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Cascade Analysis User Manual



Okay, so perhaps you’ve just pulled up the calculator for the first time, and the maze of options and entry boxes has left you a little dumbfounded. Or, perhaps, you just like reading user manuals. Either way, we’re glad you’re here reading all this stuff we put together. Believe it or not, the tool is quite easy to use, despite its myriad of entry boxes and drop-down menus. So let’s take a step-by-step look at how to get the analysis rolling.

1)

 
Start by choosing the number of stages. We’ve built our tool to handle from one to ten stages. After you put in a number, click the “Re-Do Columns” button to make the unwanted columns go away, or to make the extra wanted columns appear.
 
2)

 
Stage 1. Let’s start by filling in the information for input stage (we’ve assumed the input as Stage 1, with the system flowing left to right). All other stages work the same way, so once you’ve mastered one, you’ve mastered them all.
 
  a.
 
In the component row, pick the corresponding type from our drop down menu. This information is purely for your benefit and does not impact the calculation in any way.
 
  b.


 
Now comes the fun part. In the “Specified P1dB & IP3?” row, you get to choose EITHER “input” or “output” for that component. So go ahead and pick whichever is easier for you - if your component data sheet is specified in terms of output parameters, then pick “Output”. What could be easier? But be careful: this choice WILL most definitely affect the calculation of the cascaded P1dB and IP3.
 
  c.

 
The first component parameter we’ll need is the gain in dB. In keeping with standard conventions, use positive numbers to represent gain and negative numbers to represent loss. In other words, that 4 dB passive attenuator has a gain of “-4”.
 
  d.

 
Next comes the 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, our 4 dB attenuator from above has a noise figure of “4”.
 
  e.

 
Okay, here’s where we get fancy. Enter the 1 dB compression point in dBm that’s consistent with the specification choice. In other words, if you specified “Output” in Part (2a), you’d better put the output P1dB here, or else your results will be waaaaay off.
 
  f.


 
Now enter the IP3, also in dBm, and also consistent with the choice from Part (2a). Both the IP3 and P1dB must be specified with regards to the input or output. Unfortunately, you can’t use input for P1dB and output for IP3 in the same component. But let’s face it, who in their right mind would specify a data sheet in this manner?
 
3)

 
Repeat parts (2a) through (2f) for each component. Remember, you can pick either input or output specifications for each individual component. Every time you enter a number, you should see the results in the “System Analysis” section update themselves.
 
4)



 
When you are all done entering the numbers, your system analysis should be complete and ready for printing. However, if you’re not sure, you can always hit the “Calculate” button. Your analysis is presented in two ways: “Input Referred”, where P1dB and IP3 are referred to the input, and “Output Referred”, where the P1dB and IP3 are (you guessed it) referred to the output. The overall gain and noise figure are referred from left to right through the stages.
 
5) Other buttons that will do nifty things when you click on them:
 
  a.




 
RESET: This button will reset the number of displayed columns to five, and all stages except the first will have a gain and noise figure of 0 dB, and input P1dB and input IP3 of 100 dBm. We’ve chosen these levels somewhat arbitrarily, as we’ve assumed you’ll be working with power levels well below 100 dBm. If we’ve made a you-know-what in this assumption, let us know and we’ll change it to suit your needs! Upon RESET, the first column is set to a gain of 5 dB, a noise figure of 2 dB, an input P1dB of 10 dBm, and an input IP3 of 20 dBm. We put some real numbers here just so the system analysis area wouldn’t be filled with NaNs.
 
  b.
 
PRINT: This button does what it says, at least for all of the browsers we’ve tried. If you have any issues with printing let us know and we’ll take a look.
 
  c.



 
RE-DO COLUMNS: This button will allow you to change the number of components in your analysis. If you are going to a smaller number of components, the newly hidden columns will keep any data you’ve previously entered, but they will not affect the calculations. If you are moving to a larger number of columns, all previously entered data should remain in place. In both cases, the outputs will clear until you enter a new number in a field or hit the “Calculate” button.
 
And that’s all there is to it! Have fun, and if you see any problems or strange results, let us know.

Back to the Calculators Page      Cascade Analysis Calculator

 

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Phone: 978-467-4290
Fax: 978-467-4294

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Custom MMIC

300 Apollo Drive
Chelmsford, MA 01824
Phone: 978-467-4290
Fax: 978-467-4294

Terms and Conditions

©2006-2017 Custom MMIC
All rights reserved.