Transmitter/Receiver/Observation Receiver Signal Chain Calibrations; Initial Calibrations - Analog Devices ADRV9001 User Manual

Preliminary Technical Data

TRANSMITTER/RECEIVER/OBSERVATION RECEIVER SIGNAL CHAIN CALIBRATIONS

In ADRV9001, to achieve optimal performance, an ARM performs calibrations which can be classified into two categories: initial
calibrations performed at the initialization time before the device is operational; and tracking calibrations performed regularly while the
device is operational.
Initial calibrations are considered as a part of the device initialization which moves the device from "STANDBY" state to
"CALIBRATED" state to prepare for transmit/receive operations. Tracking calibrations are performed regularly on-the-fly while the
device is operational to track the changes such as attenuation, temperature and etc. As discussed in Rx Signal Chain Section of this User
Guide, ADRV9001 includes 2 Tx and 2 Rx. for each Rx, besides acting as a primary data channel for receiving RF signals, it could also
serve as an observation channel, which receives Tx signals through loopback paths. The observation channel could be controlled fully by
user (ORx) or internally controlled by the device for some Tx initial and tracking calibrations. Note for some systems such as FDD 2T2R,
the Tx tracking calibrations requiring loopback paths could not be performed since the observation channel is not available. (Please refer
to ADRV9001 Example Use Cases section for more details.)
Most initial calibrations utilize internally generated tones or wideband signals for calibration which need user to satisfy external system
requirements. This topic will be discussed in more details in later sections. Different from initial calibrations, tracking calibrations
usually utilize the real-time traffic data for calibration. Therefore, tracking calibrations are transparent to users which do not require any
user intervention. Both initial and tracking calibrations are scheduled and performed by the ARM.

INITIAL CALIBRATIONS

There are three types of initial calibrations, which are
System (non-channel related) initial calibrations
•
Initial calibrations for RF PLLs to calibrate the RF PLL for very fast frequency hopping mode (currently not available),
•
Aux PLL initial calibration (currently not available).
•
Tx initial calibrations
•
Quadrature Error Correction (QEC),
•
• Local Oscillator (LO) Leakage,
Loop Back Path Delay (LB PD),
•
Duty Cycle Correction (DCC),
•
Baseband Analog Filter (BBAF),
•
Baseband Analog Filter-Group Delay (BBAF GD),
•
Attenuation Delay (ATTEN DELAY),
•
Digital to Analog Converter (DAC),
•
Path Delay.
•
Rx initial calibrations
•
High Power ADC Resistor/Capacitor (HP ADC RC),
•
High Power ADC Flash offset (HP ADC Flash),
•
High Power ADC DAC (HP ADC DAC) (currently not available),
•
• Duty Cycle Correction (DCC), Low Power ADC (LP ADC),
• Transimpedance Amplifier
3-dB Cutoff Frequency (TIA Cutoff),
•
Transimpedance Amplifier Group Delay,
•
Wideband Quadrature Error,
•
Frequency Independent Quadrature Error,
•
Internal Loop Back LOD (ILB LOD) (currently not available), DC Offset (RF DC),
•
Gain Path Delay.
•
Note Rx initial calibrations are also required to be performed on loopback paths to prepare for Tx initial and tracking calibrations.
To successfully perform all the initial calibrations, the ADRV9001 device should be configured properly. This is fully controlled by the
ADRV9001 ARM therefore no user interaction is required. However, besides the internal configurations, there are also requirements for
the external system. For example, during some Tx initial calibrations, tones are generated and present at Tx output. Therefore, user
should ensure appropriate level of isolation from ADRV9001 Tx output to antenna to make sure that test tones are not transmitted by
the system. This isolation could be achieved by disabling power amplifier during Tx initial calibration.
Rev. PrA | Page 107 of 253
UG-1828