AX8052F131 datasheet(35/46 Pages) ONSEMI

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Transmitter

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AX8052F131

6.2. RF Input and Output Stage (ANTP/ANTN)

The AX8052F131 uses fully differential antenna pins.

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

AX5031_TXPWR. Output power as well as harmonic content will depend on the external

impedance seen by the PA, recommendations are given in section 7.1: Antenna Interface Circuitry.

6.3. Encoder

The encoder is located between the Framing Unit and the Modulator. It can optionally transform

the bit-stream in the following ways:

•

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.

The encoder is programmed using the register

AX5031_ENCODING, details and

recommendations on usage are given in the AX5031 Programming Manual.

AX8052F131 Datasheet(PDF) 35 Page - ON Semiconductor