transmitter RF conversion efficiency

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Low Power QPSK RF Transmitter for
      405-406 MHZ MEDS Band

Low Power QPSK RF Transmitter for 405-406 MHZ MEDS Band

II. PROPOSED QPSK TRANSMITTER ARCHITECTURE Most of realized transmitters targeting MedRadio bands use either amplitude shift-keying (ASK) or frequency shift-keying (FSK) modulations for simpler realization and lower power consumption [7-9]. However, ASK modulation has a poor immunity to noise [10], while FSK and phase shift keying (PSK) are more robust modulation schemes. PSK modulation, when compared to FSK modulation, offers the advantage of lower bit error rate (BER) at the same Eb/N0 [11]. Furthermore, multiple phase shift- keying (M-PSK) offers better bandwidth efficiency than multiple frequency shift- keying. However, the conventional realization of PSK and quadrature PSK (QPSK) modulation mandates the use of two digital to analog converters (DAC) and quadrature up- conversion mixers while using a frequency synthesizer, mostly a phase locked loop, to achieve frequency tuning and channel selection. This system complexity constructs the main obstacle that makes low power transmitters avoids the adoption of PSK and QPSK modulations. Liu et al. illustrated the phase-MUX- based transmitter shown in Fig.1 (a) [12]. In this architecture, Heba A. Shawkey, Ghada H. Ibrahim, Mostafa A. Elmala and Dalia A. El-Dib
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Optoelectronic mixing in heterojunction bipolar transistors

Optoelectronic mixing in heterojunction bipolar transistors

It was mentioned in Section l-3b that the HBT, configured as an up-converting optoelectronic mixer, can be applicable in micro wave/millimetre-wave fibre-radio systems. Suematsu et al. [73,74] have used a GaAs/AlGaAs HBT as an optoelectronic up-converter in delivering millimetre-wave signals over fibre. The HBT studied was not specially designed as a phototransistor but as an MMIC component. When light o f 0.83 /im wavelength was incident normally on the HBT, the photons were absorbed in the base and the collector through the gaps among the emitter, base, and collector electrodes. The photodiode formed by the base-collector junction o f the HBT had an external quantum efficiency o f 30 % to 40 %. Three different fibre optic link configurations were considered in their papers. In link 1 an external modulator was used to intensity modulate a laser beam with an RF input signal at millimetre-wave frequencies at the transmitter and an HBT or a PIN photodiode was employed to detect and regenerate the RF signal at the receiver. In link 2 the external modulator intensity modulated the laser beam merely with the low-frequency IF input signal and the HBT, whose base was driven by the LO source at millimetre-wave frequencies, was used to up-convert the IF modulated optical input signal to an RF output signal at millimetre-wave frequencies. In link 3 the laser beam was again intensity modulated by the external modulator at the same input IF, but the HBT was simply used as a direct photodetector which was then followed by a double balanced diode mixer to perform the up-conversion. It was observed that the S/N for link 2 was 10 dB and 21 dB higher than that for link 1 when the HBT and the p-i-n photodiode
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New formula for conversion efficiency of RF EH and its wireless applications

New formula for conversion efficiency of RF EH and its wireless applications

On the other hand, many researchers have studied the use of energy harvesting in wireless systems. For example, in [17], an energy-constrained wireless link was studied, where the receiver relies on harvesting the energy from the transmitter, by maximizing the throughput. In [18], an energy harvesting relaying system was studied. Two energy harvesting methods, time-switching (TS) and power-splitting (PS), were proposed. In all these works and most existing works, it was assumed that the conversion efficiency of the energy harvester is a fixed value that does not depend on the input power. However, this is not the case in reality. Thus, it is of great interest to study the realistic performances of the wireless systems by treating the conversion efficiency of the energy harvester as a function of the input power, as in practice.
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Direct Conversion 700 MHz RF Transmitter

