Instructions for Creating -Spreadsheet for new Modulations -Use of Support Applications
Table of Contents
A
B
C
D
Spreadsheet Organization .................................................................................. 1
ACCPRUtil.exe ................................................................................................. 11
Creating a Data File for ACCPRUtil.exe ........................................................... 11
Sample Copyright Disclaimer............................................................................ 12
Table of Figures
Figure 1, C4FM-ACP ................................................................................................. 1
Figure 2, C4FM-ACCPR-But...................................................................................... 2
Figure 3 C4FM-ACCPR-RRC .................................................................................... 3
Figure 4 C4FM-ACCPR-But-2 ................................................................................... 4
Figure 5 C4FM-25 Small............................................................................................ 5
Figure 6 C4FM-25 Large............................................................................................ 6
Figure 7 C4FM-30 Small............................................................................................ 7
Figure 8 C4FM-30 Large............................................................................................ 8
Figure 9 - Sheet 10, Calculator (C4FM shown).......................................................... 9
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SPD Spreadsheet Instructions
An Excel spreadsheet is provided for each type of modulation referred to in TSB-88B. In addition a template is provided for creating spreadsheets for newly introduced
modulations. See TSB-88-B § 8.8.1.3 SPD Data File Utilization. Lastly, the
application used to create the ACCPR values reported in TSB-88-B, for various
victim receivers IF bandwidths, is described
A Spreadsheet Organization
Each spreadsheet contains 10 sheets. Examples shown are for C4FM.
1. “Modulation”-ACP. This sheet is driven from the Calculator (Sheet 10),
charting the results selected for a “perfect” bandpass filter of bandwidth
ENBW.
C4FM
120 Hz RBW, 31.25 Hz bins, 0.15 dBm Signal Powe
-10
C4FM SPD
ACPR= 71.5 dB
Offset -12.5 kHz
BW 5.5 kHz
-20
-30
Magnitude (dB)
-40
-50
-60
-70
-80
-90
-100
-110
-30
-20
-10
0
Frequency (kHz)
10
Figure 1, C4FM-ACP
1
20
30
2. “Modulation1” ACCPR-But. Driven by the Calculator, charting the
configuration for a Butterworth bandpass filter with 10 poles and 4 cascaded
sections and a bandwidth of ENBW.
C4FM ACCP with 10-4 TIA Butterworth Filter
0
C4FM SPD
But 10-4 Filter
-10
Intercepted Power
ACCP Integration
-20
71.4 dB ACCPR
5.500 kHz ENBW
-30
-12.500 kHz Offset
Magnitude (dB)
-40
-50
-60
-70
-80
-90
-100
-110
-50
-40
-30
-20
-10
0
10
20
30
40
50
Frequency (kHz)
Figure 2, C4FM-ACCPR-But
1
The term “Modulation” is to be filled in by the author. It should describe the type of modulation in
use. E.g. C4FM or some easily recognized descriptor.
2
3. “Modulation” ACCPR-RRC. Driven by the Calculator, charting the
configuration for the Root Raised Cosine bandpass filter with a bandwidth of
ENBW and a roll off factor of alpha (α). Alpha is fixed at 0.2 in all the
spreadsheets.
C4FM with Root Raised Cosine (RRC) TIA Filter
0
C4FM SPD
RRC Filter
-10
Intercepted Power
ACCP Integration
-20
71.3 dB ACCPR
5.500 kHz ENBW
-30
-12.500 kHz Offset
Magnitude (dB)
-40
-50
-60
-70
-80
-90
-100
-110
-50
-40
-30
-20
-10
0
10
20
30
Frequency (kHz)
Figure 3, C4FM-ACCPR-RRC
3
40
50
4. “Modulation” ACCPR-But-2. Driven by the Calculator, charting the
configuration for a Butterworth bandpass filter with 4 poles and 3 cascaded
sections or alternatively by a special case of 5 poles and 4 cascaded sections
as required for the EDACS® modulation for a bandwidth of ENBW.
