Analog Devices ADRV9005 Reference Manual page 166

Reference Manual
TRANSMITTER/RECEIVER/OBSERVATION RECEIVER SIGNAL CHAIN CALIBRATIONS
Among nine transmitter initial calibrations, except for TX_DAC, all other eight calibrations require to insert the tone/wideband signal into the
transmitter datapath from an internal signal generator. Therefore, the internal microprocessor disables the data port to avoid interference. Some
calibration algorithms, such as TX_LB_PD, TX_QEC, TX_LOL, TX_DCC, and TX_ATTEN_DELAY further require the use of the observation
datapath through ILB to receive the transmitted signal so that a joint analysis is performed by observing the relationship between the
transmitted and received signals.
Transmitter Initial Calibrations Utilizing Internal Signal Generation Without Loopback
Figure 152 shows a high level block diagram of the system configurations for transmitter initial calibrations that require inserting signals into the
transmitter datapath without using a loopback path.
Figure 152. Transmitter Initial Calibration System Configuration with Signal Generation Without Loop Back
Figure 152 shows how an internal signal generator inserts calibration signals (red) into the transmitter datapath. The data port is disabled
during initial calibrations to avoid interference. TX_PATH_DELAY is performed in the digital domain, whereas TX_BBAF and TX_BBAF_GD
are performed in the analog domain. All use the signal generator to insert tones for calibration. During all these calibrations, test signals are
inserted into the transmitter datapath and appear at the transmitter output. So, it is important to switch off the power amplifier connected to the
device output, which also prevents signals from the antenna reaching the transmitter during calibrations. A 50 Ω termination is also needed
to prevent tone signals bouncing back from the power amplifier input and reaching the device transmitter output, thereby confusing internal
calibrations. The following paragraph summarizes the external system requirements.
External system requirements: For transmitter initial calibrations utilizing internal signal generation without loopback, power off the power
amplifier in the transmitter path during these calibrations. When the power amplifier is disabled, the load at the transmitter output should be 50
Ω.
Transmitter Initial Calibrations Utilizing Internal Signal Generation and ILB
Figure 153 shows a high level block diagram of system configurations for transmitter initial calibrations utilizing internal signal generation and
internal loop back (ILB) path.
analog.com
ADRV9001
Rev. A | 166 of 377