Keysight Technologies U2000 Series Demo Manual page 6

06 | Keysight | N1918A Power Analysis Manager and U2000 Series USB Power Sensors - Demo Guide
Pulse Power Measurement Demonstration
Pulse power is determined by measuring the average power of the pulse and then
dividing the measurement results by the pulse cycle value to obtain the pulse power
reading, as expressed by the following equation:
P = P / Duty Cycle
p avg
The measurement result is a mathematical representation of the pulse power rather
than the actual measurement with the assumption of constant peak power. To ensure
accurate pulse power readings, the input signal must be a repetitive rectangular pulse
with a constant duty cycle.
Power
Figure 5. Pulse power calculation
Objective
To demonstrate the capability of the Power Panel to carry out pulse power measure-
ment using the U2000 Series USB power sensor.
In this demonstration, we supplying a pulsed signal with the pulse width of 10 μs and
a pulse period or pulse repetition interval (PRI) of 40 μs. The pulse signal is set to the
power level of approximately 0 dBm. The measured average power of the signal is
–6.24 dBm (See Figure 6). The duty cycle is known to be 10 μs divided by 40 μs, which
is 25%—this value can be configured in the Power Panel. This generates a pulse reading
of –0.22 dBm (See Figure 7).
To understand what the USB power sensor does, we can look at the duty cycle calcula-
tion. The equation, Average Power = 10 log (Pulse Width/PRI), provides the difference
between average power and pulse power. The calculated value in this demonstration
shows that the average power is –6.02 dBm lower than the pulse power. The Power
Panel makes this correction to show the pulse power using the provided duty cycle.
Instructions
On the ESG
1. Set the instrument to default
2. Set the frequency and amplitude
3. Set the pulse signal
4. Activate the pulse signal
B (Pulse Repetition Interval)
A
Duty Cycle =
B
Measured
Average Power
Time
A (Pulse Width)
Press [Preset]
[Frequency]
1. Press
2. Press [Amplitude]
1. Press [Pulse] Pulse Period
2. Pulse Width
Toggle Pulse On/Off
MHz
1900 >
0 > dBm
> 40 > usec
> 10 > usec
to "ON"