Choosing a High Linearithy RF Amplifier IC for QFDM/QAM64 Transmitter

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crackerboy

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Hi guys,

I want to design an UHF/VHF 5Watts RF amplifier for my project. Do you have an experimental idea for designing a "high linearity RF amplifier" for transmitting QAM signals?

I think this idea may need a strong knowledge about RF but i assume these days we may find single chip solutions because of the improved technology.

I found a **broken link removed** an amplifier. Is this suitable or any other suggestion?
 

This amplifier seems to work in A-AB class that is pretty linear.But before that, you should specify your linearity requirements with QAM modulation being as ACPR.
Because linearity is quite variable and depended requirement regarding to wanted one.I mean, some figure of linearity may be sufficient for some modulation scheme but the same linearity may not be osme of others..
 
Linear operation is possible if you set Vgg to 3.5V, maybe even 4V for very linear amplification.
And because 64QAM has about 7dB peak-to-average (and 16QAM about 4dB) might need to back-off few dB's the output power, to get minimum signal distortions and lowest ACPR.
 
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