RF Control Signal Research Articles

Operation of an RF Modulated Thermionic Electron Source at TRIUMF

The electron source in the TRIUMF ARIEL project is a gridded dispenser cathode. The cathode is biased at -300kV, and the grid requires a RF control signal of up to 150V at 650 MHz. The required RF power is approximately 20 W and is provided by an RF amplifier located outside the gun vessel. This RF power is coupled into the gun circuit through a ceramic transmission line. The design of this ceramic transmission line, as well as the impedance transformation circuit which provides both the impedance matching and the dc powers to the gun assembly are described.

Wearable Wireless Sensor System With RF Remote Activation for Gas Monitoring Applications

Nowadays, the safety standards for industrial plants are tougher with respect to employee state monitoring and monitoring of working environmental conditions. Combining wireless sensor with wearable technology is possible to significantly improve safety delivery capability of such systems and add new functionality to them. Since wireless sensors use batteries as the sole energy source, the energy efficiency becomes critical. One of the solutions to reduce the energy consumption of the wireless sensor nodes is to use appropriate control for radio data transmission. In this paper, we have developed a wireless sensor system which can be attached to a uniform and used for working condition monitoring in places which could be prone to gas leakage. The main feature of the system is the possibility to be activated remotely by an RF control signal at a frequency of 866 MHz. It performs various functions of wearable sensor system, such as switching the system from sleep, measurement, and data transmission modes when external RF signal is available and its power is greater than an appropriate level. The experimental data demonstrate that the activation distance is about 2.75 m from an RF-generator that has a power of 30 dBm. The wearable sensor system is able to signalize about employee presence in relation to working facilities and to monitor temperature and combustible gases concentration. It consists of light-weight distributed parts attached to clothes and has low power consumption.

Wavelength-Division-Multiplex Photonic Routers with Collinear Acoustooptic Processing for Optical Label Matching in Spectral and Time Domains

A collinear acoustooptic (AO) switch has a feature of wavelength-selective switching for wavelength-division-multiplexed (WDM) signals. This feature can be used for photonic packet routing in WDM photonic networks. In this study, the application of collinear AO switches to a label recognition processor in a photonic routing system is investigated. An optical label is assumed to be encoded in spectral and time domains. Collinear AO switches are considered for use in label recognition by using multiple wavelength switching with rf control signals at multiple frequencies. By employing a combination of encoding in spectral and time domains, flexibility in routing control, and the number of represented labels can be increased. Numerical examples of label recognition are also presented.

High contact count, sub-miniature, full implantable cochlear prosthesis

A fully implantable cochlear prosthesis includes: (a) an implantable hermetically sealed case (100) wherein electronic circuitry including a battery and an implantable microphone (1), are housed, (b) an active electrode array (29) that provides a programmable number of active electrode contacts through which stimulation current may be selectively delivered to surrounding tissue, preferably through the use of appropriate stimulation groups, and (c) a connector (9) that allows the active electrode array to be detachably connected with the electronic circuitry within the sealed case. The active electrode array provides a large number of both medial contacts and lateral contacts, any one of which may be selected to apply a stimulus pulse through active switching elements included within the array. The hermetically sealed case within which the electronic circuitry, battery, and microphone are housed may be replaced, when needed, through minimally invasive surgery. Further, the electronic circuitry housed within the hermetically sealed case may be programmed, as needed, using acoustic signals from an acoustic remote control (106) and/or RF control signals from an external programmer (104).

Label Recognition with Wavelength-Selective Collinear Acoustooptic Switches for Photonic Label Routers

Collinear acoustooptic (AO) switches have a feature of wavelength-selective switching for wavelength-division-multiplex (WDM) signals. This feature can be used for photonic packet routing in a WDM photonic network. In this paper, application of the collinear AO switches to a label recognition processor in a photonic routing system is investigated. The optical label uses optical codes which are encoded in the spectral domain. The collinear AO switch is considered to be useful for label recognition by using multiple wavelength switching with multiple frequency rf control signals. The switched and unswitched optical signals are processed with a balanced photodetector. A numerical example for the code recognition is presented.

A 40-Kilovolt, 125-Ampere Hard Tube Modulator for Accelerator Service

A hard tube modulator designed to generate a 40-kilovolt pulse at 125 amperes for 2 milliseconds at 6% duty factor has been constructed. The rise and fall times will be controlled and the flat top regulated to program requirements. The Machlett NL-LPT 14 was used for the switch tube in this application utilizing magnetic focusing with a coarse grid structure and multiple cathode beams to achieve low grid drive with high plate efficiencies. Low grid drive allows simplification of the drive to one tube driven directly from the rectified rf control signal. The rf control signal at 4.8 Mc is coupled across the high voltage interface through a ferrite core transformer.