Question on UCODE 8 behavior under auxiliary CW interference during reader communication

Zhy889 — Wed, 17 Dec 2025 14:02:25 GMT

Dear NXP Technical Support Team,

I am currently conducting academic research on passive UHF RFID systems and would like to consult you regarding an observed behavior of the NXP UCODE 8 tag under a specific RF excitation condition.

In our experiments, during normal EPC Gen2 reader–tag communication, we introduce an additional continuous-wave (CW) signal at a different carrier frequency (no data information) from a USRP device. When the auxiliary CW has relatively high power, we observe that:

UCODE 8 tags fail to correctly decode reader commands and the communication breaks down.

In contrast, under the same experimental setup, Impinj Monza 4 tags can still maintain communication and, in some cases, show extended readable distance.

We understand that EPC Gen2 tags are designed for single-carrier operation and that auxiliary CW signals are outside standard operating assumptions. However, we are interested in understanding whether this difference may be related to implementation-level differences, such as:

a. RF front-end selectivity or matching bandwidth

b. Rectifier or envelope detector nonlinearity

c. Downlink demodulation architecture (e.g., envelope detection, filtering, timing recovery robustness)

d. On-chip filtering or interference suppression mechanisms

Our question is not about protocol compliance, but rather about whether UCODE 8 has known sensitivities to strong out-of-band CW signals, or if there are architectural characteristics that could explain the observed decoding failure compared to other Gen2 tags.

Any insight you could share at a high level (even without revealing proprietary details) would be greatly appreciated and very helpful for correctly interpreting our experimental results.

Thank you very much for your time and support.

NXP DesignsのトピックQuestion on UCODE 8 behavior under auxiliary CW interference during reader communication

Question on UCODE 8 behavior under auxiliary CW interference during reader communication