Enraf Nonius 1600905, User Manual

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1600751-4D
Duty Cycle Modulation
Duty cycle can be described as the proportion between the duration of the pulse and the
duration of the interval. The duty cycle is expressed in a percentage (%). The device is working
in a continuous modus when the duty cycle is 100%.
Duty cycle modulation implies that the duty cycle fluctuates automatically in a flowing pattern.
The modulation is characterised by a fixed duration of a total of 12 seconds, during which time
the (pre) set duty cycle goes to 5% and back again. So, if the duty cycle is set at 50%, then it
will gradually drop to 55 in 6 seconds and then increase again from 5% to 50% in 6 seconds as
well. And so the modulation actually ensures that the pulse duration is automatically reduced or
increased.
Duty Cycle Modul ation with text 'example of the modulation when Duty Cycle is set at 50%’
Amplitude Modulation
Amplitude Modulation involves varying the ultra-sound intensity. This form of modulation is also
characterised by a rhythmic period of 12 seconds. The intensity (W/cm
2 ) is set at 100%. The
intensity will gradually drop from 100% to 85% in the first 6 seconds, after which it will increase
back up to 100% in the next 6 seconds.
Amplitude Modulation with text ‘example of the modulation wh en intensity is set at 1.0 W/cm 2
Both forms of modulation can be switched on and off independent of one another. This (de)
activation is achieved by selecting the desired function on the parameter display (see page 25).
The standard (factory) setting for both modulation forms i
s ‘modulation on’.
When both modulations are activated, they run synchronous (in phase) and they start ‘from high
to low’. The difference b
etween the minimum and the maximum level of the effective output is
the greatest in this way.
!

CAUTION:
StatUS-therapy, on the other hand, makes use of two special forms of modulation that ensure
that the peaks in intensity in the ultra-sound bundle are strongly reduced, diminishing the risk of
cavitation and preventing the occurrence of ‘hotspots’ .