Data Sheet

LJ1269HC
Rev1.0 Page 57 Web: www.ljelect.com
Manchester encoding/decoding is thus made transparent for the user, who still provides/retrieves NRZ data to/from the FIFO
Figure 36. Manchester Encoding/Decoding
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.
Figure 37. Data Whitening
Sub GHz FSK/OOK Transceiver Module DATASHEET