Trace Menu R&S
®
ZVA/ZVB/ZVT
1145.1084.12 4.32 E-6
Definition:
The Power Added Efficiency (PAE) is the ratio of the added RF power generated by an active two-port
device (e.g. an amplifier) to the supplied DC power P
DC
. The added RF power can be expressed as the
difference between the power of the outgoing wave b
2
at the output of the DUT and the power of the
incident wave a
1
at the input of the DUT; hence:
Positive PAE values indicate a gain in the RF power, negative values an attenuation. The PAE is
always smaller than 1.
Remote
control:
CALCulate<Ch>:PARameter:MEASure "<Trace_Name>", "PAE21" |
"PAE12" |...
Create new trace and select name and measurement parameter:
CALCulate<Ch>:PARameter:SDEFine "<Trace_Name>", "PAE21" |
"PAE12" |...
DC Power Measurement
The power P
DC
supplied to the DUT can be measured using either one of the DC inputs DC MEAS
10V (for large voltages), DC MEAS 1V (for small voltages) or both inputs. The DC Power panel in the
PAE dialog suggests different models involving different test setups and approximations. The models
are selected by means of the radio buttons in the DC Power panel; they depend on the properties of the
DC power supply (constant current I
DC
or constant power U
DC
) and an optional precision resistor R used
to measure the DC current. The values I
DC
, U
DC
, and R determine the Constants c and k. These
constants must be entered in the DC Power panel, using the appropriate physical units, before a
particular model can be activated.
• I
DC
= const., R = 0 —> P
DC
= c * U (DC Meas 10 V). Assume that the DC power supply
provides a constant current I
DC
and that the voltage applied to the DUT is measured via DC
MEAS
10 V (R = 0). P
DC
= I
DC
* U(DC MEAS 10 V), hence the Constant c must be set equal
to I
DC
. The unit field shows the SI unit of a current (W/V). The input field for k is disabled (k is not
used).
• U
DC
= const., R << R
DUT
, P
R
= 0 —> P
DC
= c * U (DC MEAS 1 V). Assume that the DC power
supply provides a constant voltage U
DC
and that the current through the DUT is measured by
means of a precision resistor R connected in series and DC INP 2. If R << R
DUT
the power
consumption of the resistor can be neglected so that P
DC
= U
DC
/ R * U(DC MEAS 1 V), hence
the Constant c must be set equal to U
DC
/ R. The unit field shows the SI unit of a current (W/V).
The input field for k is disabled (k is not used).
• R << R
DUT
, P
R
= 0 —> P
DC
= k * U (DC MEAS 10 V) * U (DC MEAS 1 V). Assume that the
DC power supply provides an arbitrary (not necessarily constant) voltage U
DC
and current I
DC
.
The current through the DUT is measured by means of a precision resistor R connected in
series and DC INP 2. The voltage applied to the DUT and R is measured via DC MEAS
10
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