fo $=12$R$,.$C$.$ In R;$(2$Rs $+1)$Rz

C$=10$nF$,$ Fo$=4$Khz

The multiplexer is to enable two signals of the same frequency $($generated at $4$ kHz $)$ to be observed on a single channel of an oscilloscope. The unit is to handle signals of $5$ volts peak$-$to$-$peak, have a bandwidth of at least $10$ Hz $,$ to $100$ kHz and an input resistance of not less than $100k.$ The unit is to be powered from a normal laboratory stabilised power supply. The clarity of the display and ease of using the unit are most important. capacitor value $10nF,f_c$ is $4$ kHz $.$