Operation 13
CG635 Synthesized Clock Generator
Operation
Front-Panel User Interface
The previous chapter described the function of the front-panel keys based on their
location on the front panel. This section provides guidelines for viewing and changing
instrument parameters independent of their location on the front panel.
Power On
At power on, the CG635 performs a number of self tests to verify that various internal
components are operating correctly. If any of the tests fail, the CG635 will briefly display
“Failed” after the test. In such a case, consult the troubleshooting section later in this
chapter before contacting SRS or an authorized representative to repair the unit.
After the self tests have completed, the CG635 will recall the latest known instrument
settings from nonvolatile memory and be ready for use.
The CG635 continuously monitors front-panel key presses and will save the current
instrument settings to nonvolatile memory after approximately ten seconds of inactivity.
To prevent the nonvolatile memory from wearing out, however, the CG635 will not
automatically save instrument settings that change due to commands executed over the
remote interface. The remote commands *SAV and *RCL can be used to explicitly save
instrument settings over the remote interface, if desired. See the CG635 Remote
Programming chapter for more information about these commands.
The CG635 can be forced to boot up at factory default settings. This is accomplished by
pressing and holding the ‘BACK SPACE’ key during power up, until the initialization is
complete. All instrument parameters will be set back to their default values, including the
enabled remote interface and the GPIB address. See the Default Factory Settings section
later in this chapter for a listing of the default settings.
Displaying a Parameter
The CG635 has six main displays which are activated by pressing the keys in the
DISPLAY section of the front panel. The function of each key is summarized in Table 6.
Table 6: DISPLAY Section Keys
Label
Value Shown in Main Display When Pressed
FREQ Current
frequency
PHASE Current
phase
Q / Q
¯ HIGH
Voltage for a Q / Q
¯ logic high state
Q / Q
¯ LOW
Voltage for a Q / Q
¯ logic low state
CMOS HIGH
Voltage for a CMOS logic high state
CMOS LOW
Voltage for a CMOS logic low state
