Audio Precision ATS-2, Начало работы

Страница: 47 / 76

Example Sweep: Amplitude Linearity
For this example, we will measure the amplitude linearity of the ATS-2.
With the analog output connected to the analog input, we sweep the
amplitude of the analog generator over its full range, and plot the ratio of
the level measured by the analyzer to the generator output level, in dB.
Any amplitude non-linearity in the system will show as a deviation from
0 dB.
First, perform a New Test, turn the analog generator on, and set both
analog input channels to GenMon so that the generator signal is sent
directly to the analog input. Now open the Sweep panel and make the
following changes:
§
Click the Source 1 browser button, and choose ‘Analog Generator’ as
the instrument and ‘ChA Amplitude’ as the setting.
§
Change the Start value for Source 1 to 100 µV. (ATS understands the
prefix ‘u’ to stand for ‘µ’.)
§
Choose the dBg A units for Data 1 by clicking on the arrow next to
the Top field, and choosing the ‘dBg A’ line from the list. The dBg A
units (decibels relative to generator channel A) show the ratio of the
reading to the level of the analog generator, in dB.
§
Set the Data 1 Top value to 0.1, and the Bottom value to –0.1.
Click Go to start the sweep. The ranging relays will click as the
generator changes amplitude. The result will be a curve that deviates only
slightly from 0 dBg A, as shown in Figure 17.
Quick Guide to Sweeps Chapter 5: Quick Guides
Getting Started with ATS-2 37
Figure 16. Current
workspace after
frequency
response sweep,
showing typical
results.