Analog Devices ADRV9001 User Manual page 112

UG-1828
PA SWITCH OFF
Figure 98. Transmitter Initial Calibration System Configuration with Signal Generation Without Loop Back
As shown in Figure 98, an internal signal generator inserts calibration signals 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 utilize 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 99 shows a high level block diagram of system configurations for transmitter initial calibrations utilizing internal signal
generation and ILB path.
DUPLEXER
(TDD,FDD)
Figure 99. Tx Initial Calibration System Configuration with Signal Generation and Internal Loop Back
As shown in Figure 99, TX_LB_PD, TX_QEC, TX_LO_LEAKAGE, TX_DCC, and TX_ATTEN_DELAY utilize the ILB for calibrations.
TX_LO_LEAKAGE and TX_QEC calculate the initial correction parameters. TX_LB_PD provides a measurement of the loop back path
delay for TX_LO_LEAKAGE and TX_QEC algorithms. Both TX_LO_LEAKAGE and TX_QEC calibrations sweep through a series of
attenuation values, creating a table of initial calibration values. Then, during operation and upon application of a new transmitter
attenuation setting, the corresponding QEC and LO_LEAKAGE correction values are applied to the transmitter channel by the
ADRV9001 ARM. TX_DCC estimates the duty cycle error in the digital domain but applies the correction in the analog domain.
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. PrA | Page 112 of 253
Preliminary Technical Data
DATA PORT
CMOS-SSI
OR
FROM
LVDS-SSI
BBP
SIGNAL
GENERATOR
TO
BBP
DATA PORT
CMOS-SSI
OR
LVDS-SSI
FROM
BBP
SIGNAL
GENERATOR