RF Cascade Workbook 2018™ v1.3

For more than a decade, RF Cascade Workbook 2005™ has been the de facto standard for spreadsheet-based RF system cascade analysis. RF Cascade Workbook 2018™ is the next phase in the evolution. Chances are you have never used a spreadsheet quite like this. If you know how to use Excel and you know anything about cascaded system calculations, then you know how to use RF Cascade Workbook 2018™ (formerly Wireless System Designer™). This is significantly easier and faster than using the multi-thousand dollar simulators when a quick system analysis is all that is needed. Hundreds of hours have gone into developing this tool. Please see RF Cascade Workbook 2018™ intro video below for an overview of features.

6/16/2020 Update to v1.3: Background image was changed.

5/19/2020 Update to v1.2: The minimum noise figure (NFmin) formula has been modified to prevent a negative value. Please send me an e-mail if you would like a replacement file. Instructions to make the change yourself can be seen here.

4/24/2020 Update to v1.1: The IP1dB formula was modified.

Feature Descriptions

Mouse-over Comments for Cells

Excel's cell comment feature is use extensively to provide guidance for RF Cascade Workbook 2018™ (RFCW). The contents of all the hints - and more - can be found on the "Help" worksheet (click the tab at the bottom). The "Help" worksheet, cell mouse-over comments, and this web page comprise the totality of documentation for RF Cascade Workbook 2018™. There is no separate document available. RF Cascade Workbook 2005™ User's Guide should also be useful since it extensively documents formulas. Combined, there is a lot of information about not just how to use RFCW, but also how cascaded system analysis works. RF Cafe is also chock full of related information, so one way or the other, you're covered.

Locked vs. Unlocked Cells and VBA Code

The built-in ability of locking cells to prevent unintentional overwriting of formulas is used in RF Cascade Workbook 2018™. Most of the time the protection can be left on. Trust me, even after becoming familiar 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. I recommend never Unprotecting any worksheet since doing so invalidates the integrity as provided. Be sure to reapply Protection if you decide to Unprotect. See the RFCW Terms of Use information about liability.

Protecting & Unprotecting the Worksheet

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.

When Protecting the worksheet, be sure to select ALL the check boxes in order to ensure that the macros will run (click thumbnail above). You might need to scroll down in the window to access all the check boxes. See Worksheet Protection information on the RFCW "Help" page.

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).

Hiding and Unhiding Columns

Rather than deleting and/or adding component stage columns, it is much simpler to Hide and/or Unhide columns. Doing so retains all the information without having to go through all the steps needed for deleting and/or adding columns. All the input and calculated is retained and included in the overall output, but the Hidden stage columns are not included in the charts. Hiding component stage columns can be a good way to exclude unneeded plots from the charts without requiring you to delete/add data series - which is itself a pain to do.

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 menu.

System-Level Parameters

These four top-level overall system parameters are used for many calculations. Be sure to define them along with the individual stage component parameters.

Build System Block Diagram

Build your system block diagram using the provided images or make your own. Click on the "Icons" tab at the bottom of the page to access and copy the desired icon (58x32 pixels), then paste it into the block diagram. Use Excel's standard Objects alignment and spacing tools for a perfect layout.

Specify Component Parameters

Enter each stage's nominal and tolerance values. Error checking is provided for exceeding power or gain limits (see below), no negative noise figure (NF), making sure NF is equal to absolute value of a negative gain component, etc. Errors are reported in the "Status" cells. Two rows f user-defined cells are provided for formulas along with a "User Defined" chart that displays the cell data.

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 be 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 bandwidths.

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.

Filter Specifications

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. RFCW 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. RFCW checks to make sure all required inputs are present and alerts you if they are not.

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 for it).

RF Cascade Workbook 2018™ Intro Video (part 1)

RF Cascade Workbook 2018™ Intro Video (part 2)

For archival purposes only, here are links to previous versions of RF Cascade Workbook:

RF Cascade Workbook 2002

RF Cascade Workbook 2003 (includes user guide)

RF Cascade Workbook 2004 (includes user guide)

RF Cascade Workbook 2005 (includes user guide)

6/16/2020 Update to v1.3

The background image was changed to a muted log-log graph pattern.

You can change the background image to anything you like, or have no background image at all. To do so, go to Page Layout -> Delete Background. To add a background, do Page Layout -> Background and select a file.

5/19/2020 Update to v1.2:

The Minimum Noise Figure calculation has been modified to prevent negative number.

If you already have data entered into a file, you might prefer to edit that file rather than copy the data it into a new v1.20 file. If you are comfortable with editing both the spreadsheet cell equations and Visual Basic code, the instructions below and screen shots at the right show you how to do it.

1. Click in cell F108 and replace the existing equation with this one:
   
   =IF(F35-F36<0,0,F35-F36)
   
2. This is how to modify the VBA code:
   1. Click on the "Developer" tab.
   2. Click on the "Visual Basic" toolbar button.
   3. In the tree page, double-click on "CascadeParameters" under the "Modules" branch.
   4. Add the following equation to the end of the "Function CascadeNF" function:
      
      If CascadeNF < 0 Then
      CascadeNF = 0
      End If
      
      Click on "File->Save."
   5. Save the entire workbook file to preserve the changes.

4/24/2020 Update to v1.1:

IP1dB Formula Correction Instructions

You might prefer to just change the IP1dB formula cells rather than copy all the information from an existing workbook into the new version. If so, these instructions provide a simple way to do it. Screen captures of each step are in the image to the right (click for a larger version).

1. Click in cell F45 and change the formula from
   
   =F43-F33-1 to
   =F43-(F33-1) , or to
   
   =F43-F33+1 ,
   
   then press Enter.
2. Click in cell F45 and select Copy.
3. Highlight cells H45 through AE45.
4. Select Paste Special... then select Formulas and press OK.
5. Click in one of the IP1dB cells in row 45 and verify that it contains the new formula.
6. Save your workbook.

Posted June 16, 2018