DaveB wrote on Mar 24th, 2009, 4:00pm:ACPR and EVM are both system level performance requirements. You'll need to meet those regardless of whether you are using Quadrature/Polar/DDS transmitter designs.
It is very common.
But each modulation architecture have advantages and disadvantages.
As a simple example, if we realize a constant envelope modulation such as FSK, direct modulation of VCO is superior than I/Q modulation regarding EVM or modulation accracy.
If we use DDS to achieve high ACPR, I think DDS is not so superior regarding current consumption.
Predistitortion using I/Q modulator for improving ACPR is well known.
But how to improve ACPR using polar modulator ?
If we use Delta-Sigma modulation in polar modulation system. clock speed must be very fast.
So current consumption will be very large.
My question is :
How do you think of merit or demerit of polar modulation in achieving good ACPR and EVM compared to I/Q modulator ?
Especially if we will aim at multi-mode transmitter.