**JRG-29**

March 22, 2005

**User's Manual for ITU-R Radar Emission Mask Spreadsheet**

**1. Introduction**

The ITU-R Emission Mask spreadsheet will plot the permitted emission
limits for primary radar stations operating in the radiodetermination
service as required in Appendix 3 of the Radio Regulations for spurious
emissions limits and the recommended out-of-band emission limits as
described in Recommendation ITU-R SM.1541 Annex 8. In addition, measured
emission spectrum data can be imported into the spreadsheet for
comparison with the ITU-R emission limits. The ITU-R Emission Mask
spreadsheet is in Microsoft Excel format.

A User's Manual for the spreadsheet is available by clicking on the
**HELP** button. For the **HELP** button to work, the associated
**HELP** file must be in the same folder as the Excel spreadsheet.

Comments and suggested improvements to the spreadsheet should be sent to
Robert Sole at <rsole@ntia.doc.gov>.

**2. System Requirements**

To run the ITU-R Emission Mask spreadsheet, your Personal Computer (PC)
must have Excel 2000 or later version, and your PC should have Windows
98 or later operating system.

**3. Opening Program**

Bring-up Microsoft Excel on your PC. Open the program ITU-R Emission
Mask. Enable the macros (you will be prompted to do this task). If not
prompted to enable macros, then go to the Tools pull down menu, select
Macro-Security. In the Security level tab, choose Medium and press OK.
Close the spreadsheet and re-open it. Upon re-opening the spreadsheet,
you should be prompted to enable Macros.

Click on the NEW/Restart button to initialize the spreadsheet.

**4. Importing Measured Emission Spectrum Data**

Measured emission spectrum data may be imported into the program[^1]. If
measured data is being used, it should be imported prior to providing
the data in Table 1 since the Excel program determines some parameters
in Table 2 from the measured emission spectra data. **If measured data
is not being imported, only ITU-R emission mask is being plotted, go to
Section 6.**

Sample emission spectrum data is available to validate the model. See
procedures below for importing sample measured data.

The imported emission spectrum data files must be in an ASCII coma,
space or tab delimited format; Easy Plot file format, or table entry.
For the ASCII format, the data must include the emission spectrum data
in two fields: 1) frequency in MHz, 2) measured emission spectrum data
in absolute power (e.g.; dBW or dBm), or in dB relative to the maximum
measured signal level. Note: if the data is in absolute power the
program will normalize the data to dB relative to the maximum measured
signal level.

The procedure for importing measured data into the spreadsheet is as
follows.

A.  Click on the **Get Data** button.

B.  A **Emission Spectrum Data** window will pop-up. Click on the
    **Read/Describe Emission Spectrum Data** button.

C.  A **Emission Spectrum Input** window will pop-up. Click on the
    **Read ASCII (CSV) File** button if the emission spectrum data is in
    an ASCII file. Click on the **Read EP File** button if the emission
    spectrum data is in an Easy Plot file. If the spectrum data is not
    in a file, and is available in a Table Entry form, click on **Table
    Entry**. If you want to import one of the sample data files, click
    on the sample aeronautical or maritime data button.

D.  An **Open Emission Spectrum Data File** window will pop-up. Go to
    the bottom of the menu and where it says "Files of type", use the
    pull-down menu to select "all files." Locate the file to be imported
    into the spreadsheet using the **Look in** pop-down button. Select
    the file to be imported, and click on **Open**.

E.  Click on the **OK** button in the **Open Emission Spectrum Input**
    window.

F.  A window will come on the screen that says **Emission Spectrum
    Data** with the ability to select fixed frequency or frequency
    hopping. Select the appropriate radar mode, fixed frequency or
    frequency hopping. If you select fixed frequency, window will
    display the Operating Frequency (F~O~) based on the measured data.
    If you select the Frequency Hopping Mode, the Lowest Channel
    Frequency (F~L~) and Highest Channel Frequency (F~H~) windows will
    display the selected F~L~ and F~H~ frequencies based on the measured
    data. In cases where there are multiple operating (fundamental)
    frequencies, or the radar is a frequency hopping radar, the program
    may not select the appropriate Operating Frequency (F~O~), or in the
    case of frequency hopping radar the Lowest Channel Frequency (F~L~)
    and Highest Channel Frequency (F~H~) for plotting the ITU-R emission
    mask. If the appropriate F~O~, F~L~ , or F~H~ values were not
    selected, type in the appropriate values. Then click the OK button.
    Measured data should now be visible on the Spread Sheet. The Excel
    program will normalize the power level at the fundamental frequency
    (F~O~) to 0 dB. Verify that the FO data in Row 6 of the spread sheet
    is in agreement with the plotted data. In the case of frequency
    hopping radars, the value for F~O~ in Row 6, should be midway
    between F~L~ and F~H~.

