ATA559001-6DSY Atmel, ATA559001-6DSY Datasheet - Page 67

• Manufacturer Part Number: ATA559001-6DSY
• Description: RF Wireless Misc UHF (1k bit r/w anti-collision)
• Manufacturer: Atmel

Specifications of ATA559001-6DSY

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

9.2
9.3
9.3.1
4817C–RFID–03/07
Loop Function
Return Link Coding
Influence of the 2nd Symbol of the Return Header on the Modulation Stream
The synchronous return link supports a loop function. If the tag has transmitted all data and CRC
fields, the reader can start the loop function by sending a new header.
The reader is free to change any value of the return link header to optimize the link and its
quality.
Figure 9-3.
Note:
The second symbol of the return link header is used as a reference symbol which controls the
timing for the not–notch-locked modulation coding. The timing is stored in an internal register. If
a not-locked modulation coding type is selected, the IC compares the current time with
one-quarter and one-half of this stored value. Depending on the data, the modulation switches
between the notches.
Note:
When using 3phase1, the best solution will be to shift the changes to one-third and two-thirds of
the current length. Then the maximum baud rate can be achieved. During anticollision, this
length information is also used as a boundary length.
Only FM0 and 3phase1 support a bitwise modulation references. For the other coding structures,
the reader can use the modulation references of the return header.
This feature enables a dynamic sideband management to minimize noise effects or to optimize the
baud rate.
Types of Modulation in the Return Link
Notch-locked NRZI coding
Note: In the case of NRZI, the level depends on the status one bit earlier. The last sub-symbol
Soft-locked NRZI coding
Modulation During the Return Link
Bit stream
3phase1
(4th sub-symbol of the return header) is set to high.
FM0
0
1
0
0
1
ATA5590
1
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