# QI COMM-Signal Simulation ltSpice

For a school project (Wireless Charging), I have to filter out and display the communication signal (2KHz) between transmitter and receiver from the Power Signal (100KHz). For this I have set up the circuit in ltSpice. I have created an ASK signal (product) as input to the MOSFET driver. Is it correct to select the ASK signal as the input signal? Should I put it on the SOURCE input of the mosfets. Unfortunately, I do not get the desired transmission signal on the receiver side. Can anyone help me?[![enter image description here]enter image description here

• Minor notes: unless you have specified Rser on the voltage sources, the parallel caps do nothing. At any rate, it's better to specify them as parasitics (e.g. Rser=10m Cpar=10u). Paralel caps could also be simplifed in only one equivalent. D1 and D2 seem to not have a .model associated, it would be better to specify at least some .model d d ron=1 vfwd=0.7 epsilon=50m revepsilon=10m (for ideal diode) or .model d d cjo=1p (for quasi-real). As for why isn't it working, do you know you can trust those TPS? If you test them separately, do you get wat you expect? – a concerned citizen Apr 9 '18 at 14:44
• And, no, the PWM input should be used for PWM signals, not direct modulated signals. That's up to you to provide. Where did you get the schematic from? Or do you have a reference? – a concerned citizen Apr 9 '18 at 14:46
• Thank you for your prompt reply. The circuit I have designed myself, unfortunately have no reference. How can I then model a communication signal? Where should I place the ASK signal. – Luigi Apr 9 '18 at 15:00
• It seems to me that, in your question, the requirements are simply filtering out the carrier from the signal. Maybe you're looking in a different direction? After all, you only need the input ASK signal, and some filtering method (part of which I see at the end of your schematic). At the bare minimum you'd need a rectifier and a lowpass filter. What rectifier, what filter, what possible other things, it's a mystery. – a concerned citizen Apr 9 '18 at 18:41
• Yes something like that. I would like to generate an ASK signal on the receiver side so that it looks on the transmitter side (L1) as in the above picture (ie a modeled signal) How do I generate such a signal using the mosfets – Luigi Apr 9 '18 at 20:53