Buletinul ştiinţific al Universităţii "Politehnica" din Timişoara. Seria electronică şi telecomunicaţii. Scientific Bulletin of the "Politehnica" University of Timişoara. Transactions on Electronics and Communications Printed: ISSN 1583-3380, Online: ISSN 2344-4444 Vol. 60(74), No. 2, 2015
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Buletinul ştiinţific al Universităţii
"Politehnica" din Timişoara. Seria electronică
şi telecomunicaţii.
Scientific Bulletin of the "Politehnica"
University of Timişoara. Transactions on
Electronics and Communications
Printed: ISSN 1583-3380, Online: ISSN 2344-4444
Vol. 60(74), No. 2, 2015
Editorial Board
• Prof. Dr. Eng. Ioan NAFORNITA, Editor-in-chief
• Prof. Dr. Eng. Virgil TIPONUT • Prof. Dr. Eng. Alexandru ISAR • Prof. Dr. Eng. Dorina ISAR • Prof. Dr. Eng. Traian JURCA • Prof. Dr. Eng. Aldo DE SABATA • Prof. Dr. Eng. Florin ALEXA • Prof. Dr. Eng. Radu VASIU
• Lecturer Dr. Eng. Maria KOVACI, Scientific Secretary • Associate Prof. Dr. Eng. Corina NAFORNITA, Scientific
Secretary
Scientific Board
• Prof. Dr. Eng. Monica BORDA, Technical University of Cluj-Napoca, Romania
• Prof. Dr. Eng. Aldo DE SABATA, Politehnica University of Timisoara, Romania
• Prof. Dr. Eng. Karen EGUIAZARIAN, Tampere University of Technology, Institute of Signal Processing, Finland
• Prof. Dr. Eng. Liviu GORAS, Technical University Gheorghe Asachi, Iasi, Romania
• Prof. Dr. Eng. Alexandru ISAR, Politehnica University of Timisoara, Romania
• Prof. Dr. Eng. Michel JEZEQUEL, TELECOM Bretagne, Brest, France
• Prof. Dr. Eng. Traian JURCA, Politehnica University of Timisoara, Romania
• Prof. Dr. Eng. Ioan NAFORNITA, Politehnica University of Timisoara, Romania
• Prof. Dr. Eng. Mohamed NAJIM, ENSEIRB Bordeaux, France
• Prof. Dr. Eng. Emil PETRIU, SITE, University of Ottawa, Canada
• Prof. Dr. Eng. Andre QUINQUIS, Ministère de la Défense, Paris, France
• Prof. Dr. Eng. Maria Victoria RODELLAR BIARGE, Polytechnic University of Madrid, Spain
• Prof. Dr. Eng. Alexandru SERBANESCU, Technical Military Academy, Bucharest, Romania
• Prof. Dr. Eng. Virgil TIPONUT, Politehnica University of Timisoara, Romania
• Prof. Dr. Eng. Radu VASIU, Politehnica University of Timisoara, Romania
Advisory Board
• Prof. Dr. Eng. Ioan NAFORNITA, Politehnica University of Timisoara, Romania
• Prof. Dr. Eng. Florin ALEXA, Politehnica University of Timisoara, Romania
• Prof. Dr. Eng. Monica BORDA, Technical University of Cluj-Napoca, Romania
• Prof. Dr. Eng. Alexandru ISAR, Politehnica University of Timisoara, Romania
• Prof. Dr. Eng. Radu VASIU, Politehnica University of Timisoara, Romania
Scientific Bulletinul of Politehnica University Timisoara
TRANSACTIONS on ELECTRONICS and COMMUNICATIONS
Volume 60(74), Issue 2, 2015
CONTENTS
Silvia V. Botea: "Analysis of the antenna circuit and its influence on the wheel unit’s RF performance"............................................................................................................................. 3 Camelia Loredana Ţeicu:
"Analysis of RF transceivers used in automotive"........................................................ 8 Cornel Balint, Aldo De Sabata, Septimiu Mischie:
"Ionospheric Propagation Investigation in Western Romania – An Experimental Approach"............................................................................................................................... 14 Ionel Petruţ, Marius Oteşteanu, Cornel Balint, Georgeta Budura:
"Cluster Capacity Increase through eICIC Technology – An Experimental Analysis".................................................................................................................................. 18
Bianca Enache, Marius Otesteanu, Daniel Tiuc:
"Review over different diagnostic specifications and testing tools used in automotive domain"................................................................................................................................... 22 Instructions for authors at the Scientific Bulletin of Politehnica University Timisoara - Transactions on Electronics and Communications ................................................................ 26
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Scientific Bulletin of Politehnica University Timisoara
TRANSACTIONS on ELECTRONICS and COMMUNICATIONS
Volume 60(74), Issue 2, 2015
Analysis of the antenna circuit and its influence on the wheel unit’s RF performance
Silvia V. Botea 1
1 Faculty of Electronics and Telecommunications, Communications Dept. Bd. V. Parvan 2, 300223 Timisoara, Romania, e-mail [email protected]
Abstract – The purpose of this paper is to investigate the performance of the antenna used in the TiS (Tire Information System) module and to find a possible improved solution. A series of simulations of the loop antenna integrated in the TIS module is presented. There are considered 3 different cases: the standalone simulation of the module, the version where the module is placed on the rim, and the last one is the module simulated together with the rim and the tire. The position of the module on the rim and the influences of the tire based on the simulations results are presented by evaluating the impedance and the radiation efficiency. Different dimensions are considered for the rim and the tire. Keywords: TiS, antenna, HFSS
I. INTRODUCTION
TiS (Tire Information System) measures the inflation pressure. The systems developed by Continental permanently monitor the tire's inflation pressure and reliably alert the driver in the event of a loss of pressure. It consists of a central receiver (e.g. remote keyless entry) and four rim modules. The modules measure the current tire pressure, taking into account also the temperature of the tire. In this way, our Tire Information Systems help eliminating a frequent cause of accidents to enhance driving safety. In addition to this, they lower carbon dioxide emissions and reduce fuel consumption. [1] One of the Tire Information Systems designed by Continental Automotive is called TG1C. This product is followed by the TG1D version. The frequencies required by TiS are 315 MHz in the U.S., Canada and Japan and 434 MHz for the rest of the world.
