User manual

Audio Analyzer
4-52
AM700 Audio Measurement Set User Manual
Making Valid Measurements
The Audio Analyzer application must be configured properly if it is to yield
meaningful results. Values generated by Audio Analyzer measurements are not
meaningful in all cases. Whether or not a measurement is meaningful depends on
the type of input test signal.
For example, crosstalk and separation measurements require placing a signal on one
channel and monitoring the other (undriven) channel for the presence of audio.
When the AM700 has a signal on both channels, a measurement such as phase
difference has value, but any displayed crosstalk and separation readings are
meaningless. However, when the signal is removed from one channel, crosstalk and
separation readings on the silent channel now contain useful information, while any
displayed phase difference readings become meaningless.
Other measurements require special signals. For example, the IMD (intermodulation
distortion) measurement needs two sine waves in order to measure their distortion
product. If the two sine waves of the IMD test signal are not present, any displayed
IMD measurement value is meaningless.
Configuring Input Channels
As with many AM700 applications, the Audio Analyzer makes measurements on
two input channels. You can specify input signals for the two channels by pressing
the Configure button and touching the Input Selection soft key to display the Input
Configuration screen. Input Selection is discussed on page 3-2 in Configuring the
AM700.
In this screen, select the desired type of input by touching the Channel 1 or
Channel 2 selector to display the input selection pop-up menu. Turn the control
knob to the desired input type and touch the selector to accept it. Repeat for the
other input channel, if desired.
NOTE. If either Channel 1 or Channel 2 is not enabled, stereo measurements are not
enabled. Also, if the Channel 1 and Channel 2 sources are not a stereo pair, stereo
measurements are not enabled. For instance, if the Channel 1 source is the High
Resolution generator and the Channel 2 source is the High Bandwidth generator, the
inputs are not a stereo pair, so stereo measurements cannot be made.