referring to fig1 a waveform intensity control circuit 2 , a display multiplex controller 4 , a charge pump 6 , and beam current control circuit 8 are included in a waveform display system . charge pump circuit 6 itself is well known prior art . waveform intensity control circuit 2 , commonly known as a z - axis amplifier , generates an analog control signal to determine the intensity of the displayed waveform . display multiplex controller 4 controls switching of various display modes . a waveform / readout signal is one output of display multiplex controller 4 . this is a control signal applied to the rest ( not shown ) of the waveform display system to switch the display mode between waveform and readout in such a manner that the crt beam is directed to the waveform while the signal is at a high state and the beam is diverted to readout display locations while the signal is at a low state . the waveform / readout signal is usually at the high state when the waveform is to be traced . however , in the above - mentioned cases in which readout display refreshing is required in the waveform tracing period , the waveform / readout signal periodically goes negative to refresh one dot of alphanumeric display each time . charge pump circuit 6 receives the waveform / readout signal and generates current pulses to be added to the waveform intensity control signal from waveform intensity control circuit 2 each time the display is switched from the readout display to the waveform display mode . the composite waveform intensity signal or the compensation waveform intensity signal is applied to beam current conrol circuit 8 to increase the crt beam current immediately following the refreshing of each dot in a readout display . thus , apparent intensity modulation of the waveform display caused by interruptions of the waveform is reduced . fig2 shows one embodiment of the multiplexed interference compensator in accordance with the present invention . waveform intensity control circuit 2 is represented by a potentiometer 10 operating between ground and a suitable positive voltage . charge pump circuit 6a comprises resistor 12a , diode 14a and capacitor 16a . one end of capacitor 16a receives the waveform / readout signal output , and the other end thereof is connected to one end of resistor 12a and the anode of diode 14a . the other end of resistor 12a is grounded and the cathode of diode 14a acts as an output terminal of charge pump circuit 6a . the output of charge pump circuit 6a is a current pulse generated each time the waveform / readout signal changes from the low state to the high state . capacitor 16a and resistor 12a in charge pump circuit 6a are chosen to maintain the average crt beam current directed to the waveform display , taking the secondary display diversion time , the waveform / readout signal amplitude , and the waveform intensity control level into account . the desired relationships can be maintained with various settings of the waveform intensity conrol circuit 2 by an appropriately non - linear transfer function in beam current control circuit 8 or by adjusting the return voltage of resistor 12 , the amplitude of the waveform / readout signal or other equivalent means . alternatively , optional jumpers 18a and 18b may be utilized to connect a voltage divider 20 into the circuit in series between the waveform intensity control circuit 2 and the junction of diode 14a and capacitor 16a to vary the fraction of the waveform / readout signal effectively applied to the charge pump 6a according to the setting of the waveform intensity control setting such that the effect of the current pulses can be made approximately proportional to the crt beam current at all settings . referring now to fig3 there is shown another embodiment of the multiplexed display interference compensator in accordance with the present invention . this is similar to the configuration of the embodiment shown in fig2 except that another type of charge pump circuit 6b is used . in charge pump circuit 6b , one end of capacitor 16b receives the waveform / readout signal and the other end of capacitor 16b is connected to cathode of diode 14b and one end of resistor 12b . the anode of diode 14b is grounded and the other end of resistor 12b acts as an output terminal of charge pump circuit 16b . similarly , charge pump circuit 6b generates a current pulse each time the waveform / readout signal changes from the low state to the high state to produce a composite waveform intensity signal , thus minimizing the apparent intensity modulation of the waveform . according to the present invention , the waveform intensity modulation due to interruptions of the waveform is effectively minimized to improve display quality . the multiplexed display compensator is very simple and easily applicable to an existing waveform display system . while there has been shown and described the preferred embodiments of the present invention , it will be apparent to those skilled in the are that many changes and modifications can be made without departing from the spirit of the present invention . consequently , the scope of this invention should be interpreted only by the appended claims .