UG-1283
User Guide
Rev. A | Page 10 of 24
Transmit Load Override
For the gain and phase changes to take effect, a load transmit
override command must be given. To give this command, take
the following steps:
1.
Click the
MISC
tab (see Figure 13).
2.
In the
Over Ride
section, click
LDTX OVR
.
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78
8
-21
3
Figure 13. Load Transmit Override
RECEIVE STARTUP
The following procedures bypass the RAM, enable receive
subcircuits, set the device to SPI control, place the device in
receive mode, and set Receive Channel 1 to maximum gain and
45° phase.
Bypassing the RAM
To bypass the on-chip RAM and source the gain and phase data
from the configuration register, take the following steps:
1.
Click the
MISC
tab (see Figure 14).
2.
Select the
BEAM RAM BYPASS
check box and the
BIAS
RAM BYPASS
check box.
3.
Click
Write Value
.
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78
8-
21
4
Figure 14. Placing the Device in RAM Bypass Mode
Enabling Receive Channels
To enable the receive channels and associated circuits, take the
following steps:
1.
Click the
T/R Control
tab (see Figure 15).
2.
Select all check boxes in the
Rx Enable
section to enable all
four receive channels and the corresponding subcircuits.
3.
Click
Write Enable Values
.
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8-
2
15
Figure 15. Enabling Receive Channels
Setting Receive Bias Currents
To set the nominal bias currents for the receive VGAs, vector
modulators, and drivers, take the following steps:
1.
Click the
RX Registers
tab (see Figure 16).
2.
In the
Bias Current
section, set
RX VGA BIAS
to 2, set
RX VM BIAS
to 6, and set
LNA BIAS
to 8.
3.
Click
Write Bias Values
.
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88
-216
Figure 16. Setting Receive Bias Currents
