Specifications

22
Innovative
Applications
Control relative
magnitude and phase
between two sources
for active output-load
control
(Option 088)
Amplifier load-pull measurement challenges
• Amplifier gain, output power, and power efficiency are commonly measured under differ-
ent output-load conditions to determine the optimum large-signal match
• Traditional approach uses mechanical tuners which can handle high power, but are slow
and cannot supply highly reflective loads
PNA-X with source-phase control provides
• Control of second source to electronically tune reflection coefficient at output of amplifier
• Fast tuning speed and full reflection
• Match correction for accurate amplitude and phase control
• Measurements of amplifier output power, match, gain, and PAE under different load
conditions
Example of load circles generated by keeping the magnitude of
G
L
constant while sweeping phase
Generate arbitrary
output-load impedances
by controlling the mag-
nitude and phase of the
signal coming out of port
3 while the DUT is driven
from port 1
Tips from the experts
• Measurement setups can use receiver (R3, C...) or wave
(a3, b3…) terminology
• Use the equation editor to calculate the power deliv-
ered to the load (forward power - reverse power) as
sqrt(pow(mag(b3_3),2) - pow(mag(a3_3),2))
• Use mechanical tuners and external software for hybrid
load-pull systems that can handle high output power and
achieve full reflection
• When using external signal sources, connect instruments to
a common 10 MHz frequency reference