. ITS A PAM HIGH FREQUENCY MODULATION . OF MY PRE CORCUIT NAMEMPDULATION AND DEMODULATION . HERE I REMOVED A PASSOVE DEVICE RELAY FOR SWITCHING AND USED A ACTIVE BJT SO THE CIRCUIT SIZE REDUCES. THE DEMODULATION PART REMAINS SAME as in my previous circuit in link
http://everycircuit.com/circuit/6160067240919040