G.  If desired, the frequency scale of the measured data can be
    normalized to Zero MHz/GHz at the radar Fundamental Frequency
    (F~O~). Verify that the value to normalize the measured data to in
    Row 6 is correct. Click on the **Normalize to FO** button in Row 53.
    The measured data will be normalized to FO is zero Hertz.

**5. Changing Graph Title and X and Y Axis.**

Once the measured data has been imported into the spreadsheet, the
Titles and the X and Y axis range on the measured data plot can be
changed if necessary.

A. The graph titles, and X and Y axis titles can be changed by clicking
on the **Set Graphs Titles** button. Make appropriate changes to the
titles, and click on the **OK** button.

B.  The scale range of the X and Y axes can be changed if necessary by
    pointing the mouse to the X or Y scale on the graph and right click
    when the Values (X or Y) axis window pop-up. Then click on **Format
    Axis**. A **Format Axis** window will pop-up. Click on the **Scale**
    tab, and change the axis values as required. If you change the Y
    axis to a more negative number (e.g., -120 to -140) it will be
    necessary to also change the **Value the X axis crosses at** to
    -140. Then click on the **OK** button. The measured data should now
    be in the desired format.

**6. Importing ITU-R Emission Mask**

To develop and import the ITU-R emission mask for particular radar
characteristics follow the steps below.

**A. Peak Envelope Power and Measurement Bandwidth**

1\. Type in the radar Peak Envelope Power (PEP) in Row 7 of the
spreadsheet. The Pop-Down window to the right lets you select
appropriate units for specifying PEP. Click on the units then click on
the Pop-Down window to change the units.

> 2\. Type in the measurement bandwidth (B~m~) in Row 9 of the
> spreadsheet. The measurement bandwidth (B~m~) should be in the units
> of MHz.

**B. Table 1 -- Pulse/Sub-Pulse Characteristics**

Table 1 is provided to input the measured or calculated pulse/sub-pulse
characteristics for determining the ITU-R emission mask limits. The
definition of the radar parameters in Table 1 are provided in
Recommendation SM.1541, Annex 8. Table 2 shows the calculated ITU-R
emission mask parameters and other data needed for emission mask and
measured data correction factors for the radar parameters entered in
Table 1.

The Table 1 spread sheet will let you specify up to eight
pulse/sub-pulse time waveform characteristics for multiple waveform
radars. For multiple waveform radars, the ITU-R emission mask limits are
determined from the pulse type (waveform) which results in the maximum
B~-40~ dB bandwidth (see Recommendation ITU-R SM.1541, Section 3.1).

Use the following procedure for providing the pulse/sub-pulse waveform
information in Table 1.

A. The column labeled **Pulse Type** must have a value selected. Place
the cursor at the small red triangle on the upper right side of the cell
for guidance on selecting the proper pulse type. There are nine
pulse/waveform modulation types to choose from. Type in the appropriate
number. Once the pulse type is determined, fields in Table 1 that are
not applicable to that pulse type will have an NA in them.

B. The column labeled **Pulse Width** **or Sub-Pulse Width** (t) must
have data entered into it for the pulse width in microseconds. Place the
cursor on the small red triangle on the upper right side for guidance
for determining the pulse width.

C. The column labeled **Pulse Rise/Fall Time** (t~r~) must have data
entered into it for the rise time in microseconds. Place the cursor on
the small red triangle on the upper right side for guidance for
determining the pulse rise time.

D. For frequency swept (chirped) pulses, the column labeled **Chirp
Bandwidth** (B~c~) must have data entered into it for the chirp range in
MHz. Place the cursor on the small red triangle on the upper right side
for guidance for determining the chirp bandwidth.

E. For CW radars, the column labeled **Total Frequency Deviation**
(B~d~) must have data entered into it for the frequency deviation range
in MHz. Place the cursor on the small red triangle on the upper right
side for guidance for determining the frequency deviation.

F. For phase coded pulses, the column labeled **Number of Chips per
Pulse** (N) must have data entered into it for the total number of chips
per pulse. Place the cursor on the small red triangle on the upper right
side for guidance for determining the number of chips.

G. For frequency hoping radars, the columns labeled **Lowest Channel and
Highest Channel Frequency** (F~L~ and F~H~) must have data entered into
it for the lowest and highest channel frequency of a frequency hopping
radar deviation in MHz. Place the cursor on the small red triangle on
the upper right side for guidance for determining the frequency
deviation.

