UNI-T UTS3000B/A Series User Manual page 67

%of OBW Power: It can be used to change the percentage of signal power used in determining
occupied bandwidth. User can change the percentage by using the numeric key, rotary knob, direction
key, or touch the panel menu.
x dB: the number of dB that defines the highest point (P1) in the signal, for measuring the transmit
bandwidth, the transmit bandwidth should within the span of OBW. This function is independent of the
calculation of OBW.
The calculated result of XdB bandwidth is also called transmit bandwidth (EBW). A direction marker (F1
and F2) is placed at each of the two frequency of the left and right side of the highest point (P1). The
amplitude of the two frequency is lower to dB number of the highest point（P1）, it should be the same
with the dB value specified by the user. Calculating the total power between the two markers.
The frequency F1 and F2 are defined as the farthest frequency of xdB which higher and lower P1. The
transmission bandwidth is the difference between F2-F1, the range is from -100.0 dB to -0.1dB. Users
can change the xdB by using the numeric key, rotary knob, direction key, or touch the panel menu.
Note
The asterisk next to the xdB bandwidth value indicates that the result was not obtained under optimal
setting of the spectrum analyzer. If your primary concern is transmit bandwidth, select maximum hold.
Then Press [Trace]>Detector>Peak Detection. The obtained peak data will ensure the accuracy of the
transmission bandwidth measurement.
Meas Preset: Reset all parameters of the current measuring mode to factory setting.
Third-order Intercept
5-4
Figure TOI
Third-order intermodulation (TOI) measurement is used to calculate and display the output cutoff (IP3),
and placed direction marker on a trace to indicate the direction of the measured signal and third-order
product.
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