Keysight U8903B User Manual page 199

Table 4-10 Analog/Digital/Bluetooth Analyzer > Functions > THD+N Level menu description (continued)
Menu Description
Press the Format softkey to select the format of the returned measurement reading.
– Off
Selecting Off will return the measurement reading without any formatting (raw value).
– Logarithmic
Selecting Logarithmic will return the measurement result by using the following formula:
20
Format
The result is returned in unit dBr.
– Linear
Selecting Linear will return the measurement result by dividing the measured level by the reference level. The result is
returned in unit x.
– Delta
Selecting Delta will return the meausrement result by deducting the reference level from the measured level. The result
is returned in unit ΔV. This is only available for the analog analyzer.
This is only available for analog analyzer.
Set to 0dB
Press the Set to 0dB softkey to store the measured level as the reference level, and set the measurement reading format to
Logarithmic.
Set result as ref. from Press the Set resul t as ref. from softkey to store the measurement result from the selected channel as the reference level.
Ref. Level Press the Ref. Level softkey to set the reference level value. There is only one reference level for each channel.
This is only available for the analog analyzer.
Ref. Imp
Press the Ref. Imp softkey to set the reference impedance value. This setting is only available if the unit is set to W and
dBm.
This is only available for the digital and Bluetooth analyzer.
Volt/FS
Press the Volt/FS softkey to set the volts/FS reference value.
This is only available for the digital analyzer.
Precision
Press the Precision softkey to enable or disable the precision mode.
Cal SPL Press the Cal SPL softkey to set the calibrator level value. This setting is only available when the unit is set to dBSPL.
Press the Freq Lock softkey to select the searching method for the fundamental frequency.
– Auto
Selecting Auto will allow the U8903B to search for the fundamental frequency automatically.
– Gen Lock
Selecting Gen Lock will allow the U8903B to search for the fundamental frequency based on the generator frequency
Freq Lock
value of the respective generator channel. You can select the generator channel by setting the Src Channel in the Meas.
Config. menu page. This Gen Lock method is only useful if you use the internal audio generator.
– Custom
If you have a known input signal, you can define the fundamental frequency value by setting the searching method to
Custom and setting the frequency value in Fund Freq.
Press the Fund Freq softkey to set the fundamental frequency value. This setting is only available when Freq Lock is set to
Fund Freq
Custom.
This is only available for analog analyzer.
Analog Notch Press the Analog Notch softkey to enable or disable the analog notch filter. This filter is used to emulate the analog notch
filter used in HP8903B.
Keysight U8903B User's Guide
Measured rms voltage
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log 10
⎝ ⎠
Reference level
Audio Analyzer Measurement Functions 4
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