Fig. 1. TG1C product
The physical size of the TG1C module is very restrictive and it is much smaller than the wavelength of interest. As reminded above, the module operates at a frequency of 315 MHz (λ ~ 1 meter) or 434 MHz (λ ~ 0.7 meters). They are usually not structurally self-resonant at these frequencies and have a low radiation resistance and large reactance. In order to improve the radiation efficiency, the module usually utilizes a matching network to cancel the reactance and transform the low radiation resistance to a larger input resistance. [2] For the simulations, the HFSS program has been used. HFSS is a commercial finite element method solver for electromagnetic structures from Ansys Corporation. The acronym stands for High Frequency Structural Simulator (HFSS). It is one of several commercial tools used for antenna design, and the design of complex RF electronic circuit elements including filters, transmission lines, and packaging.
II. EVALUATION OF THE ANTENNA IN THE TIS SENSOR
The module was analyzed in 3 different cases: first in the standalone version, then placed on the rim and lastly placed on the rim and tire. A. Case 1: Standalone antenna structure
The HFSS model used for the analysis is described in the picture below. It is a simplified version used in order to reduce the simulation time. The TG1C module dimensions are: 48 mm x 27.6 mm x 12.5mm (L x W x H). In this case the antenna is placed on the PCB. Also the battery and the housing are present in the simulation. They are modeled after the physical model. In HFSS the antenna is made out of cooper and has a width of 5 mm, a height of 7.3 mm and a total length of 39 mm.
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Fig. 2. TG1C HFSS Model
In Table 1 the real and the imaginary parts of the impedance and the radiation efficiency are shown for both 315 and 434 MHz frequencies. Table 1
Frequency [MHz]
Re Z [Ω]
Im Z [Ω]
Efficiency [dB]
315 0.13 33.40 -18.86
434 0.29 49.36 -16.69
A.1. Antenna on PCB (without housing)
Fig. 3. HFSS model: antenna on PCB (without housing)
First the antenna alone on the ground plane with the battery is analyzed to get a clear image of the housing influence presented in the next paragraph. Below, in table 2, we can see the results. Table 2
Frequency [MHz]
Re Z [Ω]
Im Z [Ω]
Efficiency [dB]
315 0.06 32.07 -15.98 434 0.08 45.30 -12.15
A.2. Antenna on PCB (with housing) In the next 2 figures, the influence of the housing parameters is shown. The relative permittivity and the dielectric loss tangent were taken into consideration. The defaults values, that are currently in use are: r = 3.4, tan = 0.03.
Fig. 5. Efficiency [dB] for TG1C module, with variations of the dielectric loss tangent of the housing between: 0 and 0.05, with a
step size of 0.01
It is clear from figures 4 and 5 that the housing material is very important and it does influence the results. This needs to be taken into consideration when the materials for the series production are chosen. A.3.Analysis of the module position on the wheel The TG1C module is fixed on the rim through the valve. Investigations were made to see if there is possible to find new positions that could lead to better results.
Fig. 6. Efficiency [dB] for different positions of the module along the rim’s width
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B. Case 2: Antenna and rim investigation
Fig. 7. TG1C module and rim HFSS Model
In the table below the results of the simulation of the wheel unit with the rim are presented. There is no direct connection between the module and the rim, the module is placed 8 millimeters above the rim. The rim geometry is based on an actual wheel structure. The module is placed near the location of the tire valve. The metal rim of the wheel plays an important role in the overall performance. We can see in the table below a clear improvement of the efficiency, comparing to the standalone version. The dimension for the rim used in this case is R15 (Table 3). In figure 8, a variation of the rim dimensions is shown and the way it influences the efficiency. Table 3
Fig. 8. Efficiency [dB] for TG1C module, with variations of the
rim dimensions between: R14 and 20, with a step size of 1
C. Case 3: Antenna, rim and tire investigation
Fig. 9. Component parts of the tire
Between the tread inner liner and outer rubber there is a simplified metal steel belt.
Fig. 10. TG1C HFSS model: the module, the rim and tire section For the investigation of the antenna together with rim and tire, the following tire configurations were used in simulation: 175/70/R14, 195/65/R15, 215/55/R16, 215/50/R17, 235/40/R18, 235/55/R19, 255/50/R20. Below, in figure 11, the results are presented. It can be seen that there are some maximum efficiency points. The values at 315 and 434 MHz are highlighted.
