When you choose "(2) Spline Fit" from the Main Menu, either by pressing "2," or by using the "F2" function key, you'll enter the Spline Fit Module. The screen display will look as follows:

       Spline Fit Module

       Enter Filename [<Enter>=Quit] ? _

Let's look at the summary of a data file that was placed in the mwsoft\sdata\mwdata6 sub-directory during the installation.
At the prompt above, type "NE02135A" for the bipolar transistor data file we have in the\mwdata6 sub-directory, and press <Enter>:

Data File Summary File  :  NE02135A ! Filename:                         NE02135A.S2P   VERSION: 1.0 ! NEC PART NUMBER:  NE02135               DATE:        1/83 ! BIAS CONDITIONS:      VCE = 10V.   IC = 5 MA # GHz S MA R 50 SData:   9 Freqs   FLo = 0.100   FHI = 4.000 ! NOISE DATA         2/81 NData:   7 Freqs   FLo  = 0.500   FHI = 3.500                                  Fmin = 1.200  Fmax = 3.700                                            - Press any Key -

A variety of useful information appears in the NEC Data File Summary on their low cost NE02135A device. For instance, you are shown both the s-data and noise header text, if they exist. This data often contains at least bias information. You can also see the number of data frequencies in the file. In this case, there are nine s-data frequencies over 0.1 to 4.0 GHz, and 7 noise frequencies over 0.5 to 3.5 GHz. Also, the min/max noise figure is given as 1.2 and 3.7 dB, respectively. If you wanted to add any other data of your own, you could use the SData+ File Utility to do so.

When you "- Press any Key -" as instructed above, you'll be given the option to view the input data file. You'll be asked:

       Display input file data (Y/N) [<Enter>=Quit] ? _

If you answer "Y" to the question above, here, except for the color, is what you'll see:

! FILENAME:        NE02135A.S2P  VERSION: 1.0 ! NEC PART NUMBER: NE02135       DATE:    1/83 ! BIAS CONDITIONS: VCE=10V, IC=5MA # GHZ S MA R 50 0.100    .84   -36    13.82  156    .02   73    0.94   -18 0.500    .68  -126     7.18  106    .08   35    0.51   -53 1.000    .66  -163     4.02   81    .09   27    0.34   -66 1.500    .65   178     2.75   64    .10   27    0.31   -74 2.000    .65   163     2.10   52    .12   30    0.31   -83 2.500    .66   151     1.68   39    .13   26    0.31   -95 3.000    .66   141     1.46   27    .14   26    0.33  -106 3.500    .67   129     1.24   17    .16   26    0.36  -116 4.000    .68   121     1.14    5    .17   23    0.38  -127 ! NOISE DATA     2/81 0.500    1.2    .36   69    0.14 1.000    1.5    .31  124    0.12 1.500    2.0    .50  165    0.05 2.000    2.4    .44 -175    0.06 2.500    2.6    .52 -161    0.10 3.000    3.6    .68 -141    0.14 3.500    3.7    .71 -139    0.21

If you just press <Enter>, you'll return to the Spline Fit Module opening prompt.

On the other hand, if you choose "N" up above and press <Enter>, you'll  be able to spline fit data in the file, and you'll see the following on-screen message.

       Spline fit S-data or Noise data (S/N) [<Enter>=Quit] ? _

Note: You're seeing the above message that refers to both s-data and noise data because the file NE02135A.S2P includes both types of data. If the file ONLY contained s-data, you would see:

       Spline fit S-data  (Y/N) [<Enter>=Quit] ? _

Or, if the file ONLY contained noise data, you would see:

       Spline fit Noise data  (Y/N) [<Enter>=Quit] ? _

O.K., we "diverted" a bit to pass along some information. Let's get back to where we were. We looked at the NE02135A input file, and then you were asked the question:

       Spline fit S-data or Noise data (S/N) [<Enter>=Quit] ? _

Type "S" (to spline fit s-data) in response to the above question and press <Enter>.

       Enter S-Data Output Freq Start, Stop, & Step ? _

If you remember from up above, the Data File Summary for the NE02135A device we listed above showed that it contained s-data over the frequency range of 0.100 to 4.000 GHz. Suppose we wanted to do a design for an amplifier working in L-Band over the range of 1 to 2 GHz? As it is, we only have s-data at three points, 1, 1.5, and 2 GHz. Our first cut design would likely be closer to optimum if we had better data. Let's spline fit data over 1 to 2 GHz in 0.1 GHz steps!

In response to the question above, about "Start, Stop, & Step," enter the following and press <Enter>.

       1,2,.1

Here is what you'll see:

Freq, S-Data Mag/Phase     1.000    0.660  -163     4.02    81    0.090    27    0.340   -66     1.100    0.661  -167     3.72    78    0.090    27    0.330   -67     1.200    0.659  -171     3.43    74    0.092    27    0.323   -69     1.300    0.656  -174     3.18    71    0.094    27    0.317   -71     1.400    0.653  -178     2.95    67    0.097    27    0.313   -72     1.500    0.650   178     2.75    64    0.100    27    0.310   -74     1.600    0.648   175     2.58    61    0.104    28    0.309   -76     1.700    0.647   171     2.44    59    0.108    28    0.309   -77     1.800    0.647   168     2.31    57    0.112    29    0.309   -79     1.900    0.648   166     2.20    54    0.116    30    0.310   -81     2.000    0.650   163     2.10    52    0.120    30    0.310   -83                                - Press any Key -

Please note that is the above on-screen display, there are three lines of s-data that are highlighted in bold print. These lines are highlighted because they represent real data; and they exist in the vendor s-data file; all the other lines are spline fit.

Note: At this point, you'll be asked "Print Logfile (Y/N) [<Enter>=No] ? _" Please press <Enter>.

If you choose the option to 'Print Logfile,' the data will be directed to 'Logfile.txt' within the \mwdata6 sub-directory, and not to the screen. Right-click on 'Logfile.txt' to print it, and then DELETE the file; it will re-create when next needed.

You'll next see:

       Write data to file (Y/N) [<Enter>=Quit] ? _

If you type "Y" and press <Enter>, you'll be asked to enter a filename for the data. Pick a name whose length is less than or equal eight characters, and press <Enter> once again. Only type a file NAME - do NOT add a three-letter extension! This data file will be saved in the c:\mwsoft\sdata\mwdata6 sub-directory. You'll be able to see it by choosing "Directory" from the "File Utility Menu."

If you respond to the "Write data" question with "N," or just <Enter>, you'll be returned to the Spline Fit Module opening prompt.