Biological effects caused by a nanosecond pulse, such as cell membrane permeabilization, peripheral nerve excitation and cell blebbing, can be reduced or cancelled by applying another pulse of reversed polarity. Depending on the degree of cancellation, the pulse interval of these two pulses can be as long as dozens of microseconds. The cancellation effect diminishes as the pulse duration increases. To study the cancellation effect and potentially utilize it in electrotherapy, nanosecond bipolar pulse generators must be made available. An overview of the generators is given in this paper. A pulse forming line (PFL) that is matched at one end and shorted at the other end allows a bipolar pulse to be produced, but no delay can be inserted between the phases. Another generator employs a combination of a resistor, an inductor and a capacitor to form an RLC resonant circuit so that a bipolar pulse with a decaying magnitude can be generated. A third generator is a converter, which converts an existing unipolar pulse to a bipolar pulse. This is done by inserting an inductor in a transmission line. The first phase of the bipolar pulse is provided by the unipolar pulse's rising phase. The second phase is formed during the fall time of the unipolar pulse, when the inductor, which was previously charged during the flat part of the unipolar pulse, discharges its current to the load. The fourth type of generator uses multiple MOSFET switches stacked to turn on a pre-charged, bipolar RC network. This approach is the most flexible in that it can generate multiphasic pulses that have different amplitudes, delays, and durations. However, it may not be suitable for producing short nanosecond pulses (<100 ns), whereas the PFL approach and the RLC approach with gas switches are used for this range. Thus, each generator has its own advantages and applicable range.

通过施加另一个极性相反的脉冲，可以减少或消除由纳秒脉冲引起的生物效应，例如细胞膜通透性，周围神经兴奋和细胞起泡。根据消除的程度，这两个脉冲的脉冲间隔可能长达数十微秒。消除效果随着脉冲持续时间的增加而减小。为了研究消除效果并在电疗中潜在地使用它，必须提供纳秒级的双极脉冲发生器。本文概述了发电机。一端匹配而另一端短路的脉冲形成线（PFL）允许产生双极性脉冲，但是在相之间不能插入任何延迟。另一台发电机采用了电阻的组合，电感器和电容器形成RLC谐振电路，从而可以产生幅度衰减的双极性脉冲。第三发生器是转换器，其将现有的单极性脉冲转换为双极性脉冲。这是通过在传输线中插入电感器来完成的。双极性脉冲的第一阶段由单极性脉冲的上升阶段提供。第二阶段是在单极性脉冲的下降时间内形成的，此时，在单极性脉冲的平坦部分中预先充电的电感器会将其电流放电到负载。第四种类型的发电机使用堆叠的多个MOSFET开关来开启预充电的双极RC网络。这种方法最灵活，因为它可以生成具有不同幅度，延迟和持续时间的多相脉冲。然而，它可能不适合产生短的纳秒级脉冲（<100 ns），而PFL方法和带有气体开关的RLC方法则用于此范围。因此，每个发电机都有其自身的优势和适用范围。