III. 3. POSSIBLE IMPROVEMENTS IFAs (Inverted F Antenna) usually have a very good behavior with gain values that ensure adequate performances taking into account the standard values of the output power and receiver sensitivity of short range radio devices. That is why I investigated a new possible improved solution consisting in an IFA antenna. Below, in fig. 12, it is pictured the HFSS model. A simplified housing was used for the investigations. The height of the antenna is 7 mm.
Fig. 12. TG1C HFSS model: IFA antenna
Next, the performances of this antenna are shown. The efficiency comparing to the loop antenna is increased and when increasing the length of the antenna even better performances should be obtained. Further investigations with this antenna placed on the rim and including the tire still need to be made to see if it could lead to a better behavior in all cases. Also, the dependence and stability of the antenna parameters is very important and needs to be analyzed. Table 4
Frequency [MHz]
Re Z [Ω]
Im Z [Ω]
Efficiency [dB]
315 0.07 25.13 -18.40
434 0.09 35.30 -14.85
A comparison between the TG1C with loop antenna and the module with the IFA is presented. They were only compared in the standalone version. The graphs below are only for 434 MHz frequency.
Fig. 13. Comparison between loop antenna and IFA antenna: gain total, xz plane
Fig. 14. Comparison between loop antenna and IFA antenna: gain total, yz plane
Fig. 15. Comparison between loop antenna and IFA antenna: gain total, xy plane
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IV. MATCHING NETWORK Antenna’s input impedance is strongly dependent on the environment. If metallic parts or even dielectric bodies are positioned close to the antenna, a strong mutual coupling between antenna and the environment can appear. Typically ‘close’ means a distance less than λ/10 (λ is the free space wavelength at operating frequency) between the antenna and a metallic or a dielectric body. The coupling is strongest in the case of metallic bodies. In order to improve the efficiency TIS antennas utilize a matching network to cancel the reactance and transform the low radiation resistance to a larger input resistance. [3] For maximum power transfer to the antenna we use a certain matching topology. This matching is filtering the harmonics and favoring the fundamental frequency. It is made from LC components with small tolerances. For each PCB supplier it is necessary to redesign the matching accordingly.
V. CONCLUSIONS Automotive industry is in a continuous and very quick development and so are the radio systems integrated in the cars. This paper tries to show how to do an
investigation on the parameters that influence the antenna performance of the TG1C module. These results are used for future improvements of the new products that are developed. Some other investigations with a IFA antenna and were made, but so far the loop antenna was kept on the module because of better stability of electrical parameters. The purpose is to improve the overall performance. Further investigations can still be made in order to find the best solution. From November 2012 it is mandatory that all new cars produced in EU are equipped with the tire information system, so we get the conclusion that this is an important car service and a lot of engineering in the development process is needed to introduce on the market new improved solutions.
VI. REFERENCES [1] Continental website: http://www.conti-online.com/www/automotive_de_en/themes/passenger_cars/interior/body_security/pi_tire_information_en.html [2] Hua Zeng and Dr. Todd Hubing, Technical Report: CVEL-10-023, Investigation of Antennas used in Tire Pressure Monitoring Systems, 2010 [3] F. Lathiere, Synthesis of measurements and simulations for ITEMS WU positioned in wheel, Continental intern, 2011
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Scientific Bulletin of Politehnica University Timisoara
TRANSACTIONS on ELECTRONICS and COMMUNICATIONS
Volume 60(74), Issue 2, 2015
Analysis of RF transceivers used in automotive
Camelia Loredana Ţeicu1
1 Faculty of Electronics and Telecommunications, Communications Dept. Bd. V. Parvan 2, 300223 Timisoara, Romania, e-mail [email protected]
Abstract – The paper presents the redesign of a radio frequency (RF) front-end transceiver used in automotive as part of the remote keyless entry (RKE) and tire-pressure monitoring (TPMS) system. The redesign must keep the same RF performances or improve them in some cases. A practical impedance analysis is done to choose the best design in terms of performance versus costs for reception and transmission. Comparative measurements for the main characteristics, on the RF transceiver board, before and after the redesign, were realized to confirm the obtained performances. Keywords: RKE, TPMS, transceiver, SAW filter
I. INTRODUCTION
Short-range radio systems designed to work in unlicensed industrial, scientific, and medical (ISM) bands between 300MHz and 928MHz use as key components the low-cost FSK and/or ASK transceiver ICs. Applications for these short-range devices (SRDs) include remote keyless entry and tire-pressure monitoring systems. Remote keyless entry is very popular in the new vehicles, because beside the advantages for comfort this technology minimizes the risk of theft. The new generation of RKE systems is capable to inform the users what is the status of the vehicle: if the doors are not locked or if needs more gas. [1] The tire-pressure monitoring system (TPMS) is more and more requested by the automotive producers as well, because is increasing the safety of the driver and the efficiency of the driving. There are two types of TPM: indirect or direct. The direct TPM is more precise and easy to use than the indirect TPM, which is using the speed sensors from the anti-lock braking system (ABS). [2] A. RF transceiver
In this paper, the RF transceiver is operating in two ISM bands used in Europe, 434MHz for TPM and 868MHz for RKE. The transceiver unit (Fig.1.) consist of an internal antenna, an RFIC, matching for the transmit frequency for communication to remote unit (key), matching for RKE and TPMS receive frequencies, a micro controller (µC), a voltage regulator, a temperature sensor for a dynamic frequency compensation, a ISO9141/LIN transceiver, an
external power amplifier and a wiring connector for communication interface and power supply. For RKE messages, a two-frequency agility function will be used, which means that the first part of a transmission is at one frequency f1 (868.05MHz) and the other within 2 MHz at f2 (868.55MHz). Another receive path with matching to a second frequency band f3 (433.92MHz) used for TPMS messages will be achieved by HW-switches controlled by the µC.
