If we drive PA output(3W class A rf power amp ) into saturation, is it have bad effect on rf fsk modulated signal? can we drive PA into saturation during normal operation to use its max power output?
LPF will give more IL if the order of the filter is more.
if the order is less then you will get less attenuation for the second harmonic.
BTW what is your specification on this?
BRF will be easy to implement if the freq is in GHz.
What's your Freq of operation?
IL of the order 0.4 dB should be ok. 0.6dB also fine if the amplifier takes care of this loss.
How ever IL is not the only parameter. In this case, it is associate with the rejection of the filter too.
What is the rejection requirement?
BRF is generally notch filter in this case.
Depend on the BW we need to go for multiple fingers.
I feel a 4 finger BRF will be sufficient.