NXP Semiconductors
AN11740
PN5180 Antenna design
AN11740
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Application note
COMPANY PUBLIC
Rev. 1.1 — 19 June 2018
345311
49 of 62
Table 2.
Most relevant analog test signals
Not specified in the data sheet
Parameter (hex)
Test signal
1
ADC signal: unfiltered Q channel
2
ADC signal: unfiltered I channel
3
ADC signal: filtered Q channel
4
ADC signal: unfiltered I channel
9
BPSK_SUM: BPSK demodulator output signal, indicating the phase shifts of
the modulated subcarrier (relevant only for BPSK)
4.6.2.1 Example Type B
The following figures show the relevant test signals under some standard test conditions.
The Fig 44 shows a standard type B response from a ReferencePICC. The left part starts
with falling edge of the trigger signal (blue) derived from the digital test signal using the
TX_ACTIVE.
The green signal shows the LMA input at the ReferencePICC. In the center of the
screenshot the first phase shift of the start of frame (SOF) can be seen.
The yellow signal shows the ADC output of the demodulated subcarrier (unfiltered Q
channel).
The orange signal shows the phase shifts, as detected by the PN5180.
The screenshot on the right-hand side of Fig 44 shows the same response with the same
test signals, but horizontally zoomed into a character of the type B response. Not only the
phase shifts can be seen, but also the phase noise (noise floor in the orange signal).
Depending on LMA level, coupling and noise from the PCD environment this noise might
be higher than shown in Fig 44, and then might impact the Rx performance.
Note:
All the data related to the shown signals in the Fig 44, Fig 45 and Fig 46 can be
received properly.
