Cascade Analysis Calculator (Active / Passive)

    Enter gain, noise figure, P1dB, and IP3 to calculate cascaded system performance.
    Note: P1dB and IP3 should be referenced to the output of each stage.



    ParameterInput ReferredOutput
    Gain (dB)
    NF (dB)
    P1dB (dBm)
    IP3 (dBm)

    Formulas Used

    • Total Gain (dB):
      \[ Gain_1 + Gain_2 + Gain_3 + [....] \]
    • Total NF (dB):
      \[ 10\log_{10}\left( nf_1 + \frac{(nf_2-1)}{Gain_1} + \frac{(nf_3-1)}{Gain_1Gain_2} + [....] \right) \]
    • Total P1(dB):
      \[ 10\log_{10}\left[ \left( \frac{1}{P1dB_1Gain_2Gain_3} + \frac{1}{P1dB_2Gain_3} + \frac{1}{P1dB_3} \right)^{-1} \right] \]
    • Cascaded Output IP3:
    • \[ OiP3_C = \frac{1}{ \frac{1}{IP3_{N-1} \cdot G_N} + \frac{1}{IP3_N} } [mW] \]
      \[ IP3_C = 10 \cdot log \left({IP3_C}\right) [dBm] \]
      • C = cumulative up to and including stage N
      • N = current stage
      • N -1 = previous stage
      • G = Gain

    Note: The calculations for Total P1dB and NF use linear values

    Cascade Analysis Calculator User Instructions

    This RF/microwave system Cascade Analysis Calculator is an easy to use design analysis tool. But it does have a few entry boxes and drop-down menus that can take some time to familiarize yourself with. So, let’s take a step-by-step look at how to get your cascade analysis rolling.

    1. Start by choosing the number of stages. (Stage 1 = input stage and you can presume the system flows left to right.)
    2. Pick the corresponding component type from the drop-down menu. (This information is purely for your convenience and does not impact the calculation in any way.)
    3. The next parameter required is gain in dB. In keeping with standard conventions, use positive numbers to represent gain and negative numbers to represent loss. As an example, a 4 dB passive attenuator has a gain of -4.
    4. Next is noise figure, also in dB. By convention, this should always be a positive number, where the noise figure of a passive component is generally the opposite of its loss. Thus, the 4 dB passive attenuator above has a noise figure of 4.
    5. Finally, is IP3, which is also in dBm, and to be consistent with the choice in step 3.
    6. Now move through each stage. Every time you enter a number, you will see the results in the "Output" section self-update.
    7. When you’re done entering data, your system cascade analysis will be complete and ready for printing.
    8. To start over, hit "Clear Values". This button will remove the values you entered from all stages.

    Note: Pressing <Enter> will change field values from those entered. Use the Mouse to click into each field to enter new values. The calculation will be updated after each entry.


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