SX1272/3
ETSI Compliance
Application Note
WIRELESS & SENSING
ETSI Compliance of the SX1272/3 LoRa Modem
AN1200.10
TCo
Revision 1 July 2013 © 2013 Semtech Corp.
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SX1272/3
ETSI Compliance
Application Note
WIRELESS & SENSING
Table of Contents
1.
2.
3
3.1
3.2
3.3
3.4
3.5
4
4.1
4.2
4.3
4.4
5
6
7
8
9
Introduction ................................................................................................................................................... 3
Applicable Bands: Overview ........................................................................................................................ 3
Band Edge Limit Testing .............................................................................................................................. 4
Sub-Band G (Note 7) ...................................................................................................................................... 4
Sub-Band G1................................................................................................................................................... 7
Sub-Band G2................................................................................................................................................. 10
Sub-Band G3................................................................................................................................................. 12
Sub-Band G4................................................................................................................................................. 13
Transient Power Tests ................................................................................................................................ 15
Modulation Bandwidth ................................................................................................................................... 15
125 kHz Transient Power .............................................................................................................................. 17
250 kHz Transient Power .............................................................................................................................. 19
500 kHz Transient Power .............................................................................................................................. 20
Peak RF Output Power Measurement ....................................................................................................... 21
Spurious emissions .................................................................................................................................... 23
Conclusion ................................................................................................................................................... 24
References ................................................................................................................................................... 24
Appendix 1: Centre Frequencies ............................................................................................................... 24
Table of Figures
Figure 1. Band G (Note 7) 6 dBm RF Output Power 500 kHz Bandwidth .................................................................... 4
Figure 2. Band G (Note 7) 6 dBm RF Output Power 250 kHz Bandwidth ..................................................................... 5
Figure 3. Band G (Note 7) 6 dBm RF Output Power 125 kHz Bandwidth ..................................................................... 6
Figure 4. Sub-Band G1 13 dBm RF Output Power 125 kHz Bandwidth ........................................................................ 7
Figure 5. Sub-Band G1 13 dBm RF Output Power 250 kHz Bandwidth ........................................................................ 8
Figure 6. Sub-Band G1 14 dBm RF Output Power 500 kHz Bandwidth ........................................................................ 9
Figure 7. Sub-Band G2 13 dBm RF Output Power 250 kHz Bandwidth ......................................................................10
Figure 8. Sub-Band G2 13 dBm RF Output Power 125 kHz Bandwidth ......................................................................11
Figure 9. Sub-Band G3 20 dBm RF Output Power 125 kHz Bandwidth ......................................................................12
Figure 10. Sub-Band G4 13 dBm RF Output Power 125 kHz Bandwidth ....................................................................13
Figure 11. Sub-Band G4 6 dBm RF Output Power 125 kHz Bandwidth ......................................................................14
Figure 12. 125 kHz Modulation Bandwidth ..................................................................................................................15
Figure 13. 250 kHz Modulation Bandwidth ..................................................................................................................16
Figure 14. 500 kHz Modulation Bandwidth ..................................................................................................................16
Figure 15. 125 kHz BW, Step 1 Measurement ...........................................................................................................17
Figure 16. 125 kHz BW, Step 1 Reference Power Measurement ..............................................................................18
Figure 17. 125 kHz BW, Step 2 Measurement at +120 kHz ........................................................................................18
Figure 18. 250 kHz BW, Step 1 non-compliance and reference power measurement. ...............................................19
Figure 19. 250 kHz BW, step 2 compliance. ................................................................................................................19
Figure 20. 500 kHz Step 1 compliant transient power measurement. .........................................................................20
Figure 21. Programmed RF Output Power = 6 dBm. Yields a BW invariant +6.2 dBm /100 kHz PSD measurement.
..............................................................................................................................................................................21
Figure 22. Programmed RF Output Power = 13 dBm. Yields a 13.9 dBm compliant output. ......................................22
Figure 23. Programmed RF Output Power = 7 dBm. Yields a 7 dBm compliant RF output power. ............................22
Figure 24. Sub-1 GHz compliant spurious and harmonic emissions. ..........................................................................23
Figure 25. 1 GHz to 6 GHz compliant spurious and harmonic emissions. ..................................................................23
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SX1272/3
ETSI Compliance
Application Note
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1. Introduction
The SX1272/3 is equipped with both conventional FSK and spread spectrum LoRa modems. This guide illustrates
the regulatory tests required by the ETSI Standard EN 300 220 V2.4.1 (2012-05) [1] in the bands and sub bands
th
specified in the ERC Recommendation 70-03 (9 October 2012) [2].
