BLOCKING READER: DESIGN AND IMPLEMENTATION OF A ...
BLOCKING READER: DESIGN AND IMPLEMENTATION OF A ...
BLOCKING READER: DESIGN AND IMPLEMENTATION OF A ...
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4.3.2.7 Frequency-Hopping Spread-Spectrum (FHSS)<br />
The FHSS signaling of the Reader shall comply on the FCC regulations. It shall<br />
comply on the RF envelope shown in the Figure 4.2. So it is important to consider<br />
these regulation in the reader design.<br />
4.3.3 Tag-to-Reader (T⇒R) communications<br />
4.3.3.1 Modulation<br />
- 3.3.2.3.<br />
Modulation shall be same as reader, as explained earlier in the sections 3.3.2.1<br />
4.3.3.2 Data encoding<br />
The backscattered data from the Tag shall be encoded by FM0 baseband or<br />
Miller modulation of a subcarrier at the data rate.<br />
• FM0 baseband:<br />
FM0 encoding or the bi-phase space is as shown in the Figure 4.5. The FM0<br />
basis functions showing the data-0 and data-1. And the FM0 generator state<br />
diagram labels, S1-S4, indicating four possible FM0-encoded symbols.<br />
• Miller-modulated subcarrier<br />
Miller encoding is as shown in the Figure 4.6. The FM0 basis functions showing<br />
the data-0 and data-1. And the FM0 generator state diagram labels, S1-S4,<br />
indicating four possible Miller-modulated subcarrier symbols. In this encoding<br />
the duty cycle of the symbols is measured at output and is between 45% to<br />
55%. A Miller encoding signaling shall end with a ”dummy” data-1 bit at the<br />
end of signal transmission.<br />
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