The Model 278, a 0.01 Hz to 12 MHz Programmable Synthesized
Function Generator, can operate in continuous, triggered,
gated, burst, synthesized, external reference, or external
phase lock modes with output levels to 20 volts peak-to-peak.
The synthesized mode has 5 digits of frequency resolution
with 0.0005% accuracy, or it can be locked to an external 10
MHz (zero-crossing or TTL) frequency reference for greater
accuracy and stability. In addition, the separate
Synthesizer circuit acts as a highly accurate internal
The Generator can produce sine, triangle, square, square
complement, and pulse waveforms as well as dc and external
Data entry is from the front panel or GPSB (IEEE-488, 1978).
Numeric input is entered in free format: fixed, floating, or
exponential notation. Parameters may be entered in any
order. Internally, all entries are interactively checked for
errors and displayed on the front panel, or they may be
accessed through the GRIB.
Output level is specified from 10 mV to 10 Vp-p into a 500
termination and 20 mV to 10 Vp-p into an open circuit with 3
digits of resolution. Offset can be programmed to vary the
waveform base line up to ± 10V, or in the dc function, to
vary the dc output.
All inputs and outputs are protected against short circuits
and excessive voltages between ±15V. The function output is
further protected against voltage inputs up to 140 Vac or
±200 Vdc. Activation of the protection circuits will cause a
front panel error message and may cause a GPIB service request.
Up to 100 sets of complete front panel settings can be
stored in memory. The memory has a non-rechargeable lithium
battery back up for up to 6 months (typically 1 to 2 years).
A “low battery” warning will be indicated on the display
when the battery voltage drops to 80% of its normal voltage.
WARNING This equipment uses a BR-1/2A, 3V
lithium battery, that contains less than
0.3 grams of lithium. To prevent the release of a
potentially harmful substance, DO NOT RECHARGE, SHORT
CIRCUIT, DISASSEMBLE, OR APPLY HEAT TO THE BATTERY. In
addition, observe correct polarity when replacing.
instruments manufactured prior to serial number 7230039 may
be limited to 40 sets of stored settings without battery
back-up. But if an option (previously identified as Option
001) was installed, there will be a total of 100 sets of
stored settings with non-rechargeable battery back-up as
described in this manual.