Direct Conversion 700 MHz RF Transmitter

The electrical currents oscillating at radio frequencies have particular properties that differ from direct current or alternating current. Energy in RF current can radiate from a conductor into space as electromagnetic waves or radio waves. This is the foundation of radio technology. Instead of penetrating deeply into electrical conductors, RF current actually flows along their surfaces known as skin effect. As a result, whilst the human body comes in contact with high power RF currents it caused burns called RF burns. The current can simply ionize air, creating a conductive path through it. It also flows through paths that contain insulating material, like the dielectric insulator of a capacitor. When circuit are conducted by an ordinary electric cable, RF current has a tendency to reflect from discontinuities in the cable such as connectors and travel back down the cable toward the source and causing state named standing waves, so RF current have to be carried by particular types of cable called transmission line [6].
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WAR Field Spying Robot Dissertation

WAR Field Spying Robot Dissertation

receives parallel data input from the microcontroller through the push buttons and transmits this parallel data in serial format through the RF module. On pressing the respective push button, Microcontroller is programmed to send relevant signals to the Encoder in parallel form. The encoder converts these parallel signals to serial form to be transmitted by the RF module. This serial data is modulated with a carrier signal using a RF transmitter and is transmitter. For example if we press the left button, the microcontroller sends the command to the receiver unit through the encoder and the RF module using a wireless CCD camera, which are commonly available in the market. This camera works on 12 volts DC supply. The camera has a receiver, which is placed in the remote station. Its output are in the form of audio and video signals. These signals a re directly sent to a television or a computer through a tuner card. This CCD camera is placed on the robot. The camera captures the audio and video signals and sends those signals to the remote station and with the help of the camera receiver which is connected to the television or a computer through we will be able to see the captured signals. This is a mini wireless monitoring video camera and wireless receiver set for home and small business surveillance, security and is used by us for demonstration purpose
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Design and stability analysis techniques for switching mode nonlinear circuits : power amplifiers and oscillators

Design and stability analysis techniques for switching mode nonlinear circuits : power amplifiers and oscillators

In the case of communication systems with complex modulation schemes such as CDMA, the output power varies dynamically following the modulated input signal. Then, peak envelope power (PEP) is defined by instantaneous output power when the RF output signal reaches its maximum swing. On the other hand, average power is calculated as the time average of the instantaneous output power. The ratio between them, called peak-to-average power ratio, is an important parameter in envelope analysis of linear power amplifiers. However, in switching-mode amplifiers, output power commonly refers to the peak envelope power because the input drive, in most applications, is fixed to make the amplifiers operate in PEP condition. Sometimes, the output power is specified and measured under two different conditions: continuous wave (CW) and pulsed operating conditions, depending on applications. For example, most radar applications or some ISM applications including plasma generation need pulsed operation rather than CW. Output power level along with efficiency determines the amount of power that has to be extracted out of the operating amplifiers by heatsink. Pulsed operation obviously puts less stringent requirements on the heatsink. If duty cycle and efficiency in pulsed operation are D and η, respectively, then the dissipated power that should be extracted by heatsink is
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Charging Station for Electric Vehicles using RF Module

Charging Station for Electric Vehicles using RF Module

promoted the development of green car technology such as electric vehicles which are cost effective too. The number of Electric Vehicles (EVs) on the roads are increasing so charging infrastructure is gaining an important role. There are several issues on the EV charging system and some of them are option for improving the operation and efficiency, understanding of the charging behaviours of existing EV users. Thus, in this paper, we have introduced RFID (radio frequency identification) technology which allows automatic identification of users. This technology uses electromagnetic waves to transmit and receive information of the users.
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Development of RF Remote Control Based Phase Selector System

