Problem with amplifier behind a SAW filter

I have circuit with an 50ohm amplifier behind a SAW filter.but the signal out from the amplifier has big second and third harmonics.why?

The input signal of the amplifier may be close to the compression point of the amplifier. Then the level increases of the amplifier harmonics.

yeah , this is the only reason , the input is high enough to make the amplfier near nonlinear region

khouly

No.I measure the signal input to the amplifer small enough.the saw has 20db IL,70MHz.

what is the 1 dB comp point of this amp ?

and , what is the extact input power in this case

khouly

amp output 1db point is 10dbm,Gain is 20db.but the signal output from the SAW is -20dbm.the signal from the SAW is ok.

mmm , yeah , ur far from the 1 dB compression , even if thr 1 dB point is the input is -10 dBm , i have assumed that the 10dBm is at output

how much attenutaion between the 2nd and the fundametal ?

khouly

maybe 10db

10 dB between ur fundamental and the 2nd harmonic

ur harmonics is quit high

try to put the SAW after the amp

khouly

signal from the saw has no 2nd harm..it is only from the amp.

yeah , i know , i meant to use th saw after the amp , coz the saw will attenuate the 2nd harmonic

khouly