User manual

Audio Generator
AM700 Audio Measurement Set User Manual
4-29
To switch between NVRAM and ROM, touch the Drive soft key. If there is a
directory available in the selected drive, the Change Directory soft key can be used
to move into that directory if it is selected. To select a directory or file in the list,
touch the directory or file name to make the selection. Alternately, the large control
knob can be used to scroll through the choice in the list. When the correct file has
been highlighted, touch the Select soft key to make the selection and exit the screen.
Touching the Cancel soft key aborts any changes and exits the screen.
Advanced Digital Interface
The AES11 audio standard recommends the use of a master clock for audio in studio
applications. The AM700 generates a digital audio reference signal that simulates
this master clock, allowing you to test the ability of equipment to lock to a
reference. Controls in the Advanced Digital Interface screen, shown in Figure 4-11,
also allow you to precisely adjust the frequency or phase of the digital audio
generator clock with respect to an external reference. This can be useful, for
example, when testing the lock-in range of a device under test or its behavior with a
drifting clock.
Several soft key selections in the Interface Clock Frequency Control section of this
screen determine the characteristics of digital generator and reference clocks.
Selections in this screen area are: Frequency Mode, Variable Freq, Offset, and Phase
Offset. In all cases, the clock frequency of the digital audio output is the same as
that of the reference output.
NOTE. Many of these controls are also accessed using the Digital Interface Tester
menu. This feature permits immediate access to the digital generator signal
parameters without the need to call up the Generator Control panel. When accessed
from within the Digital Interface Tester, the measurement application remains
displayed when adjusting the digital signal parameters.