AN4148 Application note Using the SPIRIT1 transceiver under ARIB STD-T93 in the 315 MHz band By Placido De Vita Introduction The SPIRIT1 is a very low power RF transceiver, intended for RF wireless applications in the sub-1 GHz band. It is designed to operate both in the license-free ISM and SRD frequency bands at 169, 315, 433, 868, 915 and 920 MHz. The ARIB (Japanese association of radio industries and businesses) was established in response to several trends such as the growing internationalization of telecommunications, the convergence of telecommunications and broadcasting, and the need for promotion of radio related industries. The scope of the ARIB organization is to define the basic technical requirements for standard specifications of radio equipment. This application note outlines the expected performance when using the SPIRIT1 under ARIB STD-T93 [2] in the 315 MHz band. For details on the regulatory limits in the 315 MHz frequency band, please refer to the ARIB STD-T93 regulations [2]. These can be downloaded from www.arib.or.jp/english/index.html August 2012 Doc ID 023517 Rev 1 1/13 www.st.com Contents AN4148 Contents 1 An overview of ARIB STD-T93 regulation . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 Transmitter parameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.1 4 Permissible values for spurious emission intensity . . . . . . . . . . . . . . . . . . 8 Receiver parameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4.1 Conducted spurious component at receiver . . . . . . . . . . . . . . . . . . . . . . . 10 5 Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2/13 Doc ID 023517 Rev 1 AN4148 1 An overview of ARIB STD-T93 regulation An overview of ARIB STD-T93 regulation The ARIB STD-T93 standard provides for telemetry radio equipment designed to automatically indicate and/or record the results obtained by measuring instruments located remotely; telecontrol radio equipment for transmission of signals to activate, change or deactivate the functions of devices located remotely by means of radio waves; data transmission radio equipment intended for the transmission of information to be processed primarily by machines, or of previously processed information that uses the frequency of 315 MHz. Expected application is air pressure monitoring equipment for tire and keyless entry systems for automotive. Audio and sound data is eliminated from this regulation. The operating frequency band is defined as above 312 MHz to below 315.25 MHz. The antenna power for frequencies above 312 MHz and below 315.25 MHz must be below 25 µW (- 16 dBm) EIRP (equivalent isotropically radiated power). Also, antenna power (EIRP) shall be below 205 uW (- 6.9 dBm) when the center of the frequency band added deviation of frequency to occupied frequency band is between 312 MHz and 315.05 MHz. There are no specific requirements for the modulation method, modulation rate, frequency deviation, coding type, and adjacent channel leakage power. The permissible value for an occupied bandwidth (the bandwidth such that the mean power radiated below its lower frequency limit and above its upper frequency limit are each equal to 0.5% of the total mean power radiated by a given emission) shall be 1 MHz. “Spurious emission” refers to the emission on a frequency or frequencies which are outside the permitted bandwidth and the level of which may be reduced without affecting the corresponding transmission of information, including a high harmonic emission, a low harmonic emission, a parasitic emission and an intermodulation product, but excluding an out-of-band emission. “Out-of-band emission” refers to the emission which results from the modulation process on a frequency or frequencies outside the permitted bandwidth. “Unwanted emission” refers to the emission consisting of the spurious emission and the outof-band emission. “Permissible value of the unwanted emission intensity” refers to the permissible value defined according to the mean power of unwanted emissions of each modulated frequency supplied to the feeder. Permissible value of the unwanted emission intensity is shown in Table 1. For the receiver part, a conducted spurious component is defined. Permissible value of the receiver conducting spurious components is defined in Table 2. Doc ID 023517 Rev 1 3/13 An overview of ARIB STD-T93 regulation Table 1. value of the permissible value of the unwanted emission intensity Frequency band [GHz] Maximum permissible value of the unwanted emission intensity Reference bandwidth [nW] e.i.r.p. [dBm] e.i.r.p. Below 1 250 - 36 100 kHz Above 1 1000 - 30 1 MHz Table 2. value of the conducted spurious component at receiver Frequency band [GHz] 4/13 AN4148 