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Ambient light sensors are often used in electronic devices with brightness control. Therefore, the luminosity function of the human eye has to be adapted by a semiconductor sensor. This can be realized by a photodiode stack of 3 pn-junctions. The photo-generated currents were combined to a sensitivity response, which is adapted to luminosity function. This concept is verified by numerical simulations...
The determination of ion shares is important for water quality analysis. Most of these analysis are carried out by optical methods or selective probes. Such methods are precise but expensive and mostly not suitable for online measurements because complex devices or chemical substances are needed. The Ca/Mg-ratio is a very important parameter for cleaning equipment like washing machines or dish washers...
Standard indirect learning architecture (ILA) based methods for estimating the parameters in digital pre-distortion produce biased estimates of the parameters due to noise. This paper proposes using a direct model of the power amplifier to generate a noise-free estimate of the output signal and subsequently use this estimated signal to extract the parameters of the pre-distorter using the ILA. Measurement...
This paper presents a localization method based on passive Radio Frequency Identification (RFID). Information that is acquired during the radio information transmission between a tag and the reader is analyzed for this purpose. Resulting parameters allow a statement of the distance between the communication partners. Using several readers with known positions and a motion model of the tags an estimation...
IC Reverse engineering is the process to analyze an integrated circuit to obtain information about its design, materials, logic circuitry, functionality, performance and other relevant features. The increasingly complexity of microchips using a greater number of layers and logic gates makes this process unaffordable when using traditional methods that rely on human inspection and analysis. Therefore,...
Power amplifier (PA) behavior and distortion analysis requires the characterization of the PA nonlinear static input-output relationship, usually evaluated through the input amplitude to output amplitude, AM/AM, response. However, the PA input amplitude to output phase shift, AM/PM, behavior has an equivalent impact on distortion generation, and so it must be also measured. This can be obtained by...
Sensor nodes often have to work for a long time with a single battery. A change of the power source is sometimes not possible or involves effort and costs. If the node needs to be accessible for communication at any point of time it must have a radio in permanent receive state. This depletes the battery in a few days. The contradiction between long lifetime and permanent accessibility can be solved...
The piezoresistive properties of thin films based on carbon nanotubes dispersed in conductive polymer were investigated. Conductive multiwalled carbon nanotubes / Poly (3,4-ethylenedioxythiophene) polymerized with poly(4-styrenesulfonate) (PEDOT:PSS) films were prepared and deposited on flexible polymer substrates (Kapton HN, 250 µm) by drop casting and the aqueous dispersions with different amounts...
In this paper we present our acoustic indoor-localization system ASSIST (Acoustic Self-calibrating System for Indoor Smart phone Tracking) running on embedded ARM CPUs. The developed system uses acoustic signals beyond the audible range to localize COTS (commercial off-the-shelf) smart phones. The sound receivers installed with the infrastructure are connected using a Wi-Fi network. Furthermore, the...
In this paper, two user Cooperation systems based on differential chaos shift keying (DCSK) with orthogonal sub-channel in the broadcast phase and cooperative phase using Walsh code sequence is proposed. Single relay of decode and forward (DF) type is investigated according to the conventional cooperation protocol. A lower bound bit error probability (BEP) is derived and verified by simulation. Independent...
The concept of using rectangular patch resonator (RPR) sensors for microwave characterization of biological materials is the non-invasive nature of the technique. It is being used extensively for the complex dielectric properties measurements of materials in the microwave region. Applications in microwave systems, the dielectric substrate and superstrate are made with low loss materials for the best...
Separate of a high degree of automation in modern factories or production facilities there is a huge demand of addition information to reduce wear or to avoid idle time. Wireless sensor networks provide a more suitable method to gather information in comparison to conventional sensor solutions. Within this contribution requirements for wireless sensor systems will be addressed considering the research...
Issues like production process optimization, monitoring of process parameters, flexibility or production efficiency play an important role for the development of factories or production and logistics facilities in the future. Wireless sensor systems organized in a superordinate network provide more suitable methods for the gathering of additional information in comparison to conventional wired sensor...
This paper presents a wideband GaN Doherty power amplifier (DPA) in the 2.6 GHz band with a 3 stages Wilkinson splitter where the impedance inverter is based on a tapered line instead of a quarter wave transformer. From the comparison with the same amplifier using a typical quarter-wave transformer as impedance inverter, and keeping both designs the same bandwidth (1.6 to 3.3 GHz, 65% of the fractional...
Sign language is the native language of deaf and hearing impaired people which they prefer to use on their daily life. Few interpreters are available to facilitate communication between deaf and vocal people. However, this is neither practical nor possible for all situations. Advances in information technology encouraged the development of systems that can facilitate the automatic translation between...
Despite continuously increasing computing speed of modern calculation clusters, the transient simulation of system models with nonlinear effects is still challenging. This is especially valid in the context of highly complex structures such as MEMS gyroscopes, because of the dramatic increase in calculation time with raising level of detail. Model Order Reduction (MOR) methods such as the modal superposition...
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