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9 GHz Maritime Radar Characteristics

By Jeff Graham,2014-05-07 20:33
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9 GHz Maritime Radar Characteristics

     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

    1 Measured emission spectrum data may be imported into the program. 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

     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.

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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) based on the measured data. If you select the Frequency Hopping O

    Mode, the Lowest Channel Frequency (F) and Highest Channel Frequency (F) windows LH

    will display the selected F and F frequencies based on the measured data. In cases where LH

    there are multiple operating (fundamental) frequencies, or the radar is a frequency hopping

    radar, the program may not select the appropriate Operating Frequency (F), or in the case O

    of frequency hopping radar the Lowest Channel Frequency (F) and Highest Channel L

    Frequency (F) for plotting the ITU-R emission mask. If the appropriate F, F , or F HOLH

    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

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    ) to 0 dB. Verify that the FO O

    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 in Row 6, should be midway between F and F. OLH

     normalize the power level at the fundamental frequency (F

    G. If desired, the frequency scale of the measured data can be normalized to Zero MHz/GHz at

    the radar Fundamental Frequency (F). Verify that the value to normalize the measured data O

    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

    ) in Row 9 of the spreadsheet. The measurement m

    bandwidth (B) should be in the units of MHz. m

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

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     -40

    dB bandwidth (see Recommendation ITU-R SM.1541, Section 3.1).

mask limits are determined from the pulse type (waveform) which results in the maximum B 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

    ) must have data entered into it for the rise time r

    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) must have c

    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) must have data entered d

    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 and F) must have data entered into it for the lowest and highest channel LH

    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.

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    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 dB bandwidth can be offset -40 Recommendation ITU-R SM.1541, Section 4, states that Bfrom 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.

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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.

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    SAMPLE DATA 1

    Aeronautical Radionavigation Radar F 2844.4 MHz 0 PEP 1.300 Megawatts

    B 1 MHz m

     Table 1

     Pulse/Sub-pulse Characteristics

    ) (B) (B) (N) (F) (F) (t) (trcdLH

    Pulse Chirp Total Number Lowest Highest Pulse

    Rise/ Band Frequency of Channel Channel Width or Waveform Fall width Deviation Chips Frequency Frequency Pulse Type Sub-Number time (MHz) Per (MHz) (MHz) Pulse

    (u sec) Pulse Width

    (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

    ) (B) (B) K B(-40) (S)* RR OOB/ Spurious (BsPEPref

    Frequency Required Reference Coefficient Bandwidth Slope Appendix 3 Spurious Domain

    Hopping Bandwidth Bandwidth (MHz) (dB/dec) Spurious Domain Correction Emmision

    Range to (MHz) Attenuation Intercept (dB) Mask

    (MHz) Measure (dB) Freq Mask / Number

    PEP (MHz) Data

    (MHz)

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

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

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     Aeronautical Radionavigation Radar

    20

    0

    -20

    Data-40M1: 20 dB/dec

    -60M2: 40 dB/dec

    -80

    -100

    -120

    255026502750285029503050315032503350Received Power Normalized to Maximum (dB)

    Frequency, MHz

    Mask 1: , t=0.6, tr=0.05, Bc=NA, Bc=NA, N=1, FL=NA, FH=NA, Bs=0, B(-40)=35.796, S=40., X(dB)=-60.Mask 2: , t=0.6, tr=0.05, Bc=NA, Bc=NA, N=1, FL=NA, FH=NA, Bs=0, B(-40)=35.796, S=40., X(dB)=-60.

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    SAMPLE DATA 2

     Maritime Radionavigation Radar

     F 9406 MHz 0

    PEP 12.000 Kilowatts

    B 1 MHz m

    Table 1

     Pulse/Sub-pulse Characteristics

    ) (B) (B) (N) (F) (F) (t) (trcdLH

    Pulse Chirp Total Number Lowest Highest Pulse

    Rise/ Band Frequency of Channel Channel Width or Waveform Fall width Deviation Chips Frequency Frequency Pulse Type Sub-Number time (MHz) Per (MHz) (MHz) Pulse

    (u sec) Pulse Width

    (u sec)

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

    Table 2

     Calculated Results

    ) (B) (B) K B(-40) (S)* RR OOB/ Spurious (BsPEPrefFrequency Required Reference Coefficient Bandwidth Slope Appendix 3 Spurious Domain

    Hopping Bandwidth Bandwidth (MHz) (dB/dec) Spurious Domain Correction Emission

    Range to (MHz) Attenuation Intercept (dB) Mask

    (MHz) Measure (dB) Freq Mask / Number

    PEP (MHz) Data

    (MHz)

    9111.06 -58.38 1 0 1.205 1.000 7.60 58.987 20.00 -60.00 9700.94 0. 2

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    Maritime Radionavigation Radar - Long Pulse

    20

    0

    -20

    Data-40

    M1: 20 dB/dec-60

    -80

    -100

    -120

    730078008300880093009800103001080011300Received Power Normalized to Maximum (dB)

    Frequency, MHz

    Mask 1: , t=0.83, tr=0.02, Bc=NA, Bc=NA, N=1, FL=NA, FH=NA, Bs=0, B(-40)=58.987, S=20., X(dB)=-60.

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