Racal Instruments 3155, Руководство пользователя

Страница: 63 / 202

User Manual 3155
ArbConnection 3-11
Note
The normal color of the digital reading is dark blue. If
you modify the reading, the color changes to a lighter
shade of blue, indicating that the 3155 has not been up-
dated yet with the new parameter. Pressing Execute up-
dates the instrument and restores the color of the digital
readout to dark blue, indicating that the displayed value
is the same as the generator setting.
Also note that the digital readout has an autodetect
mechanism for the high and low limits. You cannot ex-
ceed the limits if you are using the dial but you can if
you use the keypad. In that case, the program will not
allow the download of an illegal parameter and an error
message displays.
Aside from the grouped buttons and parameters, there are two other
buttons in the upper right corner of this panel. These buttons provide
access to the Main Panel and also allow removal of the Waveforms
Panel from the screen.
10 MHz Ref
The 10 MHz Ref group provides selection between internal and ex-
ternal references. The 3155 has three reference options:
Internal – connects the CLK10 reference from P2 to the sample
clock generator. The accuracy and stability of the CLK10 exceeds
100ppm.
External – connects the front panel 10MHz Reference Input to the
sample clock generator. The accuracy and stability of this input is
determined by the 10MHz source, applied to this input.
TCXO – connects a 1ppm reference to the sample clock input. The
TCXO reference is optional and must be ordered at the time of your
purchase. Also note that the TCXO option is not normally shown on
this panel as it will only be there if the option is installed in your in-
strument.
Click on the Internal button to select the Internal CLK10 reference,
the External button to activate the external reference input, or the
TCXO to select the 1 ppm reference.