RF69 datasheet(60/81 Pages) ETC2

номер детали	RF69

подробное описание детали	Low Power Integrated UHF Transceiver with On-Chip 20dBm PA

PDF	81 Pages

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производитель	ETC2 [List of Unclassifed Manufacturers]

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RF69

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5.5.8.2. Data Whitening

Another technique called whitening or scrambling is widely used for randomizing the user data before radio transmission.

The data is whitened using a random sequence on the Tx side and de-whitened on the Rx side using the same sequence.

Comparing to Manchester technique it has the advantage of keeping NRZ data rate i.e. actual bit rate is not halved.

The whitening/de-whitening process is enabled if DcFree = 10. A 9-bit LFSR is used to generate a random sequence. The

payload and 2-byte CRC checksum is then XORed with this random sequence as shown below. The data is de-whitened

on the receiver side by XORing with the same random sequence.

Payload whitening/de-whitening is thus made transparent for the user, who still provides/retrieves NRZ data to/from the

FIFO.

L F S R P o l yn o m ia l = X 9 + X 5 + 1

X 8

X 7

X 6

X 5

X 4

X 3

X 2

X 1

X 0

T ra n s m it d a ta

W h ite n e d d at a

Figure 38. Data Whitening

Page 59

RF69 датащи(PDF) 60 Page - List of Unclassifed Manufacturers