Analog Devices ADRV9001 User Manual page 145

Preliminary Technical Data
interference. Some calibration algorithms, such as TX_LB_PD, TX_QEC, TX_LOL, TX_DCC and TX_ATTEN_DELAY further require
the use of observation datapath through ILB or ELB to receive the transmitted signal so that a joint analysis can be performed by
observing the relationship between the transmitted signal and received signal. As aforementioned, currently, only ILB feedback path is
supported for initial calibrations.
Transmitter Initial Calibrations Utilizing Internal Signal Generation Without Loopback
Figure 139 shows a high level block diagram of system configurations for transmitter initial calibrations requiring inserting signals into
the transmitter datapath without using loopback path.
PA SWITCH OFF
Figure 139. Transmitter Initial Calibration System Configuration with Signal Generation Without Loop Back
As shown in Figure 139, an internal signal generator inserts calibration signals (red) into the transmitter datapath. The data port is
disabled during initial calibrations to avoid producing interference. TX_PATH_DELAY is performed in the digital domain, whereas
TX_BBAF and TX_BBAF_GD are performed in the analog domain. All of them use the signal generator to insert tones for calibration.
During all these calibrations, test signals inserted into the transmitter datapath can appear at the transmitter output, so it is important that
the power amplifier connected to the device output be switched off, which also prevents signals from the antenna reaching the transmitter
during calibrations. 50 Ω termination is also needed to prevent tone signals bouncing back from power amplifier input and reaching the
device transmitter output, thereby confusing internal calibrations. The following paragraph summarizes the external system requirement.
External system requirement: for transmitter initial calibrations utilizing internal signal generation without loopback, the power amplifier
in the transmitter path should be powered off during these calibrations. When the power amplifier is disabled, the load seen at the
transmitter output should be 50 Ω.
Transmitter Initial Calibrations Utilizing Internal Signal Generation and ILB
Figure 140 shows a high level block diagram of system configurations for transmitter initial calibrations utilizing internal signal
generation and ILB path.
DUPLEXER
(TDD,FDD)
Figure 140. Tx Initial Calibration System Configuration with Signal Generation and Internal Loop Back
0°
PA
90°
ADRV9001
LNA
LNA SWITCH OFF
ILB
PA
PA SWITCH OFF
DAC
LPF
LO1
TX_PATH
DELAY
LO2
DAC
LPF
TX_BBAF
TX_BBAF_GD
HP ADC
LPF
LO1
LP ADC
0°
90° LO2
LP ADC
HP ADC
LPF
DAC
LPF
LO1
0°
90° LO2
DAC
LPF
Rev. PrC | Page 145 of 338
DATA PORT
CMOS-SSI
OR
FROM
LVDS-SSI
BBP
SIGNAL
GENERATOR
TO
BBP
DATA PORT
CMOS-SSI
OR
LVDS-SSI
FROM
BBP
SIGNAL
GENERATOR
UG-1828