I want to downconvert a simple 100kbit/s NRZ OOK/ASK signal from 900 MHz. In a previous design I found two options:
L1 and C1 are an L-match (input is 50 Ohm). The diodes are Schottky diodes (HSMS-285C). I recognize both options as an instance of an N-stage rectifier (option 1: one stage, option 2: two stages).
I simulate both options in LTspice and the output voltage of option 2 is twice as high as option 1 which sounds definitely better to me. I assume this would not increase the SNR (?) but it would make threshold detection of Vout easier when the voltage is larger.
- Why would I pick option 1 over option 2? Is there any advantage of using option 1?
- Why stop at 2 stages? Why not multiple stages? (I know that the voltage multiplication will be limited by the parasitics and the diode drops). But could there be a deeper reason why the original author used only one or two stages?