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82 Keysight N5990A MIPI M-PHY Receiver Test User Guide
4 Calibrations
Calibration Overview
Before any test procedure can be run, the MIPI M-PHY test system must
be calibrated. The calibration plane is given by the DUT input ports. The
receiver test signal characteristics such as the M-PHY signal generator
output voltage level, timing and jitter parameters are typically affected by
the signal transmission between the M-PHY signal generator output ports
and the DUT input ports. Transmission elements such as cables, power
dividers, splitters, and TTC (transition time converters) impact the signal
generator's output signal, for example, by reducing signal levels as a result
of losses and slowing down transition times. Thus, for any signal output
parameter selected by you (set value), the jitter and the signal received at
the DUT input ports (actual value) deviates from the set value. The
additional deviations can be caused by effects such as offset errors,
hysteresis, and non-linear behavior of the M-PHY signal generator.
calibration procedures compensate the deviations of the relevant signal
output parameter actual values from the set values over the required
parameter range.
All calibration procedures required for the MIPI M-PHY receiver testing are
included in the software. calibration procedures are implemented such
that the process is conducted as fast as possible and is also automated as
much as possible, for example, by minimizing the number of
reconfigurations of the hardware connections. Most of the calibration
procedures are run individually for each clock and data lane, for instance,
the LP and HS level calibrations and the inter-pair skew calibration.
Calibrations for all hardware configurations are explained in the following
sections.