Product specifications

Performing receiver and S-parameter calibrations

A calibrated receiver enables accurate and leveled pulsed-RF stimulus using

receiver leveling mode. In the calibration process, use a power sensor to create

source power and receiver calibration coefficients. In order for the power sensor

to read correct power levels, the pulse modulation must be turned off. Source

power calibration should be part of the calibration process. However, the source

power correction is not actually used to level the pulsed-RF stimulus; instead,

calibrated R1 receiver readings are used to level the pulsed-RF stimulus. The

example below shows measuring the amplifier output powers with the B receiv-

er on port 2. B receiver calibration coefficients are computed from the source

power calibration, and transmission tracking and port match coefficients of the

S-parameter error correction. Therefore corrected output power measurements

can be done without performing B receiver calibration independently.

Turn off pulse modulation

Sweep – Pulse Setup…

Pulse Gen for Source1: CW – OK

Perform S-parameter, source and receiver calibration

Cal – Start Cal – Cal Wizard… then follow the wizard

Check “Calibrate source and receiver power” when selecting a calibration type and ports

Switch to receiver leveling

Power – Power and attenuators… - Port 1 Leveling Mode: Receiver – R1

Turn on pulse modulation

Sweep – Pulse Setup…

Pulse Gen for Source1: Pulse – OK

If a different receiver is shown in the leveling mode pull down menu (Receiver – B,

for example), select R1 receiver for port 1 in the Receiver Leveling setup dialog

box. The calibration procedure is exactly the same as the CW stimulus procedure.

Figure 24 shows the calibrated S-parameter and input/output power measure-

ments under the pulsed-RF stimulus condition. Note that the calibration type anno-

tation shown at the bottom of the screen adds a “∆” (delta) when you turn on the

pulse modulation after the calibration. This indicates that a non-critical stimulus

setting was changed after the S-parameter calibration. Turning on pulse modulation

causes this indication, which does not affect the S-parameter calibration accuracy.

Figure 24. Calibrated wideband pulsed

S-parameters and absolute power

measurements with a comparison

between open loop and receiver

leveling modes