M&MA

Content Management System   Content Management System

Applications of Microwave Engineering The majority of today’s applications of RF and microwave technology are to wireless networking and communications systems, wireless security systems, radar systems, environmental remote sensing, and medical systems.

STAR DELTA connection Diagram and Working principle Descriptions: A Dual starter connects the motor terminals directly to the power supply . Hence, the motor is subjected to the full voltage of the power supply . Consequently , high starting current flows through the motor . This type of starting is suitable for small motors below 5 hp (3.75 kW) . Reduced-voltage starters are employed with motors above 5 hp. Although Dual motor starters are available for motors less than 150kW on 400 V and for motors less than 1 MW on 6.6 kV . Supply reliability and reserve power generation dictates the use of reduced voltage or not to reduce the starting current of an induction motor the voltage across the motor need to be reduced. This can be done by 1. Autotransformer starter , 2. Star-delta starter or 3. Resistor starter . Now-a-days VVVF drive used extensively for speed control serves this purpose also.

Comparison Between Transmission line and Wave guide : Transmission line Wave guide Small cross-section transmission lines (like coaxial cables) can only transmit low power levels due to the relatively high fields concentrated at specific locations within the device Metal waveguides can transmit high power levels. The fields of the propagating wave are spread more uniformly over a larger cross-sectional area than the small cross-section transmission line. Large cross-section transmission lines can transmit high power levels. Large cross-section (low frequency) waveguides are impractical due to large size and high cost .

  Design and Implement of QPSK Modem Based on FPGA. Abstract   : This paper presents a method to designs QPSK modulator and demodulator of a spread spectrum system which use field programmable device.  The method uses the tool of Quartus Ⅱ of American Altera Co. The whole system is divided into several small models based on top-down design method, and using VHDL hardware description language to design each model. 

WCDMA, HSPA, HSPA+, LTE          "An information system formed by HAP (High Altitude Platform) will be a new generation-system for the wireless communications and HAPS (HAP Station) communication system combines the advantages of both terrestrial and satellite communication systems and avoids, to different extents, their disadvantages. Third generation (3G) mobile technology which is specified by the third generation partnership project (3 GPP) is definitely one of the candidates. With the success of wireless network, the IEEE 802.16 standard, with its wireless metropolitan area network (MAN) air interface appears to be a strong competitor. We provide initial practical comparison of these two technologies for HAPS Communication". WCDMA HSPA HSPA+ LTE Maximum Uplink Speed 128 Kbps 5.7 Kbps 11 Mbps 50 Mbps Maximum Downlink Speed 14 Mbps 11 Mbps 28 Mbps 100 Mbps Spectrum FDD

Testability VLSI: Boundry scan Boundary scan is a test technique using scan methodology, involving digital services,  digital devices, designed with shift registers (scan flip flops) placed between each device pin and the internal logic.    These shift registers can control and observe signal values present at each input and  output pin and are connected together in serial fashion to form a data register chain,  called boundary scan shift register with shift and update stages.