Keysight U8903A, User Manual, Page: 117 / 167

Audio Analyzer Measurement Functions 5
Keysight U8903A User’s Guide 117
Measurement Functions
This section describes the measurement functions.
Frequency
Frequency is a common and basic measurement function which is expressed in
hertz (Hz). The U8903A uses software algorithm to detect the period of a
repetitive waveform and the frequency is computed from the reciprocal of the
period.
To obtain better accuracy and resolution, autoranging should be enabled. For low
frequency signals, set a longer measurement time to get better and more stable
readings. Input filters can also be activated to remove unwanted high frequency
noise from the measured signal, allowing more stable readings.
AC voltage level (Vac)
This is the most common measurement function of an AC signal. The U8903A
provides three types of AC level detection consisting of RMS, Peak-to-Peak, and
Quasi Peak. Refer to Chapter 3 , “AC level detection” on page 78 for more
information. When the RMS detection method is selected, the AC voltage
measurement is expressed as an RMS value. Likewise, if the Peak-to-Peak
detector is selected, the result is a peak-to-peak value.
As an example, for a 1 Vrms sine input signal, the display will show 1 V if the RMS
detector is selected. On the other hand, if the Peak-to-Peak detector is selected,
the display will show 2.828 V (1.414 × 2).
The Quasi Peak detector is normally used with the CCIR filter per the IEC 60468
standard.