Pulse Generators

A time-to-digital-converter-based CMOS smart temperature sensor is proposed for high-accuracy portable applications. Conventional smart temperature sensors rely on an analog-to-digital converter, which consumes much chip area and operating power, for digital output code conversion. For the purpose of cost reduction and power saving, the proposed smart temperature sensor first generates a pulse with a width proportional to the measured temperature. Then, a cyclic time-to-digital converter (TDC) is utilized to convert the pulse into the corresponding digital code. The test chips, with extremely small area of 0.175 mm2, were fabricated by the TSMC CMOS 0.35 μm 2P4M process. Due to the excellent linearity of the digital output, the achieved measurement error is merely -0.6°C to +0.8°C without any curvature correction or dynamic offset-cancellation. The effective resolution is better than 0.15°C, and the power consumption is 10 μW.

Using a novel sub-nanosecond pulse current-voltage measurement technique, InGaP/GaAs heterojunction bipolar transistors were shown to survive strong impact ionization and to have a much larger safe operating area than previously measured or predicted. As the result, an empirical model for impact ionization was constructed and added to a commercially available HBT model. The modified model can predict the HBT characteristics across the enlarged safe operating area, including strong avalanche breakdown and flyback. The modified model can be used to simulate not only the ruggedness of high-power amplifiers, but also the performance of ultra-wideband pulse generators.

A multi-wavelength Brillouin erbium fiber laser (BEFL) with a Q-switching characteristic is demonstrated using a piece of non-zero dispersion shifted fiber (NZ-DSF) as a Brillouin gain medium (BGM) in conjunction with relaxation oscillation technique. The performance of the multi-wavelength short pulse generation is investigated for two different BEFL configurations for single and double Brillouin spacing outputs. The Q-switched BEFL generates a pulse train with repetition rates of 10.36 and 20.41 kHz whose corresponding pulse widths are 13.21 and 3.84 μs for the single and double Brillouin spacing outputs, respectively. The self-starting pulses are obtained within a low 1480-nm pump power region at a slightly higher power than the lasing threshold power. This pulse laser based on stimulated Brillouin scattering (SBS) is fairly stable at room temperature. © 2009-2012 IEEE.

http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=6548080

This paper describes the integration in a CMOS 130 nm technology of an ultra wide band (UWB) pulse generator. The implemented generator controls the output pulse shape, and thus the corresponding spectrum. Furthermore, the pulse generator supports both position modulation (2-PPM) and polarity modulation (BPSK) and draws 5 mA from 1.2 V. Spectral and temporal laboratory measurements of the single-chip pulse generator are presented.

We have generated sub-single-cycle pulses of electromagnetic radiation with pulse energies as high as 0.8,tJ and pulse lengths < 500 fs. The 10-dB width of the spectrum is 1.5 THz. The transmitter is a GaAs wafer illuminated at normal incidence by 120-fs, 770-nm pulses from a Ti:sapphire chirped-pulse amplifier system while a pulsed electric field is applied across the surface. The pulse energy of the far-infrared radiation is found to be a quadratic function of bias field and a nonmonotonic function of laser intensity. Picosecond and subpicosecond far-infrared (FIR) electromagnetic pulses have been generated with several optical switching techniques. ' 5 Most interesting for high-power applications is the planar photoconductor, which produces coherent radiation in the directions of optical specular reflection and transmission when illuminated with ultrashort light pulses. 5 Both GaAs and InP wafers have been used for this purpose. Sampling measurements have

The Eros facility at AWE was designed to simulate radiation effects using a large area diode driven by a low impedance Blumlein charged by a Marx generator. Recent interest at AWE to develop low impedance, high current pinched diodes, have lead to a ...

The traditional stimulus signal used in a time-domain reflectometer (TDR) is a voltage step. We propose an alternative technique, whereby an impulse generator is employed in place of the step generator in a TDR. The advantage conferred by “impulse TDR” is that more energy is available at higher frequencies than with conventional step TDR, and so a higher bandwidth and signal-to-noise ratio (SNR) is achieved. The theoretical result is compared with measurement.

In this paper, wireless telemetry using the near-field coupling technique with round-wire coils for an implanted car- diac microstimulator is presented. The proposed system possesses an external powering amplifier and an internal bidirectional mi- crostimulator. The energy of the microstimulator is provided by a rectifier that can efficiently charge a rechargeable device. A fully integrated regulator and a charge pump

The traditional stimulus signal used in a time-domain reflectometer (TDR) is a voltage step. We propose an alternative technique, whereby an impulse generator is employed in place of the step generator in a TDR. The advantage conferred by “impulse TDR” is that more energy is available at higher frequencies than with conventional step TDR, and so a higher bandwidth and signal-to-noise ratio (SNR) is achieved. The theoretical result is compared with measurement.

In this paper, a double-edge triggered level converter flip-flop (DE-LCFFF) is proposed. The flip-flop makes use of the conditional discharging technique which effectively suppress the dynamic power consumption during transition time and the self-precharging technique to automatically precharge its dynamic node after enough time. An explicit double-edge pulse generator is used to further decrease the power consumption in the proposed LCFF. In addition, the use of pass gate transistors and more simplified structure in the main block of DELCFFF leads to a less leakage power consumption. The increase in the speed is achieved by reducing the number of the stack transistors in the discharge path and using less complicated circuit structure. When compared to the previous level converter flip-flops, the proposed LCFF shows considerable reductions in the power consumption, the delay, and the area.

A novel approach for inducing and monitoring oscillations in a molten weld pool is presented. Research efforts have illustrated that the weld pool resonates at natural frequencies that are related to its dimensions and state of penetration. This phenomenon may be used to monitor the weld pool, and particularly its depth of penetration, in a closed-loop feedback control system. The approach used to induce pool oscillations was to excite the weld pool with current pulses synchronized to the natural oscillations of the pool. Implementation of this synchronous weld pool pulsing technique was based on the use of a phase locked loop (PLL) system. The natural weld pool oscillations are used as the reference frequency source and a pulsing circuit is controlled by the PLL oscillator so that the arc current pulses repeatedly impact the pool after a fixed number of reference oscillation periods. An optical sensor detects the pool oscillations which are amplified, filtered, and limited to eliminate amplitude variations from the optical signal. A model of the weld pool is developed which uses a fluid droplet formulation for the relation of weld pool geometry and other physical parameters to the natural frequencies of the weld pool. Comparison of the weld pool's actual resonant frequency with the expected resonant frequency as predicted by weld pool geometry models and measurements of the pool width (or area) allows and assessment of the state of penetration of the weld pool into the workpiece

This paper reports on the design and modelling of an experimental test stand developed to examine the performance of a flowing high-pressure liquid dielectric design verification switch under rep-rate conditions. The test stand is designed to generate 70 ns long, 250-300 kV pulses at 250 J per pulse and 100 pps continuous mode operation. Short-duration bursts at 1000 pps will be used to examine switch recovery characteristics.

A compact four stage Marx with six parallel Marx generators per stage and a common switch housing, developed for various Air Force applications, is described. Unique features of the compact Marx include a single cast epoxy switch housing common to each stage that can use six independent spark gaps or one continuous ring gap packaged in a housing measuring 76