Development of RF Remote Control Based Phase Selector System

The circuit operation of this system shown in figure 1.6 above is basically a RF remote control based switching system. The system switches from one phase to another when the button in the remote control transmitter is tapped once. In other words, when the transmitter button is pressed, 315MHz signal is transmitted to the receiver which can only decode such frequency signal. In this case, the RF receiver coupled into the main phase selector system act as a transducer. This converts the radiated wave signal into an electrical signal for circuit operation. However, the base of transistor is triggered each time there is signal from the receiver output (T). But, since its collector signal is used as input signal to pin 2 of the NE555 IC, a clock signal is generated across the output at every trigger in the input. This clock signal is basically a square wave signal. At this point, a decade counter start counting each time this clock signal comes in through pin 14. Interestingly, the output signal generated from the decade counter, as a result of the proceeding units is used to switch each phases connected through transistor, relay and contactor. The system also displays it switching state through the present of power indicators. There are; Red ( ), Yellow ( ) and blue ( ) which display the outputs as well as green ( ) for shutdown state. Also the Red ( ), Yellow ( ) and Blue ( ) serve as input indicators.
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SMART TRACKING OF MOBILE PHONE USAGE WITH THE HELP OF JAMMER UNIT

SMART TRACKING OF MOBILE PHONE USAGE WITH THE HELP OF JAMMER UNIT

In this UNIT we will be having a Transmitter and Encoder, Receiver Section and Ignition Unit the Decoder Section. Alerts about the call are being stopped by the jammer unit during the car driving which helps in reducing the accidents and interruption during busy important meetings. As soon as the phone call is received by the base station of the mobile phone, the Ignition Unit is actually switched ON and the signal is transmitted by the RF Transmitter. RF Receiver unit receives the Transmitted signal .The Encoder and Decoder are used to encode and decode the received signals. Thus the Unit of Mobile Section gets alerted and the Jammer initiates its functions by stopping the call alerts by locking the speaker or mic and the keypad of the mobile phone.
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90nm CMOS Direct-Conversion Transmitter Design For WCDMA

90nm CMOS Direct-Conversion Transmitter Design For WCDMA

To better view the specification of EVM for a direct-conversion WCDMA transmitter, a transmitter budget for the EVM and SNR performance is shown in Table 2.1. The budget accounts for a transmitter SNR of 22.1dB or an EVM of 7.9%, which provides ample margin for degradation due to the other EVM degradation sources such as power amplifier distortion and baseband I/Q gain and phase imbalance. Noted that 30dBc is accounted for phase noise. It can be seen from Table 2.1, for a direct-conversion WCDMA transmitter, EVM is mainly dominated by the carrier leakage, image rejection, phase noise, etc., while the in-band distortion and random noise only contributes a minor effect. As long as ACLR requirements are fulfilled, the nonlinearity distortion is only a minor contributor to overall degradation of EVM. It should be noted that this does not imply that meeting the EVM requirements for a transmitter design is trivial. In fact, to achieve good carrier and image suppression, phase noise, etc., careful design and layout is a must, and calibration algorism might be needed.
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R&S DVMS Digital TV Monitoring System Family Ensuring high quality of digital TV network operation

R&S DVMS Digital TV Monitoring System Family Ensuring high quality of digital TV network operation

The R&S®DVMS1 (1 HU, ½ rack width) makes it possible to simultaneously monitor an RF signal and an ASI signal or as an alternative up to four IP flows. The R&S®DVMS4 (1 HU) allows simultaneous monitoring of up to four RF/IP/ ASI signals. Interface modules for DVB-T/DVB-T2, DVB-S/ DVB-S2 as well as for IP (optical/electrical) are available. All relevant errors at the RF, IP, TS and T2-MI level are rec- ognized and reported immediately. Thumbnail display and electronic program guide (EPG) simplify visual monitoring of the transmitted contents. Remote access is supported via an integrated web server allowing independent, simul- taneous access from different locations. SNMP and SNMP traps are supported for integration into central network management systems.
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Exploration of Electromagnetic Interference (EMI) on Shipboard Equipment

Exploration of Electromagnetic Interference (EMI) on Shipboard Equipment

In conclusion, EMI has become one of the most significant factors in radar system for it to be operated in its maximum reliability and efficiency. EMI must be able to be predicted and then is suppressed by analyzing its sources, performing the method for reducing the EMI issue and testing for reaching the EMC. This project has been using only one type of radar model which is monostatic radar with only a static target and with decent usage on EMI that is injected into the radar model. Since this is simulated-based project, testing on a real vessel is highly recommended in obtaining real-time results which can help for commercialization purpose.
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Towards a 15.5W Si-LDMOS Energy Efficient Balanced RF Power Amplifier for 5G-LTE Multi-carrier Applications

