CDA EVM9 Manual do Utilizador descarregar pdf (Página 20)

There are also new or more complex considerations

for 8PSK and EGPRS:

• (TX) Amplifier linearity, efficiency - thermal/battery again, but

this time MUCH worse

• (TX) Modulation Quality – EVM/Phase error/Frequency error

• (TX) Filter changes between GMSK and 8PSK,

but (almost same) ORFS emission mask

• (RX) Receiver must now demodulate both GMSK and 8PSK,

perhaps in contiguous bursts – 8PSK S/N - BER/BLER

demodulation challenges

EGPRS design considerations (RF)

1. Linearity of modulation (GSM/GPRS)

• how do we preserve phase and amplitude

information when radio components (e.g. power

amplifiers) introduce distortions of their own?

• GSM transmitters have been optimised to deliver

‘high’ efficiency and low noise at low cost

EGPRS design considerations (Modulation)

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CDA EVM9 Manual do Utilizador Página 20