PicoVNA 106 6 GHz Vector Network Analyzer
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© 2017 Pico Technology
pv106ug r1
Basic connection guide for P1dB measurements. Calibration connection is shown on the left.
The instrument makes the measurement by setting the signal source (Port 1) frequency to the chosen value
and then stepping its power from –20 to 0dBm in 1 dB steps. The gain at each power setting is recorded.
On completion of the power sweep, a second order curve is fitted over a narrow section centered on the
point closest to the 1 dB gain compression point. The coefficients of this curve allow the actual P
1dB
point to
be calculated.
Note:
Choose the input attenuator with care. Ensure that there is no gain compression at the start of the
power sweep (–20 dBm at Port 1) and that at least 0.7 dB of gain compression is reached at the end of the
sweep (0 dBm at Port 1). A ‘?’ will be displayed if insufficient compression has been achieved.
After the attenuator values have been established and the DUT is in place (and powered up as appropriate),
enter the values into the P
1dB
control window (Fig. 6.34). Note that the output attenuation value impacts
directly on the P
1dB
value, it is important to enter an accurate value that takes into account all losses in the
output path, including any connecting cable that may have been used.
Clicking
Start
will perform the test, plot the gain and output power curves, and compute the P
1dB
. This,
together with the linear gain, will be displayed in the text boxes to the right of the
Start
button. The results
can then be printed (the window as displayed will be printed) or saved as a text file by clicking
or
Save
.