Towards a 15.5W Si-LDMOS Energy Efficient Balanced RF Power Amplifier for 5G-LTE Multi-carrier Applications

While verifying the impedances in schematic and layout, the Gerber files are created from the layout and the circuit is milled on the RT/duroid 5880 board. During the RF operation, heat generation of the transistor would be one of the biggest problems causing performance degradation. Therefore, the transistor has to be mounted right on a heat sink in order to diffuse generated heat. In this project, a large piece of aluminium plate will be used as a heat sink and the skeleton to support the PA. The transistor is mounted on the aluminium plate with thermal paste glued in between in order to maximize heat transfer. The PA consists of two parts, the input board and the output board. SMA connectors are inserted at the input and output terminals. Banana plugs must be used for power connection as required by the competition rules. Vias are created by putting wire through drilled holes or inserting long copper tape through cut slits as connection bridges between the top and bottom ground planes. Vias should cover as much area as possible on the PA in order to provide the same reference level between the top and bottom ground planes. Components are then soldered on the board. 300pF capacitors are used as coupling capacitors at the input and output board. 1pF/1000pF/33pF capacitors are used as a decoupling capacitor in the gate bias. 1pF/1000pF/33pF/ capacitors are put in parallel and used as decoupling capacitors in drain bias.
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Rescue of Psycological Infirmity People using Wirless Network

Rescue of Psycological Infirmity People using Wirless Network

can be used with diverse technologies (Bluetooth, Ultrasound). Apart from adding functionalities to the existing network or the presence of detection, the range estimation is the base to create a system of indoor positioning. The personal area network are network for interconnection of devices near a person that habitually have smaller reaches of 10 meters. In this article, used to provide the protection for psychological infirmity people. We can create intra network between psychological infirmity people with RF communication. Main objective is to reduce the missing rate of psychological infirmity people with the coverage area of 400 meters that is probably about 433MHZ
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Automatic Intravenous Fluid Level Indication System for Hospitals

Automatic Intravenous Fluid Level Indication System for Hospitals

The intravenous therapy is not only used to correct electrolyte imbalances but it can also be used to deliver medicines. Patients those who cannot consume enough nutrients or who cannot eat at all due to an illness, surgery or accident, can be feeded with enough nutrition through their vein using IV therapy. These sterile solutions (sodium and dextrose) containing necessary nutrients to support the human life which is injected into the patient’s body through a tube attached to the needle. Due to lack of caring, many problems will arise such as blood loss, backflow of blood through an IV tube. To overcome this situation an effective idea is proposed to develop an effective health monitoring system which alerts the doctor or nurse when the fluid level of saline bottle is beyond the threshold limit. It comprises of IR sensor, RF transmitter, Receiver, buzzer, etc. Basically IR transmitter transmits an IR ray which is received by the IR receiver and the measured output is in terms of voltage. Fig.2 shows the block diagram of Automatic drips level Indicating system. Initially IR sensors (IR Transmitter – IR Receiver ) are placed at the bottom on either sides of saline bottle. The IR transmitter continuously transmits the rays through the saline liquid and the IR receiver starts to receive it and the corresponding output voltage is measured as 4.5V. When the process is going on, slowly the saline liquid enters into the patient’s body through their vein. This is done with the help of intravenous (IV) set. Hence the level of nutritious liquid in the saline bottle is getting decreased gradually. When the medication liquid in the drips bottle goes beyond IR sensor covering area, the IR receiver receives more rays than in previous condition whose output voltage is measured as 5V.
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Design Of Rectifying Circuit With Improved RF-DC Conversion For RF Wireless Power Transfer

Design Of Rectifying Circuit With Improved RF-DC Conversion For RF Wireless Power Transfer

