5,263 research outputs found
A Coupled Sawtooth Oscillator combining Low Jitter and High Control Linearity
A new type of current controlled oscillator (CCO) is presented that combines excelllent control linearity with low timing jitter. The problem of overshoot in traditional relaxation oscillators is solved by using an alternative for the Schmitt-trigger. Circuits realised in a 0.8µm CMOS process show a HD2 < -65dB and HD3 < -85 dB (¿f=500 kHz). The measured phase noise is smaller than -100dBc/Hz at 10kHz carrier offset frequency at FOSC=1.5 MHz for a supply current of 360µA
The re-emission spectrum of digital hardware subjected to EMI
The emission spectrum of digital hardware under the influence of external electromagnetic interference is shown to contain information about the interaction of the incident energy with the digital circuits in the system. The generation mechanism of the re-emission spectrum is reviewed, describing how nonlinear effects may be a precursor to the failure of the equipment under test. Measurements on a simple circuit are used to demonstrate how the characteristics of the re-emission spectrum may be correlated with changes to the digital waveform within the circuit. The technique is also applied to a piece of complex digital hardware where Similar, though more subtle, effects can be measured. It is shown that the re-emission spectrum can be used to detect the interaction of the interference with the digital devices at a level well below that which is able to cause static failures in the circuits. The utility of the technique as a diagnostic tool for immunity testing of digital hardware, by identifying which subsystems are being affected by external interference, is also demonstrated
Geometrical jitter and bolometric regime in photon detection by straight superconducting nanowire
We present a direct observation of the geometrical jitter in single photon
detection by a straight superconducting nanowire. Differential measurement
technique was applied to the 180-{\mu}m long nanowire similar to those commonly
used in the technology of superconducting nanowire single photon detectors
(SNSPD). A non-gaussian geometrical jitter appears as a wide almost uniform
probability distribution (histogram) of the delay time (latency) of the
nanowire response to detected photon. White electrical noise of the readout
electronics causes broadened, Gaussian shaped edges of the histogram.
Subtracting noise contribution, we found for the geometrical jitter a standard
deviation of 8.5 ps and the full width at half maximum (FWHM) of the
distribution of 29 ps. FWHM corresponds to the propagation speed of the
electrical signal along the nanowire of m/s or 0.02 of the
speed of light. Alternatively the propagation speed was estimated from the
central frequency of the measured first order self-resonance of the nanowire.
Both values agree well with each other and with previously reported values. As
the intensity of the incident photon flux increases, the wide probability
distribution collapses into a much narrower Gaussian distribution with a
standard deviation dominated by the noise of electronics. We associate the
collapse of the histogram with the transition from the discrete, single photon
detection to the uniform bolometric regim
Phase and amplitude pre-emphasis techniques for low-power serial links
A novel approach to equalization of high-speed serial links combines both amplitude pre-emphasis to correct for intersymbol interference and phase pre-emphasis to compensate for deterministic jitter, in particular, data-dependent jitter. Phase pre-emphasis augments the performance of low power transmitters in bandwidth-limited channels. The transmitter circuit is implemented in a 90-nm bulk CMOS process and reduces power consumption by pushing CMOS static logic to the output stage, a 4:1 output multiplexer. The received signal jitter over a cable is reduced from 16.15 ps to 10.29 ps with only phase pre-emphasis at the transmitter. The jitter is reduced by 3.6 ps over an FR-4 backplane interconnect. A transmitter without phase pre-emphasis consumes 18 mW of power at 6Gb/s and 600mVpp output swing, a power budget of 3mW/Gb/s, while a transmitter with phase pre-emphasis consumes 24mW, a budget of 4 mW/Gb/s
Low Noise and High Photodetection Probability SPAD in 180 nm Standard CMOS Technology
A square shaped, low noise and high photo-response single photon avalanche diode suitable for circuit integration, implemented in a standard CMOS 180 nm high voltage technology, is presented. In this work, a p+ to shallow n-well junction was engineered with a very smooth electric field profile guard ring to attain a photo detection probability peak higher than 50% with a median dark count rate lower than 2 Hz/ÎĽm2 when operated at an excess bias of 4 V. The reported timing jitter full width at half maximum is below 300 ps for 640 nm laser pulses
4-Dimensional Tracking with Ultra-Fast Silicon Detectors
The evolution of particle detectors has always pushed the technological limit
in order to provide enabling technologies to researchers in all fields of
science. One archetypal example is the evolution of silicon detectors, from a
system with a few channels 30 years ago, to the tens of millions of independent
pixels currently used to track charged particles in all major particle physics
experiments. Nowadays, silicon detectors are ubiquitous not only in research
laboratories but in almost every high-tech apparatus, from portable phones to
hospitals. In this contribution, we present a new direction in the evolution of
silicon detectors for charge particle tracking, namely the inclusion of very
accurate timing information. This enhancement of the present silicon detector
paradigm is enabled by the inclusion of controlled low gain in the detector
response, therefore increasing the detector output signal sufficiently to make
timing measurement possible. After providing a short overview of the advantage
of this new technology, we present the necessary conditions that need to be met
for both sensor and readout electronics in order to achieve 4-dimensional
tracking. In the last section we present the experimental results,
demonstrating the validity of our research path.Comment: 72 pages, 3 tables, 55 figure
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