After the radar characteristics data has been completed in Table 1, the
calculated parameters related to the ITU-R Emission Limits Mask, and
measured data correction factors are shown in Row 1 of Table 2.

**7. Plotting ITU-R Emission Mask**

Review the calculated parameters related to the ITU-R Emission Limits
Mask data, and measured data correction factors shown in Table 2. The
ITU-R Emission Mask can be plotted on the measured data using the
following procedure.

A.  The emission mask data that will be plotted over the measured data
    corresponds to the Emission Mask Number shown in Column A of
    Table 2. If the radar mode has multiple pulse waveforms, review the
    B(-40 dB) bandwidths shown in Table 2 for the various pulse
    waveforms. Check the mask number shown in Row 38. If necessary,
    change the mask number in Row 38 to corresponds to the Emission Mask
    number in Column A of Table 2, which has the maximum B(-40 dB)
    bandwidth. Click on the **Add/Del Mask** button shown in Row 40. The
    emission mask will be added in the plot.

B. To delete the emission mask from the plot, click on the **Add/Del
Mask** button shown in Row 40. Check the mask number shown in Row 38. If
necessary, change the mask number in Row 38 to corresponds to the
Emission Mask number that you want to delete shown in Column A of Table
2.

C. To plot a second mask on top of the existing mask with a different
slope (dB/decade) from the B(-40 dB) bandwidth, click the appropriate
Waveform number in **TABLE 1** and then click on the **Copy Row**
button**.** A new row with data will appear in tables 1 and 2. Change
**Slope (db/decade)** field in **Table 2** to the desired value. Check
the mask number shown in Row 38. If necessary, change the mask number in
Row 38 to correspond to the Emission Mask number that you want to change
the slope of shown Table 2. Click on the **Add/Del Mask** button shown
in Row 40. The second emission mask will be added in the plot.

**8. ITU-R Mask Offset**

Recommendation ITU-R SM.1541, Section 4, states that B ~-40~ dB
bandwidth can be offset from the frequency of maximum emission level and
can be shifted to center the mask at the measured -40 dB level of the
measured data. If there is a ITU-R Mask on the Graph, click on the
**Add/Del Mask** button. This will delete the indicated mask. To offset
the ITU-R mask, click on the **Mask Offset** button and type in the
desired frequency shift in a positive or negative direction. Then click
on the **Add/Del Mask** button. The shifted ITU-R emission mask should
appear, and the OOB/Spurious Domain Intercept Frequencies in Table 2
should be changed by the amount of frequency shift.

**9. Plotting Additional Emission Masks**

Additional emission masks with parameters other than the ITU-R Emission
Mask can be plotted on the measured data. To plot additional emission
masks to the data plot, it is necessary to provide additional Pulse/Sub
pulse characteristics data in another row of Table 1. This can be
accomplished by clicking on the row in Table 1 that you want copied, and
then click the **Copy Row** button, rows 22-23. The RSEC Emission Mask
data will appear in the corresponding row in Table 2. Change the
appropriate parameter (e.g.; Slope dB/dec,) in the row of Table 2.
Change the Mask Number in Row 38 to the appropriate row of Table 2.
Click on the **Add/Del** button shown in Row 40. The additional emission
mask will be added in the plot.

**10. Printing of Spreadsheet**

To print Table 1, Table 2, and the graph click on the **Summary** button
on line 3 (Note: you must click on the **Summary** button on line 3 to
import the data prior to clicking on the Summary tab at the bottom of
the page). From the **Summary** page, the spread sheet can be printed,
or copied to a text document.

**11. Viewing of Measurement Data and ITU-R Emission Mask Data**

To view the measurement data and ITU-R emission mask data, click on the
**Temp** tab at the bottom left of the excel screen.

**SAMPLE DATA 1**

**Aeronautical Radionavigation Radar**

  --------------- -------------------------- -----------------------------
  **F~0~**        2844.4                     MHz

  **PEP**         1.300                      Megawatts

  **B~m~**        1                          MHz

                                             
  --------------- -------------------------- -----------------------------

**Table 1**

**Pulse/Sub-pulse Characteristics**

  ----------- ------------ --------- --------- ------------ --------- ----------- ----------- ------------------
  Waveform\   (t)\         (t~r~)\   (B~c~)\   (B~d~)\      (N)\      (F~L~)\     (F~H~)      Pulse Type
  Number      Pulse\       Pulse\    Chirp\    Total\       Number\   Lowest      Highest     
              Width or\    Rise/\    Band\     Frequency\   of\       Channel     Channel     
              Sub-Pulse\   Fall\     width\    Deviation    Chips\    Frequency   Frequency   
              Width\       time\     (MHz)                  Per Pulse (MHz)       (MHz)       
              (u sec)      (u sec)                                                            