Maximum permissible value of the unwanted emission intensity Reference bandwidth [nW] EIRP [dBm] EIRP Below 1 4 -54 100 kHz Above 1 4 -54 1 MHz Doc ID 023517 Rev 1 AN4148 2 Application circuit Application circuit Figure 1 shows an image of the SPIRIT1 application board. The application is made up of 2 boards: a daughterboard and a motherboard. The daughterboard contains the SPIRIT1 with the circuits necessary for it to work. For correctly functionality, the daughterboard must be plugged into the motherboard (see Figure 2) by two header 5x2 connectors (J6 and J7). The motherboard is provided with an STM32L152VBT6 microcontroller to correctly program the transceiver. The microcontroller is programmed with firmware developed for the SPIRIT1 application. A graphical user interface (GUI) is developed to correctly program the SPIRIT1. The daughterboard is provided with a 52 MHz XTAL to provide the correct oscillator to the SPIRIT1. The SPIRIT1 has an internal SMPS that drastically reduces power consumption, making it the best-in-class for application on this bandwidth. The SMPS is fed from the battery (1.8 V to 3.6 V) and provides the device with a programmable voltage (1.4 V typical). An SMA connector is present to connect the board to an antenna or to instrumentation to verify the correct functionality and verify the ETSI standard request. A few of passive devices (inductors and capacitors) are used for matching/filtering in the power amplifier (PA) and balun network for the receiver. To reduce application costs, the SPIRIT1 is designed to work without an external antenna switch. The daughterboard is designed to show the SPIRIT1 functionality in this condition. Clearly, an application with antenna switch can be realized, but this is not described in this document. Figure 1. SPIRIT1 application daughterboard AM13146v1 Doc ID 023517 Rev 1 5/13 Application circuit Figure 2. AN4148 SPIRIT1 application daughterboard plugged into the motherboard AM13147v1 6/13 Doc ID 023517 Rev 1 3V3 10 8 6 4 2 9 7 5 3 1 10 8 6 4 2 9 7 5 3 1 Doc ID 023517 Rev 1 R_0R0_0402 B2=433MHz 6 R8 XOUT B3=868MHz B3=915MHz B3=920MHz R_0R0_0402 R11 R_0R0_0402 R10 R_0R0_0402 R9 8 R_0R0_0402 GPIO_1 7 B1=315MHz XIN R7 GPIO_2 9 Mount resistor relative to used band C_12P_0402_C0G_J_50 RXP B0=169MHz VBAT2 11 12 13 14 15 C_TBD_0402_C0G C19 L7 L_10U_0805 C_10P_0402_C0G_J_50 C10 REXT TX SMPS2 21 R_0R0_0402 GPIO_3 10 C9 RXN XTAL SDn SMPS1 GND NX3225GA-xxMHz (XTAL) Y1 VREG SPIRIT1_2 4 SCLK 5 CSn VBAT1 R6 SDO SDI SCLK CSn 20 3 SDI 19 J7 HEADER 5X2 C21 C_100p_0402_C0G C_100n_0402_X7R C0 17 2 SDO 18 1 GPIO_0 U1 C_330p_0402_C0G C22 SDn C20 C_1U_0603_X7R_K_6V3 16 GPIO0 GPIO3 GPIO2 GPIO1 SPIRIT_DUMMY1 VCC_RF L8 C4 C1 L_TBD_0402 L2 C_TBD_0402_C0G L_TBD_0402 L4 C_TBD_0402_C0G C5 C_TBD_0402_C0G C_TBD_0402_C0G C8 C13 C_TBD_0402_X7R C_TBD_0402_C0G C_TBD_0402_C0G C2 C3 C_TBD_0402_C0G L3 L_TBD_0402 C_TBD_0402_C0G C7 C_TBD_0402_C0G L_TBD_0402 L_TBD_0402 L6 C6 L5 C_TBD_0402_C0G C15 L1 C14 C12 C_100n_0402_X7R L_TBD_0402 L9 C11 C_1U_0603_X7R_K_6V3 R13 R_TBD_0402 R12 R_TBD_0402 L0 L_TBD_0402_50M L_TBD_0402 L_TBD_0402 DUMMY3 3V3 J1 RF_IN/OUT Figure 3. DUMMY3 J6 HEADER 5X2 SPIRIT_DUMMY2 AN4148 Application circuit Daughterboard schematic AM13166v1 7/13 Transmitter parameter 3 AN4148 Transmitter parameter All of the measurements reported here are measured using the following parameters: Tc = 25 ° C, Vdd = 3.0 V, f = 313.5 MHz (middle frequency of the useful bandwidth), unless otherwise specified. The maximum output power of the SPIRIT1 in this band is 10 dBm, so all the measurements are performed at the levels required by the standard, that is - 16 dBm. The permissible value for an occupied bandwidth defined in the standard is 1 MHz. The occupied bandwidth from the SPIRIT1 when the maximum permitted data rate and deviation are used is lower than 1 MHz, so no measurements are performed to verify this parameter. There are no specific requirements in the standard about setting of detector or video bandwidth (VBW) of the spectrum analyzer used for the measurement. The detector will be set to peak, the video bandwidth will be set equal to the resolution bandwidth, and the display will be set to peak hold. 3.1 Permissible values for spurious emission intensity “Spurious emission” refers to the emission on a frequency or frequencies which are outside the permitted bandwidth and the level of which may be reduced without affecting the corresponding transmission of information, including a high harmonic emission, a low harmonic emission, a parasitic emission and an intermodulation product, but excluding an out-of-band emission. “Out-of-band emission” refers to the emission which results from the modulation process on