8. Definitions and parameters
User Manual – PhysioGo.Lite Electro page 44 / 96
8. Definitions and parameters
Terminology
The carrier frequency is a parameter of medium frequency alternative current, the so called carrier wave
of interferential fourpolar and bipolar currents (4000 Hz), Kotz’ current (2500 Hz) and medium frequency unipolar
currents modulated by low frequency current. As the current carrier frequency increases, the capacitive
resistance of the tissues decreases.
Base frequency is a parameter of low frequency alternative current, which is produced in course of amplitude
modulation of carrier wave creating a low frequency sine curve (5÷100 Hz). The sine wave of base frequency
constitutes an envelope circumscribed on the carrier wave, which enables its deep penetration into human body
tissues, is often referred to as AMF – amplitude modulated frequency.
Basic frequency spectrum determines scope of modulation of this parameter as function of time. This parameter
determines the frequency added to basic frequency, and the sum of them is the highest base frequency value
that occurs during modulation.
Example: Base frequency is at 60 Hz, spectrum 40 Hz. That means that the base frequency will vary within
the limits 60 to 100 Hz (60+40=100) in timely dependence determined by the FM program.
The base frequency of Kotz’ current determines the number of bipolar “bursts” in the 2500 Hz carrier wave.
TENS pulse frequency determines frequency of occurring pulses, where the pulse duration time is a value set
separately between 25 and 300 µs.
Output signal modulations
Frequency modulation program FM determines how the frequency of the signal changes, depending on the
settings of the base frequency and the spectrum over a given time interval. Program parameters define:
• duration of the lowest frequency,
• time of increase to the highest frequency,
• duration of the highest frequency, and
• falling time to the lowest frequency.
If SPECTRUM value is set up at 0 Hz, it is not possible to use frequency modulation program. And when nonzero
SPECTRUM value is selected, default settings of frequency modulation program are 3 s rise time and 3 s fall time.
Amplitude modulation program AM determines in what time spans therapeutic signal amplitude change and
how deep that change goes. Such modulation aims at delaying process of adaptation to the set value of the
therapeutic signal and alleviation of adverse treatment results with patients badly tolerating electrotherapy.
Amplitude is modulated within the range 70% to 100% of set up output signal.
Training program controls occurrence of muscle contraction and rest phases. Voltage and amperage, which will
be applied during electrostimulation, should be determined when no training program is set. This program
includes an active phase only, enabling comfortable setup of appropriate value of output signal. This program
shall not be applied in therapy. Set value of output signal shall be remembered and set up during session
of the selected treatment program.
The programs which feature relatively long rest time in relation to contraction phase give appropriate conditions
for muscle fiber regeneration. The programs which have decisively shorter rest phase shall only be applied to
electro-gymnastics with healthy persons or to cause tonolitic effect.
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