3 Instrument Configuration82 Keysight U8903A User’s GuideFrequency LockThe fundamental frequency lock setting is only applicable when Function 2measurement of the specified channel is set to SINAD, THD + N Ratio, or THD + NLevel. If Function 2 measurement is set to SINAD, the default frequency lock typeis Gen. Lock, whereas for THD + N Ratio and THD + N Level, the default frequencylock type is Auto.When the frequency lock type is set to Auto, the fundamental frequency is determinedby the measured signal frequency of the frequency measurement function. Function 1measurement is set to Frequency if the frequency lock type is Auto.When the frequency lock type is set to Gen. Lock, the fundamental frequency isdetermined by the frequency value set at the corresponding generator channel.Figure 3-7 Frequency lock
