ax5031 AXSEM, ax5031 Datasheet - Page 20

• Manufacturer Part Number: ax5031
• Description: Datasheet Ax5031
• Manufacturer: AXSEM

20
Circuit Description
5.6.
The
The PA drives the signal generated by the frequency generation subsystem out to the
differential antenna terminals. The output power of the PA is programmed via bits TXRNG[3:0]
in the register TXPWR. Output power as well as harmonic content will depend on the external
impedance seen by the PA, recommendations are given in the section 7: Application
Information.
5.7.
The encoder is located between the Framing Unit and the Modulator. It can optionally
transform the bit-stream in the following ways:
The encoder is programmed using the register ENCODING, details and recommendations on
usage are given in the
Version 1.3
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AX5031
RF Output Stage (ANTP/ANTN)
Encoder
It can invert the bit stream.
It can perform differential encoding. This means that a zero is transmitted as no
change in the level, and a one is transmitted as a change in the level. Differential
encoding is useful for PSK, because PSK transmissions can be received either as
transmitted or inverted, due to the uncertainty of the initial phase. Differential
encoding / decoding removes this uncertainty.
It can perform Manchester encoding. Manchester encoding ensures that the
modulation has no DC content and enough transitions (changes from 0 to 1 and from
1 to 0) for the demodulator bit timing recovery to function correctly, but does so at a
doubling of the data rate.
It can perform Spectral Shaping. Spectral Shaping removes DC content of the bit
stream, ensures transitions for the demodulator bit timing recovery, and makes sure
that the transmitted spectrum does not have discrete lines even if the transmitted
data is cyclic. It does so without adding additional bits, i.e. without changing the
data rate. Spectral Shaping uses a self synchronizing feedback shift register.
uses fully differential antenna pins.
AX5031
Programming Manual.
Datasheet AX5031