20 Chart Types
Block Diagram Icons
Hint / Help
Excel 2007 & Windows 2008 or newer.
Just leaked from the super-secret laboratories of RF Cafe are these screen shots of a new
cascade calculator code named "Wireless System Designer!"
For more than a decade, "RF Cascade Workbook
2005" has been the de facto standard for spreadsheet-based RF system cascade analysis. "Wireless
System Designer" is the next phase in the evolution. Detailed
information will be provided as the planned release date of June 1, 2017 gets nearer, but for now feast
your eyes upon these screen shots of what is to come. Following hundreds of hours of user interface,
formula, and VBA design, I am in the final testing and tweaking phase. Get your credit cards ready...
Sure, neither Keysight Technologies nor NI AWR have anything to worry about in terms of overall capability,
but "Wireless System Designer" does provide an alternative for users wanting to quickly assess system
parameters without a lot of set-up and special knowledge of software functionality. If you know how
to use Excel and you know anything about cascaded system calculations, then you know how to use "Wireless
Important Note: Because the price for Wireless System Designer is so low, I will
not provide any level of assistance with setup or operation. After all, you're getting an amazingly
feature-filled program for less than an hour of an engineer's billable time. Reported errors, if any,
will be addressed ASAP. I will be glad to entertain all questions about how your company can purchase
multiple licenses so that everyone is using Wireless System Designer legally ;-)
These instructions and screenshots were made in Excel 2007, so your screen and menu placements might
be a little different. I verified that everything works fine all the way through Excel 2016.
Mouse-over Comments for Cells
cell comment feature is use extensively to provide guidance for Wireless System Designer (WSD). The
contents of all the hints - and more - can be found on the Help worksheet (click the tab). The Help
worksheet, cell mouse-over comments, and this web page comprise the totality of documentation for Wireless
System Designer. There is no separate document available. Combined, there is a lot of information about
not just how to use WSD, but also how cascaded system analysis works. RFCafe.com is also chock full
of related information, so one way or the other, you're covered.
Locked vs. Unlocked Cells and VBA Code
built-in ability of locking cells to prevent unintentional overwriting of formulas is used in Wireless
System Designer. Most of the time the protection can be left on. Trust me, even after becoming famipar
with use, you will still find yourself accidently attempting to type into formula cells, and of course
doing so invalidates calculated results. Probably the only time you will need to remove protection is
when inserting or deleting columns or rows. Be sure to reapply protection when you are through.
Use Excel's Protect Sheet and Unprotect Sheet commands to lock and unlock, respectively, the cells.
Use the Password provided in the e-mail sent to you with the file attached. I will be glad to provide
it to you again with a proof of purchase.
The Visual Basic for Applications (VBA) code is locked separately and cannot be unlocked since there
is never a need to do so.
Inserting and Deleting Columns
Please see this separate page with screen shots and directions showing how to
insert and delete columns.
Navigating the Worksheet
Since the complete worksheet occupies nearly 900 rows,
a convenient drop-down menu is provided to move up and down the page. Information necessary for the
navigation to function is in the cell behind the menu, so if you accidently overwrite the cells, navigation
no longer works (keep Protection turned on).
System Cascade Charts
Charts are pre-configured for
plotting all calculated cascade parameters. Auto-scaling of the axes is the default, but you can
change all aspects of the chart formats per Excel standard. Select chart to display using drop-down
These four top-level system parameters are used for
many calculations. Be sure to define them along with the individual stage component parameters.
Set Limits on Gain and Power Input Values
Set maximum values for stage component input parameters. These
values are used for Data Validation in the input parameter cells. This results in a limit where the
charts auto-scale, since entering a null value of, say +999 dBm for IP3 will render its affect
utterly unnoticeable by the system, the IP3 chart will auto-scale to +1000 dBm or more while the
IP3 level in your actual system might be a maximum of +50 dBm. The useful data would then pe crunched
almost entirely at the bottom 5% of the chart. Of course you can always go in and manually scale the
chart axis minimum and maximum values as desired if you do use +999 dBm as the null value. This
just keeps things reasonable in case you prefer to let the charts auto-scale. Besides, +100 dBm
is good enough in most instances.
Specify Lower and Upper Frequency Sweep Limits for Filter Calculations
Enter the lower and upper frequency range for calculating the
system response inclusive of filters and frequency conversion stages. 175 equally spaced frequency steps
are calculated for all stages. Depending on your system, you might want to do sweeps across the entire
input band of concern, then do narrower sweeps that will provide finer detail within your smaller filter
Note: the Lower frequency cannot be zero (0) because of the logarithmic
horizontal chart scale. The smallest value permitted is 10-12, which
is small enough to include 1 Hz even when the Upper frequency is 1 THz.
Every stage can contain a frequency-dependent component which
can be an actual filter or a model of the frequency response of an amplifier, cable, coupler, etc. WSD
checks to make sure all required inputs are present and alerts you if they are not. For example, if
you select a bandpass filter and do not enter a lower frequency or if you use a Chebyshev and do not
enter a ripple value (or if you enter invalid values, like lower frequency greater than upper frequency).
Frequency Translation (Mixers | Modulators) Specifications
As with the
filter specifications, every stage can have a frequency translation. That means there is no limit to
the number of frequency conversions your system can have, although from a practical standpoint you
will probably never have more than three. WSD checks to make sure all required inputs are present
and alerts you if they are not. For example, if you
Frequency-Dependent Power Levels
Frequency-dependent power levels based on filter responses
and frequency translations are calculated separately from the other system cascade calculations (NF,
IP2, IP3, etc.). Along with the filter response, all nominal stage component gains are included.
Results are plotted in the "Frequency Response" ("Signal Power vs. Frequency") chart. These
frequency-dependent gains and power levels are not used in any of other cascade
calculations (NF, IP2, IP3, etc.). Note that frequency and power levels presented this matrix are
actually calculated in cells below Row 540, but are done this way to conveniently place power levels
next to their associated frequencies while making data selection for the chart simpler (take my word
Posted May 24, 2017