C4FM ACCP with 4-3 TIA Butterworth Filter
0
C4FM SPD
-10
But 2 Filter
Intercepted Power
-20
ACCP Integration
-30
69.9 dB ACCPR
5.500 kHz ENBW
Magnitude (dB)
-40
-12.500 kHz Offset
-50
-60
-70
-80
-90
-100
-110
-50
-40
-30
-20
-10
0
10
20
30
Frequency (kHz)
Figure 4, C4FM-ACCPR-But-2
4
40
50
5. 25-small. This is a chart of data from sheet 9 (TSB-88-B data). Each chart
contains three of the possible offset frequency values using a 25 kHz
frequency plan with theoretical channel splits. Not all combinations are
assignable, but are provided for completeness. The small offset assignments
are 6.25 kHz, 9.375 kHz and 12.5 kHz. See Annex A, Figure A-1. The legend
reflects the magnitude of ACCPR. This should always be Channel BW, But
10p-4c, RRC and But 4p-3c.
C4FM, 25 kHz Channelization
Offsets 12.5, 9.375 & 6.25 kHz
75
12.5 kHz offset
70
Ch BW
But-10-4
65
RRC
But-4-3
60
9.375 kHz offset
Ch BW
55
But-10-4
50
RRC
But-4-3
ACCPR (dB)
45
6.25 kHz offset
Ch BW
40
But-10-4
35
RRC
But-4-3
30
25
20
15
10
5
0
5
6
7
8
9
10
11
12
13
Victim Receiver ENBW (kHz)
Figure 5, C4FM-25 Small
5
14
15
16
17
18
6. 25-large. This is a chart of data from sheet 9 (TSB-88-B data). Each chart
contains three of the possible offset frequency values using a 25 kHz
frequency plan with theoretical channel splits. The large offset assignments
are 15.625 kHz, 18.75 kHz and 25.0 kHz. See Annex A, Figure A-1.
C4FM, 25 kHz Channelization
Offsets 25.0, 18.75 & 15.625 kHz
90
85
80
75
70
ACCPR (kHz)
25 kHz Offset
Ch BW
65
But-10-4
RRC
60
But-4-3
55
18.75 kHz Offset
Ch BW
50
But-10-4
RRC
45
But-4-3
15.625 kHz Offset
40
Ch BW
But-10-4
35
RRC
But-4-3
30
5
6
7
8
9
10
11
12
13
Victim Receiver ENBW (kHz)
Figure 6, C4FM-25 Large
6
14
15
16
17
18
7. 30-small. This is a chart of data from sheet 9 (TSB-88-B data). Each chart
contains three of the possible offset frequency values using a 30 kHz
frequency plan with theoretical channel splits. The small offset assignments
are 7.5 kHz, 11.25 kHz and 15.0 kHz. See Annex A, Figure A-1.
15.0 kHz Offset
C4FM, 30 kHz Channelization
Offsets 15.0, 11.25 & 7.5 kHz
Ch BW
But-10-4
RRC
But-4-3
80
11.25 kHz Offset
Ch BW
But-10-4
70
RRC
But-4-3
7.5 kHz Offset
Ch BW
60
But-10-4
ACCPR (kHz)
RRC
But-4-3
50
40
30
20
10
0
5
6
7
8
9
10
11
12
13
14
Victim Receiver ENBW (kHz)
Figure 7, C4FM-30 Small
7
15
16
17
18
8. 30-large. This is a chart of data from sheet 9 (TSB-88-B data). Each chart
contains three of the possible offset frequency values using a 30 kHz
frequency plan with theoretical channel splits. The large offset assignments
are 18.75 kHz, 22.5 kHz and 30.0 kHz. Note that the 18.75 kHz offset is also
possible in a 25 kHz plan. See Annex A, Figure A-1.
