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BK Precision 4070A User Manual Rev.2.2
51
7.6 Pulse Generator Mode
1. Positive Only
This field, when set to “Y”, does not let the output signal go below 0V. This feature is handy when driving
circuitry that cannot accept negative voltages. This feature eliminates having to readjust the offset voltage to obtain
a positive only signal every time the output level is changed. When this field is set to “Y”, the output level is halved,
so that the output signal swings from 0V to ½ the specified level into a 50O load (or 0V to the specified level into an
open circuit).
NOTE: If you are using the Pulse Mode to drive digital logic, you should use the SYNC Out connector on the
front panel. This signal has the same shape as the SIG Out signal, but comes from a TTL/CMOS driver.
2. Duty Cycle
In this field enter the duty cycle for the pulse waveform, from 0% (always low) to 100% (always high) in 1%
steps. The duty cycle is the percentage of the waveform period that the output is high. A waveform with a 10% duty
cycle for example means that the output is high for 10% of the time and low for the remaining 90% of the waveform
period.
3. Continuous / Triggered mode
In this field select whether the waveform is generated continuously or on a single event basis. If you select
Continuous mode, then the waveform is immediately restarted once the end of the waveform is reached. If you
select a Triggered mode, then the waveform is halted after the last point is reached, and the waveform is not
restarted again until another trigger occurs. The trigger may come simultaneously from three sources:
1. Pressing the Trigger key
2. Applying a low-to-high transition on the Ext. Trig In connector
3. Sending an ASCII "T" to the RS-232 port
To set Continuous mode, press 1. To set Triggered mode, press 0. Pressing arrow keys or rotating the wheel will
toggle the mode.
4. Repetition Frequency
In this field enter the frequency at which the function will be repeated. You may enter from 0 Hz (DC) to 2.0 MHz
in 1 Hz steps. If a value of 0 Hz is entered, the function waveform clock is halted. A high going synchronization
pulse is given on the SYNC Out connector (front panel) at the start of the waveform. In Triggered mode, the
waveform is generated once per trigger event. The duration of each waveform will be 1/Repetition Freq.
NOTE: Very low rep rate frequencies, < 1 Hz, can be generated by setting the Repetition Frequency to 1 Hz. This
fills the waveform memory with 16,000 points of the desired function. Then go to Arbitrary Waveform Mode and
enter the Clock Frequency to obtain the desired function rep rate. Repetition Rate = Clock Frequency / 16,000
5. Level
In this field enter the loaded output level, from 4 mVp-p to 10 Vp-p in 1 mV steps. Into an open circuit, the
voltage swing will be twice the specified peak-to-peak value.
Waveforms with very narrow pulses may have signal energy above the cutoff of the output filter (10 MHz). The
resultant signal may have a distorted shape and reduced peak-to-peak output swing.
If the Pos Only? field is set to “Y”, and then the output level is halved, so that the output signal swings from 0V to
½ the specified level into a 50O load (or 0V to the specified level into an open circuit).
Offset
You can enter a DC offset voltage by pressing the Offset key. For more information see section 4.4.
Pulse Gen
Pos Only? N Duty Cycle: 50 %
Cont Rep Freq: 2,000,000.00 Hz 1,000 mV
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