User manual

Configuring the AM700

3-18

AM700 Audio Measurement Set User Manual

When Audio Analyzer, FFT Analyzer, or Monitor is the running application,

calibration switches the analog acquisition system to a known test signal (a 120 Hz

symmetrical square wave). The AM700 then acquires the positive and negative peak

values seen at the output of the A and B high resolution A/D converters and at the

output of the A and B high bandwidth A/D converters. The values obtained are used

to determine the DC offset of the acquisition system at the time of calibration and

the calibration factor needed to remove the offset from the converted data values.

The calibration constants obtained are stored and used until a subsequent calibration

is done.

If the Digital Interface Tester application is running when calibration is performed,

the digital acquisition system offset is calculated, and the calibration factor obtained

is used to remove the offset from the peak-to-peak jitter measurements.

NOTE. Calibrate does not perform an analog acquisition system calibration when

Digital Interface Tester is the running application.

The Conversion Standards menu shown in Figure 3-13 permits you to define certain

values to be used in deriving measurement results.

Output dBm. This setting defines the value of the external load resistor. The divider

formed by load resistance and the internal series resistance selected for use (10 Ω,

150 Ω, or 600 Ω) is taken into account for the calculation (see Figure 3-14). Thus,

generator signal level can be specified in dBm, and the correct power will be

delivered to the load.

NOTE. This is calculated dBm, so if the external load is not as stated in the Output

dBm box, the output value stated in dBm will not be correct.

System

Conversion

Standards