Proxmark3 community

roteno

Member

Registered: 2010-03-05

Posts: 5

Proxmark3 RX Path

Can someone let me know if I have a proper understanding of how the Proxmark3 analog RX path works?

When the PM3 is acting as a reader and it wants to demod the data sent to it via a real tag it uses the envelope detected and filtered signals LOPKD and HIPKD.

When the PM3 is acting as a tag and it wants to demod the data sent to it via a real reader it uses the envelope detected and filtered signals LOPKD and HIPKD.

When the PM3 is "sniffing" both a real reader and real tag it uses the direct  amplified signals LORAW and HIPKD.

Does that sound right to you guys? Trying to understand the HW better. 

Thanks for reading.

roteno

Member

Registered: 2010-03-05

Posts: 5

Re: Proxmark3 RX Path

(*Found a TYPO)

Can someone let me know if I have a proper understanding of how the Proxmark3 analog RX path works?

When the PM3 is acting as a reader and it wants to demod the data sent to it via a real tag it uses the envelope detected and filtered signals LOPKD and HIPKD.

When the PM3 is acting as a tag and it wants to demod the data sent to it via a real reader it uses the envelope detected and filtered signals LOPKD and HIPKD.

When the PM3 is "sniffing" both a real reader and real tag it uses the direct  amplified signals LORAW and HIRAW.*

Does that sound right to you guys? Trying to understand the HW better.

Thanks for reading.

roteno

Member

Registered: 2010-03-05

Posts: 5

Re: Proxmark3 RX Path

Found my answer so I thought I would share:

The PM3 typically only uses the envelope detected signals LOPKD and HIPKD for all modes.

The squaring operation of the envelope detector translates the carrier to DC leaving the sub-carrier to be sampled and processed by the A/D and FPGA.
 
Thanks for reading.