a frequency or frequencies outside the permitted bandwidth. “Unwanted emission” refers to the emission consisting of the spurious emissions and the out-of-band emissions. “Permissible value of the unwanted emission intensity” refers to the permissible value defined according to the mean power of unwanted emissions of each modulated frequency supplied to the feeder. Permissible values of the unwanted emission intensity are shown in Table 1. The measurements performed are printed in Figure 4 and 5. From these images it is possible to see that all of the requirements are met. 8/13 Doc ID 023517 Rev 1 AN4148 Transmitter parameter Figure 4. TX spurious emission below 1 GHz 0 Output power ARIB mask -10 Output power [dBm] -20 -30 -40 -50 -60 -70 0.0E+00 1.0E+08 2.0E+08 3.0E+08 4.0E+08 5.0E+08 6.0E+08 7.0E+08 8.0E+08 9.0E+08 1.0E+09 Frequency [Hz] AM13276v1 TX spurious emission above 1 GHz 0 Output power ARIB mask -10 -20 Output power [dBm] Figure 5. -30 -40 -50 -60 -70 1.0E+09 1.5E+09 2.0E+09 2.5E+09 3.0E+09 3.5E+09 4.0E+09 4.5E+09 5.0E+09 Frequency [Hz] AM13277v1 Doc ID 023517 Rev 1 9/13 Receiver parameter 4 AN4148 Receiver parameter ARIB compliance in ARIB STD-T93 [2] in the 312 to 315.25 MHz band only pertains to emissions and harmonics. There are no receiver sensitivity, selectivity or blocking measurements to comply with ARIB STD-T93 standard [2]. 4.1 Conducted spurious component at receiver Spurious radiation from the receiver are components at any frequency, radiated by the equipment. The spurious emission strength at the antenna input must be less than the values in Table 2. The measurement results are shown in Figure 6 and 7. All standard requirements are met from the SPIRIT1 in receiver mode. Figure 6. TX spurious emission below 1 GHz -40 Output power ARIB mask -45 Output power [dBm] -50 -55 -60 -65 -70 0.0E+00 1.0E+08 2.0E+08 3.0E+08 4.0E+08 5.0E+08 6.0E+08 7.0E+08 8.0E+08 9.0E+08 1.0E+09 Frequency [Hz] Figure 7. AM13278v1 TX spurious emission above 1 GHz -40 Output power ARIB mask -45 Output power [dBm] -50 -55 -60 -65 -70 1.0E+09 1.5E+09 2.0E+09 2.5E+09 3.0E+09 3.5E+09 Frequency [Hz] 10/13 Doc ID 023517 Rev 1 4.0E+09 4.5E+09 5.0E+09 AM13279v1 AN4148 5 Reference Reference 1. SPIRIT1 datasheet 2. ARIB STD-T93: “315 MHz band telemeter, telecontrol and data transmission radio equipment for specified low-power radio station” Doc ID 023517 Rev 1 11/13 Revision history 6 AN4148 Revision history Table 3. 12/13 Document revision history Date Revision 06-Aug-2012 1 Changes Initial release. Doc ID 023517 Rev 1 AN4148 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. No license, express or implied, by estoppel or otherwise, to any intellectual property rights is granted under this document. If any part of this document refers to any third party products or services it shall not be deemed a license grant by ST for the use of such third party products or services, or any intellectual property contained therein or considered as a warranty covering the use in any manner whatsoever of such third party products or services or any intellectual property contained therein. UNLESS OTHERWISE SET FORTH IN ST’S TERMS AND CONDITIONS OF SALE ST DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY WITH RESPECT TO THE USE AND/OR SALE OF ST PRODUCTS INCLUDING WITHOUT LIMITATION IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION), OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY RIGHT. UNLESS EXPRESSLY APPROVED IN WRITING BY TWO AUTHORIZED ST REPRESENTATIVES, ST PRODUCTS ARE NOT RECOMMENDED, AUTHORIZED OR WARRANTED FOR USE IN MILITARY, AIR CRAFT, SPACE, LIFE SAVING, OR LIFE SUSTAINING APPLICATIONS, NOR IN PRODUCTS OR SYSTEMS WHERE FAILURE OR MALFUNCTION MAY RESULT IN PERSONAL INJURY, DEATH, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE. ST PRODUCTS WHICH ARE NOT SPECIFIED AS "AUTOMOTIVE GRADE" MAY ONLY BE USED IN AUTOMOTIVE APPLICATIONS AT USER’S OWN RISK. Resale of ST products with provisions different from the statements and/or technical features set forth in this document shall immediately void any warranty granted by ST for the ST product or service described herein and shall not create or extend in any manner whatsoever, any liability of ST. ST and the ST logo are trademarks or registered trademarks of ST in various countries. Information in this document supersedes and replaces all information previously supplied. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners. © 2012 STMicroelectronics - All rights reserved STMicroelectronics group of companies Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Philippines - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States of America www.st.com Doc ID 023517 Rev 1 13/13