Fig. 1. Block diagram for RF transceiver
The transceiver unit receives a radio signal from the corresponding transmitting unit and demodulates it. Then will analyze if the received signal is containing a valid RF data. B. RF transceiver characteristics
Sensitivity is defined as the minimal signal level
which can be properly received and demodulated by the receiver at the required bit error rate. [3]
Sensitivity bandwidth is defined as the frequency spread between the half-power (3dB) points on the receiver response curve.
Co-channel rejection measures the receiver’s ability to receive the wanted signal in the presence of an unwanted signal at the same frequency. The limit for this RF transceiver is at +11dB S/N ratio.
Adjacent channel rejection measures the receiver’s ability to receive the wanted signal in the presence of interference at an adjacent channel. Each channel has two adjacent channels, lower and upper, with certain channel spacing. This rejection must be bigger than 30dB.
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Image frequency suppression is the ratio between the sensitivity for a signal at the image frequency to the sensitivity in the wanted channel. The RF transceiver must have a ratio bigger than 40dB.
Dynamic range is an important performance characteristic. The dynamic range sets the maximum and minimum limits of the signal level which can be properly processed by the transceiver. The minimum limit is defined by the sensitivity level, whereas the maximum limit will be determined by the receiver’s capability of processing the high signal level linearity.[3]
The in-band selectivity (within fchannel±1MHz) is a measure of the receiver’s capability to detect a certain modulated signal without exceeding a given degradation due to the presence of an unwanted (un-modulated) signal within the reception band.
Output power is the transmitting power level at a certain frequency, required for a good reception and decoding of the signal at the receiving unit.
Harmonics are component frequencies of the signal that is an integer multiple of the fundamental frequency. These must be reduces in order to be in line with the radio regulations. Because the transmit channels are in the 868MHz ISM band, only the first two harmonics are measured.
These are the main characteristics, but there are others, amongst: desensitization out-of band, spurious response in-band/out-of-band, intermodulation rejection 3rd order, LO leakage, spurious emissions, adjacent channel power and occupied bandwidth.
II. REDESIGN OF THE RF TRANSCEIVER
Due to evolution of technology and the increasing market, components suppliers tend to improve their products by releasing other models for the same component. This improvement can be the quality of the product or just to reduce the costs for production. Therefore there is a constant need in automotive to redesign specific modules to be compliant with other components. In the present paper, the RF transceiver has two surface acoustic wave (SAW) filters, for reception, which can select between the RKE and TPM bands. These SAW filters, namely B3762 and B3780, have 8 pins and will no longer be produced, but replaced by B3744 and B3936 filters. This requires the transceiver to be redesigned. Redesigning includes also a printed circuit board (PCB) supplier replacement and a layout change, because the new SAW filters have 6 pins with different configuration than the previous versions. A. Analysis in impedance for reception
First step in designing a matching network for SAW filters is to measure on the board the insertion loss and the selectivity of the filters, but also the S11 and S22 parameters to see the reflection at port 1 or at port 2.
Best way to optimize the matching is to look in impedance at S11 and S22 parameters, because this two need to be close and with the same shape in a frequency span. Thus, the part to part distribution can be reduced. The measurement setup consists of a vector network analyzer (VNA) and cables soldered at specific test points on the board. The vector network analyzer must be initially calibrated and an offset for the cables must be introduced. The impedance analysis implies the practical measurements of the matching for the two SAW filters, each in five configurations: 1. the old SAW filter with the corresponding
matching; 2. the new SAW filter with the old matching; 3. the new SAW filter with the matching specified
by the filter producer in the datasheet; 4. the new SAW filter with a 50Ω optimized
matching; 5. the new SAW filter with the final matching,
which will be implemented with the redesign. The matching schematics were done in Microwave Office, which is a software used for RF design and simulation. The first configuration has the matching in a π topology for RKE band (Fig. 2.) and an L topology for TPMS band (Fig. 3.):
Fig. 2. Old SAW filter with the actual matching for RKE band
Fig. 3. SAW filter with the actual matching for TPMS band
Prior to redesign, the transceiver has good performances for reception in both bands. The configurations from Fig. 2 and Fig. 3 have the impedance at channel frequencies shown below (Fig. 4-7). The markers are at 868,05MHz and 868,55MHz for RKE band, and at 433,92MHz for TPMS band.