C4FM, 30 kHz Channelization
Offsets 30.0, 22.5 & 18.75 kHz
90
85
30 kHz Offset
80
Ch BW
ACCPR (kHz)
But-10-4
75
RRC
But-4-3
70
22.5 kHz Offset
Ch BW
But-10-4
65
RRC
But-4-3
60
18.75 kHz Offset
Ch BW
But-10-4
55
RRC
But-4-3
50
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Victim Receiver ENBW (kHz)
Figure 8, C4FM-30 Large
9. TSB88B Data. This sheet contains the data from ACCPRUtil.exe (see §B for
information on the application) and is the source data for the charts on sheets
5 through 8. The data from ACCPRUtil.exe can be pasted into the
appropriate tables on the left hand side. The left hand side tables drive the
tables further to the right creating the figures that are presented in Annex A
for the modulation being evaluated.
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10. Calculator. This sheet provides complete flexibility to calculate any offset
value for any ENBW bandpass value for the four filters.
Carrier Frequency
Bin Size
RBW
Butterworth Filter #1
F +/-3dB
3.007 kHz
# of Poles
10
# of Cascades
4
IF fc Offset -12.500 kHz
150.000 MHz
31.25 Hz
119 Hz
Signal Power
1.03 mW
0.147 dBm
Equivalent Noise BW
ACCPR
Adjacent Channel Power
Offset
BW
-12.5 kHz
5.5 kHz
Start
Stop
Butterworth Filter #2
F +/-3dB
3.267 kHz
# of Poles
4
# of Cascades
3
IF fc Offset -12.500 kHz
-15.25 kHz
-9.75 kHz
ACPR
71.45 dB
Equivalent Noise BW
ACCPR
Enter frequency offset (kHz) & select side
Offset Frequency
12.500 kHz
High Side
1
5.500 kHz
69.9 dB
RRC Filter
Fsymbol=
5.5 ksps
alpha=
0.2
Maximum
-120
IF fc Offset -12.500 kHz
Red = Entered values
Blue = Calculated values
Low Side
5.500 kHz
71.4 dB
Equivalent Noise BW
ACCPR
5.500 kHz
71.3 dB
Offse
ENBW
ACCP
Offse
ENBW
ACCP
Offse
ENBW
ACCP
5.500 kHz
Rcvr ENBW
Enter Victim's ENBW (kHz), select alternate BF2 if applicable
BF2 4P3C (Normal)
BF2 5P-4C
3
Butterworth Calculator
BF1 10p-4c
3.006905518
BF2 4p-3c
3.266999922
BF2 5p-4c
3.272830330
Figure 9, Sheet 10, Calculator (C4FM shown)
Numerical values in red are entered values. Numerical values in blue are calculated
values based on the red values. In the calculator sheet the only inputs are Rcvr
ENBW (kHz), 5.5 kHz and the Offset Frequency (kHz) 12.5 kHz. There are two
interlocked buttons to select whether the calculation is based on a victim receiver
being below (low side) or above (high side) of the interfering carrier. The
Supplementary Application ACCPRUtil.exe performs both calculations and reports
the lowest ACCPR value.
9
Each filter type has its own calculator. The Adjacent Channel Power calculator is for
a perfect bandpass filter of ENBW kHz. It is labeled as ACPR to reflect its FCC
utilization for proscribed bandwidths.
There are two Butterworth filters. Butterworth #1 is fixed for 10 poles, 4 cascaded
sections. In the example it reports an ACCPR of 71.4 dB, very close to the perfect
filter reporting 71.5 dB. The difference between values varies with the offset
frequency value and the modulation being evaluated.
The second Butterworth filter can have two different configurations. The normal or
default is for 4 poles, 3 cascaded sections, representing a typical older analog radio
implementation. Alternatively it can be set for a 5 pole, 4 cascaded sections
representing the EDACS® implementation. This selection is made by the interlocked
buttons below the ENBW input field. The purpose of this selection is to reduce the
number of filter combinations. For the EDACS® radios, the 5p-4c represents the
actual filter implementation, but the more commonly used 4p-3c configuration with a
lower ENBW is used to calculate the ACCPR. The different values are reported in
TSB 88-B Table 2 - IF Specifications for Simulating Receivers.