  1           0.6          0.05      NA        NA           1         NA          NA          Non-FM pulsed
                                                                                              radars

  2           0.6          0.05      NA        NA           1         NA          NA          Non-FM pulsed
                                                                                              radars
  ----------- ------------ --------- --------- ------------ --------- ----------- ----------- ------------------

**Table 2**

**Calculated Results**

  ----------- ----------- ------------ ------------ ------------- ------------ ---------- -------------- ------------ ------------
  Emmision\   (B~s~)      (B~PEP~)\    (B~ref~)\    K\            B(-40)\      (S)\*\     RR Appendix 3\ OOB/\        Spurious\
  Mask\       Frequency   Required\    Reference\   Coefficient   Bandwidth\   Slope\     Spurious\      Spurious\    Domain\
  Number      Hopping     Bandwidth\   Bandwidth\                 (MHz)        (dB/dec)   Attenuation\   Domain\      Correction
              Range (MHz) to Measure\  (MHz)                                              (dB)           Intercept\   (dB)\
                          PEP (MHz)                                                                      Freq (MHz)   Mask /\
                                                                                                                      Data

  1           0           1.667        1.000        6.20          35.796       20.00      -60.00         2665.42\     -55.56\
                                                                                                         3023.38      0.

  2           0           1.667        1.000        6.20          35.796       40.00      -60.00         2787.80\     -55.56\
                                                                                                         2901.00      0.
  ----------- ----------- ------------ ------------ ------------- ------------ ---------- -------------- ------------ ------------

![](media/image1.wmf){width="8.552083333333334in"
height="4.989583333333333in"}

**SAMPLE DATA 2**

**Maritime Radionavigation Radar**

  --------------- --------------------------- ---------------------------
                                              

  **F~0~**        9406                        MHz

  **PEP**         12.000                      Kilowatts

  **B~m~**        1                           MHz
  --------------- --------------------------- ---------------------------

> **Table 1**

**Pulse/Sub-pulse Characteristics**

  ----------- ------------ --------- --------- ------------ --------- ----------- ----------- ------------------
  Waveform\   (t)\         (t~r~)\   (B~c~)\   (B~d~)\      (N)\      (F~L~)\     (F~H~)      Pulse Type
  Number      Pulse\       Pulse\    Chirp\    Total\       Number\   Lowest      Highest     
              Width or\    Rise/\    Band\     Frequency\   of\       Channel     Channel     
              Sub-Pulse\   Fall\     width\    Deviation    Chips\    Frequency   Frequency   
              Width\       time\     (MHz)                  Per Pulse (MHz)       (MHz)       
              (u sec)      (u sec)                                                            

  1           0.83         0.02      NA        NA           1         NA          NA          Non-FM pulsed
                                                                                              radars
  ----------- ------------ --------- --------- ------------ --------- ----------- ----------- ------------------

> **Table 2**

Calculated Results

  ----------- ----------- ------------ ------------ ------------- ------------ ---------- -------------- ------------ ------------
  Emission\   (B~s~)      (B~PEP~)\    (B~ref~)\    K\            B(-40)\      (S)\*\     RR Appendix 3\ OOB/\        Spurious\
  Mask\       Frequency   Required\    Reference\   Coefficient   Bandwidth\   Slope\     Spurious\      Spurious\    Domain\
  Number      Hopping     Bandwidth\   Bandwidth\                 (MHz)        (dB/dec)   Attenuation\   Domain\      Correction
              Range (MHz) to Measure\  (MHz)                                              (dB)           Intercept\   (dB)\
                          PEP (MHz)                                                                      Freq (MHz)   Mask /\
                                                                                                                      Data

  1           0           1.205        1.000        7.60          58.987       20.00      -60.00         9111.06\     -58.38\
                                                                                                         9700.94      0.

  2                                                                                                                    
  ----------- ----------- ------------ ------------ ------------- ------------ ---------- -------------- ------------ ------------

![](media/image2.wmf){width="8.552083333333334in"
height="4.989583333333333in"}

[^1]: Procedures for guiding measurement of radar emission spectra for
    determining compliance with ITU-R Radio Regulation Appendix 3 and
    Recommendation ITU-R SM.1541 should be in accordance with
    Recommendation ITU-R m.1177, Techniques for measurement of undesired
    emissions of radar systems.