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0 0.2 0.5 1 2 5 10
-5
-2
-1
-0.5
0.5
1
2
5
CH1 1 U
FIL10k10kFIL10k10k
CPL
OFS
CAL
CENTER 868 MHz SPAN 50 MHz
S11
1
2
2: 28.09 -j5.694
868.55 MHz
1: 34.11 j9.556
868.05 MHz
Fig. 4. S11 parameter for Fig. 2 configuration
0 0.2 0.5 1 2 5 10
-5
-2
-1
-0.5
0.5
1
2
5
CH2 1 U
CENTER 868 MHz SPAN 50 MHz
FIL10k10kFIL10k10k
CAL
CPL
OFS
S22
12
2: 45.59 j12.56
868.55 MHz
1: 83.26 j14.15
868.05 MHz
Fig. 5. S22 parameter for Fig. 2 configuration
0 0.2 0.5 1 2 5 10
-5
-2
-1
-0.5
0.5
1
2
5
CH1 1 U
CENTER 433.92 MHz SPAN 50 MHz
FIL10k10kFIL10k10k
CPL
OFS
CAL
S11
1
2
2: 46.56 j14.75
433.97 MHz
1: 42.63 j24.17
433.92 MHz
Fig. 6. S11 parameter for Fig. 3 configuration
0 0.2 0.5 1 2 5 10
-5
-2
-1
-0.5
0.5
1
2
5
CH2 1 U
CENTER 433.92 MHz SPAN 50 MHz
FIL10k10kFIL10k10k
CPL
OFS
CAL
S22
1
2
1: 52.32 j16.77
433.92 MHz
2: 50.24 -j10.25
434.01 MHz
Fig. 7. S22 parameter for Fig. 3 configuration
Fig. 8. New SAW filter for RKE band, B3744 with the old
matching
Fig. 9. New SAW filter for RKE band, B3936 with the old matching
Fig. 10. S11 parameter for Fig. 8. configuration
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Fig. 11. S22 parameter for Fig. 8. Configuration
Fig. 12. S11 parameter for Fig. 9. configuration
Fig. 13. S22 parameter for Fig. 9. configuration
The second configuration analyzed (Fig. 8-9) shows good results for the RKE SAW filter, but for the TPMS SAW filter the performances are worse than the old ones. There can be noticed (Fig. 10-13) the PCB and layout influence and the new SAW filters characteristics. The third and the fourth configurations were done in order to see if the filter’s producer recommendations are reproducible on every type of PCB and how much improvement the matching brings. Finally, for RKE SAW filter it was decided to keep the second configuration, because the sensitivity at channels frequencies is still compliant with the requirements and there’s no need to change the components, resulting in a cost reduction for this redesign. For the TPMS SAW filter, the final matching is presented in fifth configuration, that is the filter producer matching, but without one capacitor, to keep the same number of components in the bill of materials (BOM). In this case, a compromise was made, because the old way of doing the matching of the filter is not relevant due to the fact that the whole reception part has new impedances along the traces and at the test points there is no more a 50Ω impedance. So the solution to decide which is the best matching configuration is to measure the reception sensitivity. An overview based on the measurements done for the five matching configurations is presented below (Table 1). We can see also the measurements done for the selectivity of the SAW filters. Table 1. Matching configurations results
B. Analysis in impedance for transmission
Because this is a redesign, the target is to keep at least the same performances. A solution is to compare the load impedance that the integrated power amplifier needs for best operation. In the transmission part, only the PCB is replaced. The expectations are that the influences of the PCB stack-up to be small since the new stack-up has the same configuration with the old one. The load impedance at the PA is measured on the transceiver with a VNA, when the RFIC is disconnected, the active components are on and the
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HW-switch is controlled for transmission, which leads to a 50Ω termination instead of the antenna. Before the redesign, the load impedance measured at the integrated PA is 18,53 + j29,13Ω at 868.05MHz and 18,59 + j29,26Ω at 868.55MHz (Fig. 14).
0 0.2 0.5 1 2 5 10
-5
-2
-1
-0.5
0.5
1
2
5
CH1 1 U
FIL10k10kFIL10k10k
CPL
OFS
CAI
START 680 MHz STOP 1.2 GHz
M
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1: 18.53 j29.13
868.05 MHz
2: 18.59 j29.26
868.55 MHz
Fig. 14. Load impedance at the integrated PA before redesign
After the redesign, the load impedance measured at the integrated PA is 20.74 + j27,5Ω at 868.05MHz and 20,79 + j27,66Ω at 868.55MHz (Fig. 15). The difference is small, only 2Ω in the real part. In this case, nothing else is modified in the matching. The transmitter characteristics will remain the same and the output power is already calibrated on the production line, by increasing the gain and power steps of the PA.
0 0.2 0.5 1 2 5 10
-5
-2
-1
-0.5
0.5
1
2
5
CH1 1 U
FIL10k10kFIL10k10k
CPL
OFS
CAI
START 680 MHz STOP 1.2 GHz
M
12
1: 20.74 j27.50
868.05 MHz
2: 20.79 j27.66
868.55 MHz
Fig. 15. Load impedance at the integrated PA after redesign
III. MAIN CHARACTERISTICS MEASUREMENTS
In this section, the main characteristics of the RF transceiver are measured to see if the RF performance is still compliant with the design before the redesign. For these measurements two boards were used to compare the results before and after redesign. But for
a design validation, more samples must be measured to see the part to part distribution, due to components tolerances and other small influences. A. Setup configuration
The setup (Fig. 16) must simulate the corresponding RKE remote unit and the TPMS sensor and also to provide the interference signal for the tests.
Fig. 16. Test setup configuration
The measurements involve the application of the RF signal at the 50Ω reference by disconnecting the antenna matching and inserting a coaxial cable. The transceiver is inside the shielded box, where it is powered with 12V and the response on the ISO9141 is monitored with the PC. The PC also commands the trigger box and all the generators. The RF parameters corresponding to every type of telegram are introduced with a specific application on the PC. The test setup is calibrated on each frequency, so the attenuation inserted by the cables can be correlated in the results. For output power and harmonics measurement a spectrum analyzer and a 20dB attenuator were included in the setup. B. Comparative results
The following main characteristics were measured with the setup presented above: sensitivity at center frequency for each channel, sensitivity bandwidth, image frequency suppression, adjacent channel rejection, co-channel rejection, in band selectivity, dynamic range, output power and harmonics. A summarized table is presented below (Table 2): Table 2. Comparison of measured characteristics before and after redesign
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The measuring method is very important as it can have significant influence on the results. A short description of every measurement is explained below: Sensitivity at center frequency: the power level is
adjusted until the sensitivity limit is reached. Sensitivity bandwidth: the frequency will be
sweep in a 300 kHz span, with 5 kHz step. For each step the power level is adjusted until the sensitivity limit is reached. The frequency and power level are recorded.
