A number of researchers have reported that Rife/Bare, and pad units are more effective when the output is pulsed. In the case of the Bare unit, the pulser is placed between the audio generator and the CB. With pad units, the output is pulsed and the output of the pulser is connected to the pads. With the EMEM2 and EMEM3 units, the output of the 555 board can be pulsed before it gets to the Darlington transistor.
The circuit is fairly simple. The same PC board that is used for zappers and the EMEM2 and 3 frequency source can be used. The pot should be wired so that when it is fully counter-clockwise, the resistance is highest. As the pot is turned up, the frequency of the pulse will increase. The circuit was designed for a Bare unit which has 12 volts DC available. I am not sure yet how it will run on 9 volts.
Schematic for pulser circuit