Berkeley Varitronics Systems YellowFrog-Pro User Manual page 6

This indicates the number of forward samples averaged over 100
measurements.
Touch this button to change the input frequency measured. You
will be taken to a numeric keypad screen where you enter in
any frequency between 500 MHz and 4000 MHz with accuracy
of 5 places to the right of the decimal.
This indicates the reflected power in dBm.
This indicates the VSWR (Voltage Standing Wave Ratio)
Power can be displayed in dBm or Watts. This can be
toggled on or off in the Main Options menu.
TDD should only be shown when you want to
measure a TDD (Time Division Duplex). This is a
mode used in TDD LTE and future 56 bands. It can be
toggled on or off in the Main Options menu.
This horizontal scale represents the power measured
from -20 dBm through +53 dBm.
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