Finite electrical battery life provides researchers and company's motivation to generate a new idea and technologies produce wireless mobile devices to have an infinite or enhanced period of time [2]. Battery in wireless mobile devices is the main power source of power on the device. Batteries in wireless mobile devices increase the size of the device. Besides, the battery is not environmentally friendly and cause pollution the environment [4]. RF energy harvesting is able to support various applications. Besides, RF energy harvesting can increase the lifetime of the devices. RF energy harvesting is able to reduce or eliminate the usage of the battery in the devices [1]. The challenge of this technology is the efficiency of the RF energy harvesting system to convert the RF energy into DC energy. Due to the rectifying circuit mostly will affect the performances of the energy harvesting system. Thus, the design of the rectifying circuit has to provide a great efficient in converting RF energy to DC. The ON/OFF characteristic and the threshold voltage of the diode in the rectifying circuit will affect the RF-DC conversion performance of the rectifying circuit [5]. In recent design such as [1] use CMOS to design the rectifier circuit. This type of method increases the cost to produce the rectifying circuit and cannot produce high DC voltage. Thus, by using a Schottky diode that provides low forward voltage and high switching speed and increase the stages of the rectifying circuit can increase the efficiency of RF-DC conversion for the rectifying circuit.
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ViaLite Wideband RF Fibre Optic Link

ViaLite Wideband RF Fibre Optic Link

The digital channel is independent of RF transmission and is capable of transmitting up to 20kbps digital data simultaneously. There are two built-in digital interfaces, one (pin 2 and 3) for RS422/485 signals and the other (pin 4) for RS232/TTL signals. Only one interface can be used at a time. If TTL signal is chosen, it must meet V INH >=2.4V. See connection details below.

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EUROPEAN ETS TELECOMMUNICATION November 1990 STANDARD

EUROPEAN ETS TELECOMMUNICATION November 1990 STANDARD

A device to key an associated transmitter in advance of the first bit to the transmitted shall be available. This device may be combined with the device to activate and de-activate an associated receiver (subclause 7.4). The time between the activation of the transmitter and the start of the first bit shall be internally adjustable either continuously or in steps of not more than 1.5 msec. from 0 msec. up to a minimum of 100 msec.

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Design and Implementation of Wireless Live Wire Fault Detector and Protection in Remote Areas

Design and Implementation of Wireless Live Wire Fault Detector and Protection in Remote Areas

In remote and hilly areas, the faults in the live wires are difficult to analyse. The faults in the wire may be due to breakage in the wire, breakage due to heavy rain, snowfall and land slide, human and animal contact or lightening strike. In an electric power system fault is any abnormal electric current. RF Transreceivers have been proposed for detection of faults in the live wire. This technique can detect the faults in the wires, unapproachable by humans. RF Transmitter units are fixed along the length of wire at regular intervals, the RF receiver unit is placed at approachable area. Signal communication occurs between the transmitter and receiver unit. The transmitter units designed consists of a RF transmitter module which transmits the signal as long as it receives the power. The microcontroller receives the signal through the relay. The voltage fluctuation circuit constantly monitors the voltage level in the wire,and auto cuts-off power in case of voltage fluctuations. The transmitter unit which doesnot transmit the signal, indicates the area of fault in the wire. The receiver unit comprising of the RF receiver module,receives all the signals from the transmitter units accordingly. If all the transmitters’ signals are received,this indicates that there is no fault in the wire. The transmitter unit from which the signal is not received,indicates the portion or area of the fault in the wire. The relay circuit in the transmitter unit auto cuts-off power in case of the fault detected. The decoder circuit connected to the RF receiver passes the signal to the microcontroller which is displayed. These messages can be transferred to any desired location through the GSM module present on the receiver unit. Hence the fault location can be detected and the circuit is protected in case of fault and voltage fluctuations in the wire.
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Ramp Test Set NAV-402AP-3. Operation Manual Issue-3

Ramp Test Set NAV-402AP-3. Operation Manual Issue-3

O A six-digit counter which indicates the RF of the signal generator on any band, the frequency of a COM Transmitter under test, any external signal input from 1 MHz to at least 300 MHz, or the VOR Bearing selected by the Bearing Select Switches. O A built-in RF power meter measures COM

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