| 摘要 |
<p>Medium frequency generator for electrotherapy comprises a sawtooth or delta oscillator (1) providing useful current for two or more electrode circuits. At least one of these currents is rhythmically variable in its phase position according to the low frequency voltage of a low frequency oscillator (3). The sawtooth or delta mf oscillator has an output frequency twice the mf to be applied to the pairs of electrodes (9, 10), and is connected via a single comparator (2), for comparing the oscillator output voltage (U1) with the low frequency voltage of the low frequency oscillator for pulse width modulation, and via two bistable trigger circuits (5, 6) to the two pairs of electrodes. In the cycle of the width-modulated pulses (U2) of the comparator, one trigger circuit (5) is switched over by the width of the modulated pulses with a time lag relative to the other (6).</p> |
