pulse amplitude modulation

My neighbor passed away a few years back the person that took over his estate gave me this piece of equipment. I’m not sure what it is and what it is used for. jW

Hello, I'm not sure that I'm doing the PAM diagram correctly in LABVIEW. What I did is that I multiplied a Sine signal with a Square Signal and just filtered the signal. Attached are the circuit and results. Please let me know if something is wrong or missing.