The guide is limited to transmitter testing only as the most stringent requirement to be passed by the radio. The
SX1272/3 is typically compliant with all wideband receiver tests. For full details of the LoRa modem and its operation
please see the SX1272/3 datasheet [3] and design guide [4].
2. Applicable Bands: Overview
The ERC REC 70-03 defines the bands in which license free ISM band short range devices are permitted to
operate. LoRa is a wideband spread spectrum modulation technique hence the regulatory bands which support
wideband modulation schemes, and so apply to LoRa modulation, are summarized along with the applicable
regulatory limitations in the table below.
Table 1. Bands and sub-bands for 868 MHz band operation that support wideband modulation
Band
Edge Frequencies
Fe865 MHz
865 MHz
868 MHz
868.7 MHz
869.4 MHz
869.7 MHz
869.7 MHz
g(Note 7)
g(Note 7)
g1
g2
g3
g4
g4
Fe+
868 MHz
870 MHz
868.6
869.2 MHz
869.65 MHz
870 MHz
870 MHz
Field / Power
+6.2 dBm /100 kHz
-0.8 dBm / 100 kHz
14 dBm
14 dBm
27 dBm
7 dBm
14 dBm
Spectrum Access
1 % or LBT AFA
0.1% or LBT AFA
1 % or LBT AFA
0.1% or LBT AFA
10 % or LBT AFA
No requirement
1 % or LBT AFA
Band Width
3 MHz
5 MHz
600 kHz
500 kHz
250 kHz
300 kHz
300 kHz
The transmitter performance in all of the sub-bands listed above was tested with the following caveats and
exceptions:


Note 4 audio and video applications from 863 to 865 MHz not tested.
-0.8 dBm / inaccessible with the SX1272EVK, so the 865 to 870 MHz (Note 7) band was not tested.
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3 Band Edge Limit Testing
With the radio programmed to the relevant output power limit as specified in Table 1 the compliance with each of the
band edges and the number of channels possible within each sub band is shown in the following sequence of
graphs. Note that the band edges were measured in accordance with the spectral band edge masks of Section 7.7
of the EN 300 220 [1]. For convenience the resulting time on air permissible is also tabulated in each case.
3.1 Sub-Band G (Note 7)
Figure 1. Band G (Note 7) 6 dBm RF Output Power 500 kHz Bandwidth
Time On Air
Duty cycle
36 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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Figure 2. Band G (Note 7) 6 dBm RF Output Power 250 kHz Bandwidth
Time On Air
Duty cycle
36 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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Figure 3. Band G (Note 7) 6 dBm RF Output Power 125 kHz Bandwidth
Time On Air
Duty cycle
36 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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3.2 Sub-Band G1
Figure 4. Sub-Band G1 13 dBm RF Output Power 125 kHz Bandwidth
Time On Air
Duty cycle
36 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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Figure 5. Sub-Band G1 13 dBm RF Output Power 250 kHz Bandwidth
Time On Air
Duty cycle
36 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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Some applications may find it useful to avail of a full 500 kHz bandwidth signal in the G1 band. To this end the
limiting first band edge was tested. The resulting plot is shown below. To minimise the transmitter spectrum we use
additional narrower transmit spectral filtering. Here we see that the Tx output power possible is approximately
14 dBm, dependent upon the stability of the transmitter reference oscillator.
To activate the transmitter filter for application in this band, register 0x3D must be written with the contents 0xE1.
Figure 6. Sub-Band G1 14 dBm RF Output Power 500 kHz Bandwidth
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3.3 Sub-Band G2
Figure 7. Sub-Band G2 13 dBm RF Output Power 250 kHz Bandwidth
Time On Air
Duty cycle
3.6 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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Figure 8. Sub-Band G2 13 dBm RF Output Power 125 kHz Bandwidth
Time On Air
Duty cycle
3.6 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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3.4 Sub-Band G3
Figure 9. Sub-Band G3 20 dBm RF Output Power 125 kHz Bandwidth
Time On Air
Duty cycle
360 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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3.5 Sub-Band G4
Figure 10. Sub-Band G4 13 dBm RF Output Power 125 kHz Bandwidth
Time On Air
Duty cycle
36 secs / hr
LBT + AFA
100 secs / hr / 200 kHz
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Figure 11. Sub-Band G4 6 dBm RF Output Power 125 kHz Bandwidth
No Timing Restriction
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4 Transient Power Tests
4.1 Modulation Bandwidth
Prior to measurement of the transient power performance of the radio it is necessary to determine the modulation
bandwidth. The following three plots show the measured modulation bandwidth in the three LoRa bandwidth
settings.
