CH1 CH1 16-level modulation on CH1, no RU/RD
Table 13. Profile Pin and Channel Assignments for Two-Level Modulation (RU/RD Enabled)
Profile Pin Config. (PPC)
(FR1[14:12]) P0 P1 P2 P3 Description
101 CH0 CH1 CH0 RU/RD CH1 RU/RD Two-level modulation on CH0 and CH1 with RU/RD
Table 14. Profile Pin and Channel Assignments for Eight-Level Modulation (RU/RD Enabled)
Profile Pin Config. (PPC)
(FR1[14:12]) P0 P1 P2 P3 Description
X10 CH0 CH0 CH0 CH0 RU/RD Eight-level modulation on CH0 with RU/RD
X11 CH1 CH1 CH1 CH1 RU/RD Eight-level modulation on CH1 with RU/RD