Progenitor & Webmaster

Kirt Blattenberger

BSEE

KB3UON

EIEIO

**Carpe Diem!**

(Seize the Day!)

**5th MOB**:

My USAF radar shop

**Airplanes and Rockets**:

My personal hobby website

**Equine Kingdom**:

My daughter Sally's horse riding website

Q. Why won't the VSWR checkbox, row hide/show, and other special functions work?

A. Macros must be enabled for the functions to work. To enable macros, go to the "Tools/Macros/Security..." menu selections. Choose either the Medium or Low security option. Close the workbook and then re-open it. If you selected Medium security, a window will open during loading that asks if you want to enable macros - select Enable. If you selected Low security, the workbook will load without prompting you.

Q. How is dynamic range calculated versus linear gain , noise figure, noise power, etc?

A. Both the “Gain” and “P[sig]” columns are calculated based on a linear small signal
model and assume no power limitations. Similarly, all other parameters except “P_{SAT},” and “DR” are
based on linear models, since the standard cascade formulas are set up that way. Operation into the nonlinear
region negates the formulas. However, if a situation exists whereby the output power would exceed the P_{SAT}
of a stage, then a red “S” is placed in the “!!!” column as an alert to the user.

A separate calculation is provided for P_{SAT} to permit the user to keep a
tab on power in the system, and to estimate the dynamic range. P_{SAT}, as implemented in this
spreadsheet, is a step transition from the linear region to saturated output power, since attempting to accurately
model the transition region is beyond the capability of a simple spreadsheet. P_{SAT} for each stage is
calculated based on P_{SAT}
of the previous stage (N-1) and the gain, input power level and P_{SAT} of the current device (N) as
follows:

- Calculate what the output power would be for the current stage using the
calculated P
_{SAT}of the previous stage and the gain of the current device (ignoring actual P_{SAT}of the current device).

- If P’<= P
_{SAT}for the current device then P_{SAT}for the current stage is set to P’. - If P’ > P
_{SAT}for the current device, P_{SAT}for the current stage is set to P_{SAT}for the current device.

Noise power (P[n]) of each stage is calculated based on the noise power bandwidth of the device, the cumulative linear gain through the current stage, and the cumulative system NF through the current stage as follows:

Dynamic range for each stage is calculated as P_{SAT} – P[n], and does not
include a term for minimum signal-to-noise ratio as is sometimes used.

To reiterate, P_{SAT} is a subjective number whose optimal value is
determined by the user. Its function is to provide an indication of operation – advertently or inadvertently – in
the nonlinear range of the components, and to provide an estimate of the dynamic range that can be expected. More
powerful non-linear simulators such as Agilent’s “ADS,” Eagleware, or AWR’s “Microwave Office” are required to
obtain more exact results.

The DR Min/Max cells use the following equations, in keeping with the plan of using the worst possible combination of parameters:

- DR
_{MAX}= P[sat]_{MAX}– P[noise]_{MIN} - DR
_{MIN}= P[sat]_{MIN}– P[noise]_{MAX}