Hi all,

I'm using ENA model# E5071B. My measurement freq. is from 750MHz to 950MHz with input power = -20dBm. DUT is a LNA.

Could anyone pls advise how can I use a ENA to measure IP1dB? Appreciate if you can let me know the measurement procedure step-by-step. Thanks!

I'm using ENA model# E5071B. My measurement freq. is from 750MHz to 950MHz with input power = -20dBm. DUT is a LNA.

Could anyone pls advise how can I use a ENA to measure IP1dB? Appreciate if you can let me know the measurement procedure step-by-step. Thanks!

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For the PNA-X, what is the gain reference for the P1dB point if there is gain expansion at lower power levels? Or does the user need to assure that the first data point can be used as a reference?

I sometimes work with higher power PAs that for efficiency/linearity tradeoff reasons may be biased so that the Po vs Pi at lower levels is not linear. I've written ael functions for 2D swept sims in ADS (or Goldengate) to compute compression points, and have written LabVIEW code to do 2D measured sweeps to do the same. I wondered how you've dealt with this.

Most common is deviation from linear gain. The power of the linear gain is specified, and the s21 measured at that power, then the power is increased until S21 deviates by the specified compression value (typically 1 dB).

A second method is Deviation from Maximum gain. During the 2-D sweep, the maximum gain is recorded and the compression is computed as the power above maximum gain that makes S21 deviation by 1 db from maximum gain.

A third method, based on a more traditional way of measuring, is called "backoff", where you look for 1 dB of compression with X dB backoff or change in power. Most common is looking for the point where a 10 dB change in power gives a 1 dB change in gain.

A fourth method, called X/Y, is really the same as backoff, but defined as X dB change in input power causes Y dB change in output power. Typically 10 dB change in input power causes 9 dB change in output power

Backoff and X/Y are probably the best methods to measure compression as they most relate to real world issues and have the least impact from noise and low level issues.

A fifth method, which isn't really compression at all, is call "backoff from saturation" and looks for the point X dB lower than the saturated gain, typically 0.03 dB lower. It's common in the satellite business.