Introduction 5
CG635 Synthesized Clock Generator
TOGGLE
When stopped, toggles the logic state of the output
INIT
Resets the instrument to its default settings
STATUS Displays
instrument
status
PRBS ON
If installed, turns on the pseudo-random binary generator
PRBS OFF
If installed, turns off the pseudo-random binary generator
FREQ/2
Divides the current frequency by 2 and displays frequency
FREQx2
Multiplies the current frequency by 2 and displays frequency
REL
ș
= 0
Defines the current phase to be 0 degrees and displays phase
ș
+ 90°
Increments the phase by 90 degrees and displays phase
GPIB
Enables the GPIB remote interface. Disables RS-232.
ADDRS
Displays / Sets the GPIB primary address for the CG635
RS-232
Enables the RS-232 remote interface. Disables GPIB.
DATA
Displays the most recent data received over the remote interface
ĸ
Increases the current step size by the next exact factor of ten
(Located in the MODIFY section.)
ĺ
Decrease the current step size by the next exact factor of ten
(Located in the MODIFY section.)
A more detailed description of each of the secondary functions is given in the Secondary
Functions section of the Operation chapter (page 22).
The secondary functions can only be accessed when SHIFT mode is active, which is
indicated by the SHIFT LED being turned on. The SHIFT mode can be toggled on and
off by pressing the ‘SHIFT’ key. Therefore, to increase the frequency by a factor of four,
you would press the ‘SHIFT’ key to activate SHIFT mode, and then press ‘4’ twice to
execute FREQx2 twice. Pressing ‘SHIFT’ again toggles SHIFT mode off.
Most of the secondary functions will automatically toggle SHIFT mode off when
executed. FREQ/2, FREQx2,
ș
+ 90°, and TOGGLE are exceptions to this rule. This
allows the user to easily sweep frequency or phase without having to continually
reactivate SHIFT mode.
Secondary functions that have an arrow ( ) printed after them, such as INIT, GPIB,
ADDRS, and RS-232, require that the user press the key ‘Hz’ to complete the action. For
example, to initialize the instrument to its default settings, you would sequentially press
‘SHIFT’, ‘INIT’, ‘Hz’.
Cancel
The ‘SHIFT’ key also functions as a general purpose CANCEL key. Any numeric entry
which has not been completed by pressing a units key, can be canceled by pressing the
‘SHIFT’ key. Because of the dual role played by the SHIFT key, the user may have to
press ‘SHIFT’ twice to reactivate SHIFT mode. The first key press cancels the current
action, and the second key press activates SHIFT mode.