The Butterworth filter calculator requires that the individual cascaded sections have
a wider bandwidth than the final ENBW. A formula to calculate this process is
included in the calculator. Therefore only the three predefined Butterworth
configurations are valid in this calculator. If any other configuration is used, the
correct conversion needs to be developed. The Excel tool “Goal Seek” is
recommended. Use it to develop the correct values for the lowest and highest
ENBW values. From those values the conversion can be developed.
The Root Raised Cosine filter is the lower right one. It reports an ACCPR of 71.3
dB.
Each spreadsheet is “protected” but without a password so changes are possible but
unsupported. Caution is advised in changing any of the blue numerical values as
this can change the charts in Sheets 1-4 without properly updating the legend and
other descriptions on the charts.
The charted values, Sheets 5-8, should always have the best ACCPR (ACPR) in the
following order:
ƒ
ƒ
ƒ
ƒ
Channel Bandwidth
Butterworth 10p-4c
RRC
Butterworth 4p-3c
Note that on Sheet 9 the tables are organized from left to right:
ƒ
Channel Bandwidth
10
ƒ
ƒ
ƒ
RRC
Butterworth 10p-4c
Butterworth 4p-3c
Be careful to paste directly from the ACCPRUtil.exe outputs as they are arranged to
be compatible with Sheet 9 requirements.
The greatest filter differences occur in the medium offset values. Sheets 5 - 8
demonstrate this. For very small offsets, there is little difference as with large
offsets.
B ACCPRUtil.exe
This utility is used to calculate the worst case2 (lowest) ACCPR for the template. It
is provided on the companion CD to TSB-88-B.
1. Select the TX Spectral Power Density. Select the file with the modulation
to be evaluated.
2. Select the RX IF Filter. The utility offers three choices.
a. The single offset has different filter configurations to select in a pull
down menu. For each filter selection the input variables are
presented as well as the offset frequency.
b. The range has the same filter pull down menu and offers a “Pseudoswept” output between two offsets with a fixed step value.
c. The TIA method creates the file appropriate for insertion on Sheet 9
to drive the results charts on Sheets 5 through 8. There are three
choices, Low Side, High Side or Worst Case. To follow TIA
methodology, the Worst Case should be selected.
3. Output Selection. The Excel spreadsheet is the preferred output. This file
will also include Curve fit values which are no longer applicable. Please
disregard.
C Creating a Data File for ACCPRUtil.exe
The application requires a data file with the suffix.spd. A “Template.spd” file is
provided as a template for creating a utility spd file for the application. It is already
populated with C4FM data. The data from the test equipment should be pasted in
the cells below the ## symbol, cells 9 and higher. Failure to observe the proper cell
numbers may make the application reject the file. The values should be in dBm.
The template is based on the spacing of 31.25 Hz/bin. Save this file as
“Modulation.spd”; save as text (delimited). Excel will caution but proceed. The
application must see the file name extension spd and be a text file.
2
Other cases can be calculated. Only the worst case is used in TSB-88-B. The difference between
high side and low side calculated values will normally be minimal unless the modulating signal is
asymmetrical.
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Place the newly created spd file in the same directory as the application. The
application can now execute this file when selected.
Place the various data files produced by the application into Sheet 9 to create a
complete Spreadsheet. Be sure to re-label the sheet names on Sheets 1-4 and the
titles of Sheets 1-8. This text is indicated as XXX for easy identification. The Y axis
may need rescaling.
Forward the completed spreadsheet to the Chair of TIA Engineering Subcommittee
TR8.18 for review and further distribution and possible inclusion into future updates
of TSB 88. To determine the Chair browse:
http://www.tiaonline.org/about/staff.cfm#Standards and Technology, and find the
Manager, Standards Secretariat Services and request the address of the current
Chair person. Submittals should include the TIA standard copyright disclaimer.
D Sample Copyright Disclaimer
[Contributor Company3] grants an irrevocable royalty-free and
compensation-free license to the Telecommunications Industry
Association to use any or all material contained in the contribution in
any TIA publication.
3
Insert the name of the contributing company between the square brackets and eliminate the square
brackets.
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