As we know, we like to utilize the power amplifier
in non-linear/saturation region for its maximum
power efficiency.
We also know that only
constant envelope modulation scheme can use non-linear
power amplifier.
So my questions are:
1. Are basic form of BPSK and QPSK (without
pulse shaping) considered constant envelope modulations?
2. If they are constant envelope modulation
schemes, we can employ a non-linear power amplifier.
Knowing that besides amplitude distortion a
non-linear amplifier can introduce, it can also
produce phase distortion on the output signal.
So for PSK modulation where information is modulated
in the phase, won't a non-linear amplifier distorts
the phase and hence information?
Pls help
solve my confusion.
Tee