UG-1828 Preliminary Technical Data
Rev. PrC | Page 310 of 338
Receiver Gain Control
The receiver Gain Control tab (Figure 295) allows user to configure per channel, receiver gain control mode. Configuration selected in
that tab is then applied to the ADRV9001 during initialization. During runtime user can change interface gain as well as if manual mode
is enabled Rx gain.
Interface Gain provides ability to select MSBs or LSBs 16 bits from the data bus. This operation can be interpreted as a signal gain. In
TDD operation, the user has the option to update the interface gain Now or in the Next Frame. For more details, see the
Receiver Gain
Control section.
By selecting the Manual radio button in Gain Control Mode, the user can select initial gain value. Receiver gain can be changed
dynamically during receiver capture operation.
By selecting the Automatic radio button in Gain Control Mode, the user can configure basic ADRV9001 internal AGC parameters. The
AGC becomes operational and automatically adjusts the receiver gain level when the ADRV9001 starts to receive data in the Receive tab.
See the Receiver Gain Control section for more information about AGC operation.
The user also has the ability to select Correction or Compensation for Gain Compensation operation.
• Compensation: the process of compensating for the analog attenuation in the device (prior to the ADC) with a corresponding
amount of digital gain before the digital signal is sent to the user. Gain compensation uses the digital gain to effectively undo analog
gain so from receiver data recipient signal stays constant. The digital gain is effectively compensating for the analog attenuation.
• Correction: the process of correction uses digital gain to make the gain steps more accurate. This is to ensure receiver gain steps are
accurate.
Filters
ADRV9001 evaluation software allows users to specify their own custom programmable filter for the receiver. This filter is up to 128 taps. The
custom filter must be in the format of csv or txt file and coefficients must be 24-bit signed integers with no carriage returns. An example
filter .txt file is provided in the SDK . There is also the option to bypass this filter entirely.
An important thing to note when programming the part is the calibrations will use the carrier BW set by the user. If the BW of the loaded
filter is smaller than the BW of the carrier then the calibration will fail. This is due to the signal being attenuated by the filter. Setting a
small filter is best done after the part has been initialized and the calibrations have been run.
GPIO Configuration
Receiver Gain Control
DGPIOs on the evaluation board from DGPIO_0 to DGPIO_11 can be used for feedback signals as well as setting gain index for receiver
gain control (see Figure 295).
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