Figure 12. 125 kHz Modulation Bandwidth
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Figure 13. 250 kHz Modulation Bandwidth
Figure 14. 500 kHz Modulation Bandwidth
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4.2 125 kHz Transient Power
With the measurement bandwidth determined the 100 kHz offset transient power analysis can be performed. Here
only the upper side power was measured. Due to the 120 kHz RBW stipulated in the measurement, the transient
power fails the -36 dBm ‘step 1 limit’, meaning that step 2 must be performed.
Figure 15. 125 kHz BW, Step 1 Measurement
Two ensuing measurements are made: The first is the reference power measurement, again performed at the same
100 kHz offset as the first measurement. All following measurements at 120 kHz intervals must be lower that this
level out to 2 MHz offset or until the -36 dBm limit is reached. The final measurement in the sequence shows that at
the first 120 kHz offset the power level is below the regulatory limit. No further testing was hence required.
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Figure 16. 125 kHz BW, Step 1 Reference Power Measurement
Figure 17. 125 kHz BW, Step 2 Measurement at +120 kHz
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4.3 250 kHz Transient Power
An identical process and pattern of compliance was followed at 250 kHz, the first 120 kHz offset channel of step 2
yielding compliance.
Figure 18. 250 kHz BW, Step 1 non-compliance and reference power measurement.
Figure 19. 250 kHz BW, step 2 compliance.
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4.4 500 kHz Transient Power
At the 500 kHz BW setting only a single measurement was required. At the 100 kHz offset from the band edge the
transient power spectrum was compliant in step 1 of the measurement process.
Figure 20. 500 kHz Step 1 compliant transient power measurement.
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5
Peak RF Output Power Measurement
The peak RF output power was measured at the settings required by the ERC-REC 70-03.
Figure 21. Programmed RF Output Power = 6 dBm. Yields a BW invariant +6.2 dBm /100 kHz PSD
measurement.
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Figure 22. Programmed RF Output Power = 13 dBm. Yields a 13.9 dBm compliant output.
Figure 23. Programmed RF Output Power = 7 dBm. Yields a 7 dBm compliant RF output power.
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6 Spurious emissions
Figure 24. Sub-1 GHz compliant spurious and harmonic emissions.
Figure 25. 1 GHz to 6 GHz compliant spurious and harmonic emissions.
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7 Conclusion
ETSI compliance of the LoRa modem transmitter has been shown in all tests required for wideband modulation
formats. The compliant conditions are detailed for all European sub bands are summarized in the table below.
Band
g(Note 7)
g1
g2
g3
g4
g4
Edge Frequencies
Fe865 MHz
868 MHz
868.7 MHz
869.4 MHz
869.7 MHz
869.7 MHz
Field / Power
Fe+
868 MHz
868.6
869.2 MHz
869.65 MHz
870 MHz
870 MHz
+6.2 dBm /100 kHz
14 dBm
14 dBm
20 dBm
7 dBm
14 dBm
Number of Channels
125 kHz
15
3
2
1
1
1
250 kHz
10
1
1
-
500 kHz
4
*
-
* Up to 14 dBm output power possible with modified Tx filter settings.
8 References
[1]
ETSI EN 300 220-1, V2.4.1 “Electromagnetic compatibility and Radio spectrum Matters (ERM)
Short Range Devices (SRD) Radio equipment to be used in the 25 MHz to 1 000 MHz frequency range with
power levels ranging up to 500 mW” Part 1: Technical characteristics and test methods. May 2012.
[2]
REC Recommendation 70-03 Editon of October 2012 “Relating to the use of Short Range Devices (SRD)"
Tromsø 1997, CEPT ECC (Subsequent amendments 9 October 2012).
[3]
Semtech Corp SX1272/3 Datasheet, TCo April 2013.
[4]
Semtech Corp Application Note No. “SX1272/3 LoRa: Optimising the LoRa Modem Configuration”, TCo April
2013.
9 Appendix 1: Centre Frequencies
The list of centre frequencies used in each sub-band test are given in the table below.
Band
g(Note 7)
g1
g2
g3
g4
g4
Centre Frequencies
Channel 1 [MHz] + Channel Spacing [MHz]
125 kHz
250 kHz
500 kHz
865.10 + 0.2
865.20 + 0.3
865.60 + 0.6
868.50 + 0.8
868.30
868.30
868.85 + 0.2
868.95
869.525
869.85
869.85
-
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