Analog Devices ADRV9001 User Manual page 155

Reference Manual ADRV9001
TRANSMITTER/RECEIVER/OBSERVATION RECEIVER SIGNAL CHAIN CALIBRATIONS
Figure 143. Transmitter Initial Calibration System Configuration with Signal Generation and External Loopback Type 1
For TX_LO_LEAKAGE, another option is to use ELB2. Figure 144 shows the high level block diagram of system configurations for
TX_LO_LEAKAGE initial calibrations using ELB2 (note that the TX_LB_PD initial calibration using ELB2 is required for TX_LO_LEAKAGE).
Note that the TX_LO_LEAKGE initial calibration using ELB2 is a reserved function and the ADRV9001 does not support it.
Figure 144. Tx Initial Calibration System Configuration with Signal Generation and External Loopback Type 2
When the ELB2 feedback path is used, enable the power amplifier to make a full external loop between the transmitter outputs and the
observation channel inputs. The advantage of this calibration is to obtain a good estimate (gain/phase) of the external loop channel conditions
before operation. Figure 144 shows the device configuration. Note that the calibration signal might be transmitted through the antenna.
Although the power level of the calibration signal is set as low as possible, make sure it does not cause any problem when using this option.
It is important to choose a suitable attenuator between the power amplifier output and the observation channel input. This is to prevent the
transmitted data from saturating the observation channel input. The following paragraph summarizes the external system requirements.
External system requirements: Choose a suitable attenuator between the power amplifier output and the observation channel input to prevent
transmitted data from saturating the observation channel input. Switch off the LNA (or RF switch if no LNA is present externally) for the
loopback path to avoid receiving signals from the RF port.
System Considerations for Receiver Initial Calibrations
This section also has high level block diagrams that show the device configurations and external system requirements for receiver initial
calibrations. In all the diagrams, grayed-out lines and blocks are not active in the calibration. The blue blocks are related to calibrations.
Note that the ADRV9001 ARM performs each of the calibrations. It configures the ADRV9001 device per the diagrams, with respect to
enabling/disabling paths, and so on. No user input is required in this regard. However, it is important to meet the external system conditions,
such as terminating the receiver input properly for receiver initialization calibrations.
Among 13 different receiver initial calibrations, RX_HPADC_RC, RX_HPADC_FLASH, RX_HPADC_DAC (reserved not enabled), and
RX_LPADC calibrations are performed in the analog domain, and the corrections are applied to HP ADC or LP ADC (based on which one is
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