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GUIDE TO OPERATION
INTRODUCTION
The DG535 Digital Delay and Pulse Generator
can provide four precisely timed logic
transitions, or two precisely controlled pulses.
The four digitally controlled time intervals may
be programmed from the front panel or via the
GPIB. Front panel BNC's provide high slew rate
outputs at TTL, NIM, ECL or continuously
adjustable levels. The outputs may be set to
drive either 50
Ω
or high impedance loads.
The high accuracy (1 ppm), precision (5 ps),
wide range (0 to 1000 s), and low jitter (50 ps
rms) recommend the DG535 as the solution to
many difficult timing problems in science and
industry.
FRONT PANEL OPERATION SUMMARY
POWER BUTTON
The unit is turned on by depressing the POWER
button. All instrument settings are stored in
nonvolatile RAM, and so the settings are not
affected by turning the power on and off. The
model, firmware version, and serial numbers for
the unit will be displayed briefly when the
power is first applied.
LIQUID CRYSTAL DISPLAY
The 20 character LCD is the user interface for
all front panel programming operations. The
wide viewing angle LCD is backlit by an
electroluminescent panel for convenient
operation in low light level conditions. When
the keypad is in the cursor mode, the contrast of
the LCD may be adjusted for optimum viewing
by the two right most keys on the front panel.
MENU KEYS
Six Menu Keys select the function to be
programmed. Most menu items are self-
explanatory:
TRIG defines the trigger source
DELAY is used to adjust the four digital
delays
OUTPUT sets the output pulse levels
GPIB allows the user to see data received via
the GPIB and to set the GPIB address
STORE and RECALL provide a convenient
method to save all of the instrument
settings.
Detailed descriptions of each of these menus will be
given.
DATA ENTRY KEYS
Sixteen keys are used to enter and modify data.
There are three modes of operation for this keypad:
the mode is indicated by the three LED's in the
center of the panel. The cursor mode (< >) allows
individual digits to be modified in a fashion similar
to the operation of thumbwheel switches. The
numeric mode (NUM) allows the data to be entered
as a numeric string. The remote mode (REM) lets
the GPIB controller lock-out front panel operation.
The key beneath the Mode LED's allows the user to
change the keypad mode, if not locked-out by the
GPIB controller.
TRIGGER STATUS
Five LED's are used to indicate the trigger status.
The TRIG LED blinks each time the unit is
triggered, the BUSY LED is on whenever a timing
cycle is in progress, the RATE LED is lit if a trigger
is received while BUSY. The INT LED indicates
that the internal rate generator is the trigger source,
and the 50
Ω
LED is on when the EXT TRIG input
is terminated in 50
Ω
. The EXT TRIG BNC is the
input for external triggers.
DELAY OUTPUTS
There are five delay output BNC's: T0, A, B, C and
D. T0 marks the start of the timing interval and is
most useful when an internal trigger source has been
selected. The logic transitions at the outputs of A, B,
C and D may be set from 0 to 1000s in 5 ps
increments with respect to T0. The outputs may be
programmed for TTL, NIM, ECL or adjustable
output levels, and can drive 50
Ω
or high impedance
loads. The polarity of each output may be set to
provide a rising or a falling edge when the channel
times out. The outputs will remain asserted until 800
ns after the longest delay.
