UG-1828 Preliminary Technical Data
Rev. PrC | Page 148 of 338
prevents the calibrations tones from reaching antenna through RF coupling. 50Ω termination is needed to prevent tone signals bouncing
back from external LNA output and reaching receiver input confusing internal calibrations.
Configure the Initial Calibrations Through TES
To achieve optimal performance, all initial calibrations should be enabled. However, the TES provides the capability to allow user to
disable some initial calibrations, mainly for debugging purpose. Table 54 summarizes a comparison for all initial calibrations in terms of
“User Override Capability”, “Run at Boot”, “Signal Used by Calibration”, “External Termination Needed” and “Dependency”. A minimum
set of initial calibrations must be rerun after “LO changes equal to or more than a certain range (for example, 100MHz) or divide by 2
boundary change” and this set of initial calibrations is defined by the bit mask “ADI_ADRV9001_INIT_LO_RETUNE = 0x000B902B” in
“adi_adrv9001_InitCalibrations_e” enumerator type as suggested by Table 54. Note use can also rerun the full suite of initial calibrations
to achieve the optimal performance. Figure 144 and Figure 145 demonstrate the Tx LO leakage performance and Tx image rejection
performance under different initial calibrations. In this experiment, the LO is swept from 100MHz to 2.9GHz in 100MHz step size. The
blue line stands for the performance if the full suite of initial calibrations are rerun at each LO change. The red line stands for the
performance of running the full suite of initial calibrations and then the minimum set of initial calibrations alternatively (full initial
calibrations for LO=100MHz, 300MHz, 500MHz,… and minimum initial calibrations for LO=200MHz, 400MHz, 600MHz,…. ). Grey
line stands for the performance of running the full suite of initial calibrations and then no initial calibrations alternatively (full initial
calibrations for LO=100MHz, 300MHz, 500MHz,… and no initial calibrations for LO=200MHz, 400MHz, 600MHz,…. ). It can be seen
clearly that without rerunning any initial calibrations after LO change = 100MHz will cause a significant performance penalty. However,
the optimal performance (achieved by rerunning the full suite of initial calibrations) can be largely kept if rerunning the minimum set of
initial calibrations.
Figure 144. Tx LO Leakage Performance when LO Change = 100MHz with Full Init Cals, Min Init Cals and No Init Cals
Figure 145. Tx Image Rejection Performance when LO Change = 100MHz with Full Init Cals, Min Init Cals and No Init Cals
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