Mervin T. Hutabarat

The effect of bias and load impedance to non linearity characteristics of RF LD-MOSFET

LD MOSFET as large signal RF power amplifier has been characterized and modeled for high power and broadband RF amplifier. Large signal model has been derived and verified based on I–V characteristics and S-parameter data. Non-linier model has been used to model LD MOSFET large signal characteristics. Good fit of measured and simulation results of LD MOSFET I–V characteristics as well as S-parameter curves verified large signal model and extracted model parameters. The effect of transistor biases, V<inf>GS</inf> and V<inf>DS</inf> to 2nd (IM2) and 3rd order (IM3) intermodulation distortion of LD-MOSFET (D2081UK) relative to fundamental output power have been obtained and verified. Highest level of IM3 was shown at V<inf>GS</inf> = 1,6 V near threshold voltage (V<inf>TH</inf> = 1,4 V) and minimum level of IM3 at V<inf>GS</inf> = 2 V, at input power, P<inf>in</inf>, of −30 dBm and load impedance, R<inf>L</inf> = 50 Ω. While the effect of V<inf>DS</inf> shows maximum of IM3 at knee voltage and declining level at higher V<inf>DS</inf>. The effect of varying load impedance, R<inf>L</inf>, to IM3, IM2 and fundamental levels has shown minimum dip of IM3 at R<inf>L</inf>= 31 Ω with gradual increase as load increasing above 50 Ω. The intersection point of 3rd order intermodulation (IP3) at V<inf>GS</inf> = 2.2V shows higher power level of IP3=50dBm with input power of 18dB than level at V<inf>GS</inf> = 1.8V with IP3 of 46dBm. This behaviour of non-linearity effect of the transistor was verified and evaluated based on the large signal model of LD MOSFET device. Analysis of non-liniearity behavior based on LD MOSFET device structure and physics was carried out in comprehending the origin of non-linearity and in the implementation of linearization method.

Microcontroller-based Transcutaneous Electrical Nerve Stimulator with 8 bit cascade DAC

Transcutaneous Electrical Nerve Stimulator (TENS) is one of medical instrument that use electricity to stimulate the nerve and produce analgesic effect. This microcontroller-based TENS is designed with AT89S8252 as signal generator and OPA2544T to provide voltage conversion. Two 8-bit DAC with cascade configuration that is used in this design gives significant decrease to product cost. This prototype not yet tested for clinical use.

Product service system: Design of E-commerce solutions to parking space optimization using bluetooth technology

How long you are looking for a parking lot? Have you ever forgotten where you parked your car? In this paper is under way to develop an innovative parking management tool relying on E-commerce Solutions to Parking Space Optimization (ESPSO) using Bluetooth technology. ESPSO with Bluetooth technology believed would solve these problems. In this paper ESPSO services are packed in the concept of Product-Service System (PSS). PSS are system solutions that directly fulfil client demands with a combined set of products and services. The PSS concept applied in this ESPSO has the potential to improve ESPSO competitiveness and provide for new continuous quality improvement in parking system opportunities. Improvement is one of the purposes of quality in ESPSO applied which packed in the concept of PSS; the other main purposes are accountability, control and compliance. This PSS concept if compared with conventional products sales offers, substantial differences can be found. In the case of the typical product sales model, producing and selling products is the primary method to meet client demands, regardless of the type of actual demands. The invention of the ESPO is characterized in that since said time recording machine and mobile telephones are equipped with short-distance communication (Bluetooth) and also the PSS concept applied in this system. In reaching this goal, the innovative solutions seek to benefit all social segments, to optimize existing parking resources, and to contribute to achieving a more sustainable urban transport, reducing congestion and pollution. For the PSS concept applied in this ESPSO has the potential to minimize environmental impacts of both production and consumption is emerging.

An emulation of transparent interface design based on TCP/IP implemented onto FPGA of an Altera Nios® Board

A TCP/IP-based interface design has been designed, and the interface can process data based on the Ethernet IEEE 802.3 Standard. This interface is able to identify Ethernet Frame IEEE 802.3, Header of LLC 802.2, Header and the Packet Data of IP Datagram. In addition, the interface can perform simple encryption process, and renew FCS (Frame Check Sequence) data of an ethernet frame. After the interface design had been simulated, it was implemented onto Altera Stratix EP1S10F780C6ES FPGA of an Altera Nios® Board. The interfaces synthesis result shows that the interfaces internal frequency is up to 78.01 MHz. Moreover, the implementation result was verified using SignalTap II Logic Analyzer. The interface functions as an emulator properly which can operate in half duplex mode.

Classroom suite system for digital learning

Indonesia is a country with vast territory and large number population. The huge size of Indonesia raises variety issues, one of which is the uneven quality of education in various regions. As the technology and information develop, comes up a concept about integration, namely Classroom Suite (CRS). Aims of CRS system is to improve the quality of education in school. CRS system accomodates learning materials in a dedicated place in school and can be accessed from every classroom. The educator can be assisted in teaching process because the materials is readily available. In addition, a school is lack of teacher for a lesson, the other teacher can subtitute to teach the subject because the materials of that lesson already available in CRS system. The main target of CRS system development is to create cheap and easy to use system. To reduce production cost, a board is used as data proccessing unit, namely CRS Box. Moreover, to ease the use of system, a remote application as user interface and application to add new files are developed.

Design of 12-Bit, 40 MS/s Pipeline ADC for application in WiMAX transceiver

12-bit, 40 MS/s Pipeline Analog to Digital Converter is designed for application in WiMAX system. Eleven stages pipeline architecture, consist of ten stages 1.5-bit sub ADC and one stage 2-bit flash ADC. The Project was built until simulation level in SIMetrix software, using AMS BiCMOS 0.35um SiGe transistors model. The simulation showed the ADC has 28dB SFDR.

Safety System Design Simulation for Transcutaneous Electrical Nerve Stimulator using Electrode Contact Test

TENS Transcutaneous Electrical Nerve Stimulator is a therapeutic device used to deliver electric current through ones skin. As the device is used on the human body, safety concern becomes a matter that needs special attention. One option for electrical safety is testing whether the electrode has attached properly to the skin. The test is done in the interval of the simulator pulse. This option is used to protect users from electrical shock that can be caused from this device. Using 74HC4066 as the analog switch, this design can support the TENS specification.