Image frequency suppression: the same signal is applied at center frequency and at image frequency. The sensitivity is measured for each frequency and recorded. The difference between sensitivities is the image frequency suppression.
Adjacent channel rejection: the signal is set at center frequency fc and the FM interference is set first at fc-channel spacing and then at fc+channel spacing. The S/N is recorded.
Co-channel rejection: the signal is set at center frequency fc and the FM interference is set at same frequency. The S/N is recorded.
Selectivity in band fc±1MHz: the signal center frequency is set at channel frequency and the continuous wave (CW) interference is swept in a 2MHz span, with 25 kHz step. S/N is recorded.
Dynamic range: the signal set at center frequency will be increased from -120dBm to 0dBM with 10dB steps. The errors are recorded at each step.[4]
Output power and harmonics: the transceiver is put in transmitting mode, and the power level is measured with the spectrum analyzer.
Fig. 17. Selectivity in band for first RKE channel
Fig. 18. Selectivity in band for second RKE channel
Fig. 19. Selectivity in band for TPMS channel
The results after the redesign are close to the old design, only the sensitivity is improved with around 2dB for the RKE channels (Fig. 17-18). This proves that the RF performance is still compliant with the transceiver requirements.
IV. CONCLUSIONS
The paper presents a redesign of an RF transceiver front-end used in automotive, dual band and dual channel system. It is important to have at least same performance as initial even if the technology is evolving, and the main components must be changed. In this case, the SAW filters used for reception and the PCB supplier changed. The introduction of these new components is analyzed in impedance for reception and transmission to see the effects and compensate them. Also the main characteristics and the way they are tested are presented to prove the performance conformity with the old design. It can be observed that the solution for redesign is better in some cases than the old one, but only because the cumulative effect of the filter’s matching and the new PCB layout helps. The conclusion is that after each change in the RF area, the design need to be adjusted. There is no one by one replacement for any component used in the front-end of the transceiver. Impedance can be easy shifted if any of the elements between antenna and RFIC is modified.
V. REFERENCES
[1] *** AN3589 Power Amplifier Theory for High-Efficiency Low-
[4] C.L. Teicu, „Analiza Transceiverelor de RF Utilizate in Industria Automotive” Master Thesis, Politehnica University Timisoara June 2014.
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Buletinul Ştiinţific al Universităţii Politehnica Timişoara
TRANSACTIONS on ELECTRONICS and COMMUNICATIONS
Volume 60(74), Issue 2, 2015
Ionospheric Propagation Investigation in Western
Romania – An Experimental Approach
Cornel Balint1 Aldo De Sabata
2 Septimiu Mischie
3
1 Faculty of Electronics and Telecommunications, Communications Dept.
Bd. V. Parvan 2, 300223 Timisoara, Romania, [email protected] 2 Faculty of Electronics and Telecommunications, Measurement and Optical Electronics Dept.
Bd. V. Parvan 2, 300223 Timisoara, Romania, [email protected] 3 Faculty of Electronics and Telecommunications, Measurement and Optical Electronics Dept.
[8] Md. Shipon Ali, “An Overview on Interference Management in
3GPP LTE-Advanced Heterogeneous Networks“, International
Journal of Future Generation Communication and Networking,
Vol. 8, No. 1, 2015, pp. 55-68.
[9] A. Daeinabi, K. Sandrasegaran, “A Proposal for an Enhanced
Inter-Cell Interference Coordination Scheme with Cell Range
Expansion in LTE-A Heterogeneous Networks”, Workshop on
Advances in Real-time Information Networks, 7-10 aug., 2013,
[10] I. Petrut, M. Otesteanu, C. Balint, G. Budura, “HetNet
handover performance analysis based on RSRP vs. RSRQ triggers”
38th International Conference on Telecommunications and Signal
Processing (TSP), 2015, 9-11 July 2015, Prague, pp. 232 – 235.
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Scientific Bulletin of Politehnica University Timisoara
TRANSACTIONS on ELECTRONICS and COMMUNICATIONS
Volume 60(74), Issue 2, 2015
Review over different diagnostic specifications and testing tools used in automotive domain
Bianca Enache1 Marius Otesteanu2 Daniel Tiuc3
1 Faculty of Electronics and Telecommunications, Communications Dept. Bd. V. Parvan 2, 300223 Timisoara, Romania, e-mail [email protected] 2 Faculty of Electronics and Telecommunications, Communications Dept. Bd. V. Parvan 2, 300223 Timisoara, Romania, e-mail [email protected] 3 Faculty of Mechanics, Industrial Dept. Bd. V. Parvan 2, 300223 Timisoara, Romania, e-mail [email protected]
Abstract – This paper presents a review over the most popular tools used in automotive industry for black-box testing process. It presents the benefits of diagnostic specifications and diagnostic testers. It also reflects how important is to have a template that can satisfy any diagnostic data. Index Terms—testing, tools, automotive, diagnostics, requirements.
