201 research outputs found
The Frequency Distribution of Quantization Error in Digitizers for Coherent Sampling
In this paper the frequency distribution of quantization error in coherent sampling of digitizers will be investigated. As the distribution of the quantization error affects the values of THD and SNR, it is relevant for a correct interpretation of THD and SNR of sine waves in coherent sampling. The distribution of the quantization error will be analyzed as a function of N, total number of samples and M, number of cycles in the sample set and it will be proved that for certain cases, the quantization error falls on odd harmonics only of the frequency of the sampled sine wave
Development of a PJVS System for Quantum-Based Sampled Power Measurements
The paper deals with recent progresses at INRiM towards the development and characterization of a programmable Josephson voltage standard (PJVS) operating in a small liquid helium dewar as well as with its integration for the realization of a practical quantum sampling electrical power standard. The
PJVS is based on a 1V superconductor-normal metal-superconductor (SNS) binary-divided array of 8192 Josephson junctions. To ensure proper operating conditions of the PJVS chip, a custom short cryoprobe was designed, built and successfully tested. The overall system is being developed in the framework of EMPIR project 19RPT01-QuantumPower. The goal is to establish a new quantum power standard (QPS) based on a single Josephson voltage standard for sampled power measurements and to gain confidence
in running PJVS for precise calibration of digital sampling multimeters and arbitrary waveform digitizers used in the ac-voltage and power metrology community
Multitones’ Performance for Ultra Wideband Software Defined Radar
This chapter proposes and tests an approach for an unbiased study of radar waveforms’ performances. Through an empirical performance analysis, the performances of Chirp and Multitones are compared with both simulations and measurements. An ultra wideband software defined radar prototype was designed and the prototype has performances comparable to the state of the art in software defined radar. The study looks at peak-to-mean-envelope power ratio, spectrum efficiency, and pulse compression as independent waveform criteria. The experimental results are consistent with the simulations. The study shows that a minimum of 10 bits resolution for the AD/DA converters is required to obtain near-optimum performances
PuMaII: A wide band pulsar machine for the WSRT
The Pulsar Machine II (PuMa II) is the new flexible pulsar processing backend
system at the Westerbork Synthesis Radio Telescope (WSRT), specifically
designed to take advantage of the upgraded WSRT. The instrument is based on a
computer cluster running the Linux operating system, with minimal custom
hardware. A maximum of 160 MHz analogue bandwidth sampled as 8X20 MHz subbands
with 8-bit resolution can be recorded on disks attached to separate computer
nodes. Processing of the data is done in the additional 32-nodes allowing near
real time coherent dedispersion for most pulsars observed at the WSRT. This has
doubled the bandwidth for pulsar observations in general, and has enabled the
use of coherent dedispersion over a bandwidth eight times larger than was
previously possible at the WSRT. PuMa II is one of the widest bandwidth
coherent dedispersion machines currently in use and has a maximum time
resolution of 50ns. The system is now routinely used for high precision pulsar
timing studies, polarization studies, single pulse work and a variety of other
observational work.Comment: 29 pages, 8 figures. To appear in February issue of the PAS
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