You are asked to design a DSB$-$SC modulator to generate a modulated signal Acm$($t$)$ cos ct

with the carrier frequency fc $=300$ kHz $($c $=2$ $300,000).$ The following equipment is

available in the stockroom: $($i$)$ a sinewave generator of frequency $100$ kHz; $($ii$)$ a ring modulator;

$($iii$)$ a bandpass filter with adjustable center frequency with the tuning range of $100$ kHz to $500$

kHz$.$

$($a$)$ Show how you can generate the desired signal.

$($b$)$ Explain how to tune the bandpass filter.

$($c$)$ If the output of the modulator must be $400$m$($t$)$ cos ct$,$ what should be the amplifier gain

to be used on the input m$($t$)$ to obtain the desired modulator output signal amplitude?