I. INTRODUCTION
The vehicle functionality is in continuing research. The entire system functionality is tested using black-box testing. This testing type verifies the system behavior using an input-actions-output model. It is seen as an opaque system, without any interest about the interior. It is checked that for a set of inputs, applying a set of actions, is obtained a set of outputs according to the requirements. Some of the tools that are used in automotive domain at system test level for diagnostic are[3]: CANdelaStudio, ODXStudio, CANoe.Diva, Indigo, CANoe, CANape, vFlash. The CANdelaStudio is used to specify the diagnostic features of an ECU, while the ODXStudio is used for ant ODX category of ASAM ODX 2.0.1. or ISO ODX 2.2. For an automated environment the ECU diagnostic software validations is performed using CANoe.DiVa, CANoe, Indigo and CANape. Here the Electronic Control Unit (ECU) test cases are generated and the execution process is automated entirely or half. The vFlash tool is very efficient and user friendly to flash over Controller Area Network (CAN), Local Interconnect Network (LIN) or Ethernet.
II. THE DIAGNOSTIC TOOLS OVERVIEW
In this chapter each tool will be treated separately. It will be proved the impact of it in the daily job of a system test engineer.
The first one, CANoe.Diagonostic Integration and Validation Assistant(CANoe.DiVa) represents one of the ways for obtaining automated and data based generation of test cases that can be reproduced. It can be considered the link between CANdela and CANoe. It generates some automated ECU specific test module for CANoe using diagnostic requirements. From standards point of view this tool supports[5]: ISO 14229 Unified Diagnostic Services (UDS): 2006/2013, ISO 15765 Diagnostics on CAN, ISO15031/J1979 On Board Diagnostics, etc. Another feature of CANoe.Diva is represented by the modality of mapping the customer or system requirements to test cases results. Using DOORS for storage the customer requirements for instance the CANdelaStudio tool can facilitate the import and export process. It is able to generate requirements from diagnostic information and diagnostic information from requirements. In order to access the vehicle system through UMTS/GPRS the Indigo tool can be used. It will be discussed in the next chapter. The vFlash tool is coming with the possibility to flash in parallel 8 ECUs.
III. DIAGNOSTIC CONCEPT USING REQUIREMENTS
Each customer is unique and in order to cover all the needs the diagnostic information is combined in such a manner to be customized easily[1].
Fig. 1. The diagnostic data template
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Creating a template where information coming from different sources like ISO standards that were already mentioned in chapter II, customer specifications, different diagnostic functions defined and assigned to protocols and nevertheless general diagnostic information that are available in this domain to all ECUs, allows supplier to easily customize the projects to an XML. For instance if this template is applied to CANdela files like in Fig.2:
Fig. 2. The description functionality for a specific ECU
The authoring diagnostics for a specific ECU can be defined as in Fig. 3 where an ECU description is performed. Then is defined a diagnostic class where are presented all the sessions that are supported, the internal or external key access for security access, the Diagnostic Trouble Code(DTC), variant coding if it’s suitable for many continents and ECU reset like software reset and hardware reset. Each class has different diagnostic use cases as the one presented above[1].
Fig. 3. The authoring diagnostics for a specific ECU
Each ECU besides positive responses has negative response codes (NRCs), variants, data types and different states. In order to have a better overview in Fig. 4 is taken an example of states and states transitions of diagnostic services based on ISO 14229-UDS.
Fig. 4. States and state transitions for a specific ECU
In Fig. 4 are represented 3 sessions: default, extend and programming. For each of it were represented their dependencies[2]. Another example can be considered in Fig.5. Here can be observed how DTCs can be imported or exported in other formats and also the amount of information about a specific DTC:how a DTC is performed, how can you read it according to your interest etc.
Fig. 5. Diagnostic instance for a specific ECU
In this way the CANdela Studio became and it’s considered an interface with DOORS requirements. The type of the requirements can be the same as in DOORS: text only, heading, DTC description etc. Each requirement has an unique ID, which is very important especially for import or export activities. One of the most important features is represented by the exchange between different tools form different providers, in this case: CANdela and DOORS. For user interface point of view another user-friendly tool is CANoe DiVa. It allows you to configure test cases according to your needs and imagination. At the end of execution you have a detailed and very well structured report, which can help you as a tester to perform the analysis. The system test engineer can select what to test from a single test case to a group of them (Fig.6 and Fig.7). The diagnostic message flow can be physical or functional. It also offers you data type checks, sessions and security levels, parameters validation against diagnostic values.
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Fig. 6. Test report overview for a specific test case
Fig. 7. Test report overview for a group of test cases
CANoe.Diva reflects the possibility to link the test cases with the requirements. Also offers the possibility to have a requirement overview and requirement view for test analysis. One of the most important benefits is that it offers excellent test coverage, it’s efficient and can generate automated test without user interaction. All development stages supported and significant savings of time and effort. This tool can be used with other hardware tools (e.g. VT System) in order to perform different short-circuits (e.g Short to Ground). While the tools presented above were for diagnostic specifications, the testers can choose different tools for diagnostic tests according to their needs[4]. For instance they can select CANoe, CANape or Indigo(Fig.8-10).
