Quantum System and Channel User Manual

System and Channel Modes

Quantum Composers pulse generators have two levels of mode selection: system modes and channel modes.
Combining these two modes together allows for complex pulse trains to be generated by one unit. Most
Quantum Composers pulse generators contain both system and channel mode settings to provide the most
comprehensive pulse generation solution available.

System modes are generated by the unit and then distributed to each of the individual channels. The available
system modes are continuous, single shot, burst, and duty-cycle. Continuous mode generates a continuous
stream of pulses that begin by pressing the run/stop button (or a trigger input) and end when the run/stop
button is pressed a second time. Single shot mode will produce a single output pulse when the run/stop button is
pressed (or the unit is triggered) and the system will automatically disarm itself when the pulse is over. Burst
mode will generate a pre-determined number of pulses and then dis-arm the system when those pulses are
completed. Duty-cycle produces a number of “on” pulses followed by a number of “off” pulses, where both the
“on” and “off” pulses are set by the user. Figure 1 below shows a composite image of all of the available system
modes.

Figure 1

The channel modes are the same as the system modes with the exception of normal mode replacing
continuous mode. With the channel in normal mode the output will be whatever the system is set to. One of the
more significant changes at the channel level is that the channel will not re-arm itself. For example, with the
system set to normal and channel A set to single shot only a single pulse will be output of Channel A even though
the system is still armed and is actively generating pulses. The same behavior is exhibited when the channel
mode is set to burst. Once the number of defined bursts is reached the output will no longer generate pulses
even though the system is still armed and running. An easy way to think about the interaction between the two
modes is to think of it as the system feeds the channel. Whatever the system is set to goes to all of the channels
and the channels can then limit the output even further.

Figure 2 shows a pictorial representation of the system mode and its relationship to the channel modes. In this
figure the channel mode limits the output.

Figure 2

Figure 3 shows an example of where the system mode (Burst =3) limits the output as compared to Figure 2.

Figure 3

Notice that in figure 2, even though the channel burst mode is set to 5 only 3 pulses are output. A similar effect
is seen if the channel mode was set to duty-cycle.

The output will be generated off of the more restrictive of the two modes. If the system mode is set to
continuous and the channel mode is burst, only a burst of pulses will be generated, thus the output is limited by
the channel mode. If the system mode is set to burst and the channel mode is normal only a burst will be
generated but this time the output is limited by the system mode setting. While the output generated by the 2
examples above is the same (a burst of pulses) there are some minor differences.

In the first example where the system is set to continuous and the channel is set to burst the output set of
pulses will only occur once but the system run indicator will continue to flash. (Note: the system run indicator is a
flashing circle located in the upper left hand corner of the display) In this configuration, the channels can be re­armed by pressing the function (FUNC) button followed by the RUN/STOP button. With the system being set to
continuous and the channel being the limiter, one channel could be left at normal and a second channel could be
set to burst or single shot. This type of two stage architecture allows for the generation of complex pulse outputs
that other pulse generators cannot achieve.