Calculating 1dB compression point

Discussion in 'General Electronics Chat' started by RFeng, Jun 28, 2012.

  1. RFeng

    Thread Starter New Member

    May 30, 2012
    27
    0
    Hi,
    I got a PA design, and I'd like to see how the 1dB compression point (P1dB) depends on the Supply Voltage.
    i.e. Change the Supply Voltage from 0V to VDD, and calculate the P1dB per Supply Voltage value.

    An example graph:
    [​IMG]

    How can I calculate the 1dB Compression Point per Supply Voltage.
    Is there an efficient way to do it?

    (I'm working with Advanced Design System (ADS) if it matters).

    Thank you.
     
  2. RFeng

    Thread Starter New Member

    May 30, 2012
    27
    0
    Perhaps someone could help :)
     
  3. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    5,448
    782
    Use a curve fitting program for the graphical data.

    If I use the red marker data (roughly transcribed) I get various fit options. One case might be a natural logarithmic fit.

    Output_P1dB=31.2+9.7*ln(Vsn) [dBm]
     
  4. RFeng

    Thread Starter New Member

    May 30, 2012
    27
    0
    Hi,

    I meant how to can you "electrically" calculate by simulation 1dB compression point?

    The only way is to increase the input power and see when the Gain loses 1dB?
     
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