Fig. 8. The CANoe interface
Fig. 9. The CANape interface
Fig. 10. The Indigo interface
All three tools allow the possibility to insert CAPL test Module, .NET Test Module or XML Test Module. In this way all the scripts developed by the tester using one of the application can be entirely reused in other application (CANoe, CANape, Indigo). This is possible due to a library that provides a way to create and send diagnostic request, or share procedures between tools[4]. If CANoe and CANape are very used in automotive industry, a point of interest comes from another tool called Indigo.
Fig. 11. Accessing a vehicle remote
Intelligent Diagnostic Test System (INDIGO) is self-configuring and vehicle oriented. It is capable of diagnosing vehicle components, executing special tasks (scripting) or creating individual configurations. It is made in order to be user-friendly not only for engineers, but also for technicians due the fact that it can apply a diagnostic to vehicle during a test-drive. The process of applying diagnostics remotely by Indigo is presented in Fig.11. This process can be performed via Internet using UMTS/LAN/WLAN. It
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assumes to work for low data traffic and high security. The remote access can be done using a Windows tablets[4].
IV. CONCLUSIONS The tools that were presented are user-friendly not only from engineers point of view, but also from customers and are very popular in automotive industry nowadays. All are based on multi-brand solution, by using one architecture for many other brands. The testers can configure as much as they wish and can be linked between them.
ACKNOWLEDGMENT This paper is supported by the Sectoral Operational Programme Human Resources Development
POSDRU/159/1.5/S/137516 financed from the European Social Fund and by the Romanian Government. This work was partially supported by the strategic grant POSDRU/159/1.5/S/134378 (2014) of the Ministry of National Education, Romania, co-financed by the European Social Fund – Investing in People, within the Sectoral Operational Programme Human Resources Development 2007-2013.
REFERENCES [1] http://vector.com/vi_diagnostics_en.htmlaccessed :23.08.2015 [2] http://vector.com/vi_training_en.html accessed : 24.08.2015 [3] http://vector.com/vi_portfolio_en.html accessed: 25.08.2015 [4] http://vector.com/vi_diag_tester_en.htmlaccessed:24.08.2015 [5] Verband der Automobilindustrie, Quality management in the Automotive Industry Quality Assurance of Supplies, VDA and QMC,2004.
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Scientific Bulletin of Politehnica University Timisoara
TRANSACTIONS on ELECTRONICS and COMMUNICATIONS
Volume 61(75), Issue 1, 2016
Instructions for authors at the Scientific Bulletin of the Politehnica University of Timisoara - Transactions on
Electronics and Communications
First Author1 Second Author2
1 Faculty of Electronics and Telecommunications, Communications Dept. Bd. V. Parvan 2, 300223 Timisoara, Romania, e-mail [email protected] 2 Faculty of Electronics and Telecommunications, Communications Dept. Bd. V. Parvan 2, 300223 Timisoara, Romania, e-mail [email protected]
Abstract – These instructions present a model for editing the papers accepted at the Scientific Bulletin of “Politehnica” University of Timisoara, Transactions on Electronics and Communications. The abstract should contain the description of the problem, methods, solutions and results in a maximum of 12 lines. No references are allowed here. Keywords: editing, Bulletin, author
I. INTRODUCTION
The page format is A4. The articles must be of 6 pages or less, tables and figures included.
II. GUIDELINES
The paper should be sent in this standard form. Use a good quality printer, and print on a single face of the sheet. Use a double column format with 0.5 cm in between columns, on an A4, portrait oriented, standard size. The top and bottom margins should be of 2.28 cm, and the left and right margins of 2.54 cm. Microsoft Word™ for Windows is recommended as a text editor. Choose Times New Roman fonts, and single spaced lines. Font sizes should be: 18 pt bold for the paper title, 12 pt for the author(s), 9 pt bold for the abstract and keywords, 10 pt capitals for the section titles, 10 pt italic for the subsection titles; distance between section numbers and titles should be of 0.25 cm; use 10 pt for the normal text, 8 pt for affiliation, footnotes, figure captions, and references.
III. FIGURES AND TABLES Figures should be centered, and tables should be left aligned, and should be placed after the first reference in the text. Use abbreviations such as “Fig.1.” even at the beginning of the sentence. Leave an empty line before and after equations. Equation numbering should be simple: (1), (2), (3) … and right aligned:
∫− −=a
adtytx ττ )()( . (1)
IV. ABOUT REFERENCES References should be numbered in a simple form [1], [2], [3]…, and quoted accordingly [1]. References are not allowed in footnotes. It is recommended to mention all authors; “et al.” should be used only for more than 6 authors. Table 1
Parameter Value Unit I 2.4 A U 10.0 V
V. REMARKS A. Abbreviations and acronyms Abbreviations and acronyms should be explained when they appear for the first time in the text. Abbreviations such as IEEE, IEE, SI, MKS, CGS, ac, dc and rms need no further explanation. It is recommended not to use abbreviations in section or subsection titles.
Fig. 1. Amplitudes in the standing wave
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B. Further recommendations The International System of units is recommended. Do not mix SI and CGS. Preliminary, experimental results are not accepted. Roman section numbering is optional.
REFERENCES [1] A. Ignea, “Preparation of papers for the International Symposium Etc. ’98”, Buletinul Universităţii “Politehnica”, Seria Electrotehnica, Electronica si Telecomunicatii, Tom 43 (57), 1998, Fascicola 1, 1998, pp. 81. [2] R. E. Collin, Foundations for Microwave Engineering, Second Edition, McGraw-Hill, Inc., 1992. [3] http://www.tc.etc.upt.ro/bulletin