scholarly journals MWA tied-array processing III: Microsecond time resolution via a polyphase synthesis filter

2020 ◽  
Vol 37 ◽  
Author(s):  
S. J. McSweeney ◽  
S. M. Ord ◽  
D. Kaur ◽  
N. D. R. Bhat ◽  
B. W. Meyers ◽  
...  
Keyword(s):  
Time Resolution ◽  
Array Processing ◽  
High Time ◽  
High Time Resolution ◽  
Potential Error ◽  
Murchison Widefield Array ◽  
Synthesis Filter ◽  
Resolution Data

Abstract A new high time resolution observing mode for the Murchison Widefield Array (MWA) is described, enabling full polarimetric observations with up to $30.72\,$ MHz of bandwidth and a time resolution of ${\sim}$ $0.8\,\upmu$ s. This mode makes use of a polyphase synthesis filter to ‘undo’ the polyphase analysis filter stage of the standard MWA’s Voltage Capture System observing mode. Sources of potential error in the reconstruction of the high time resolution data are identified and quantified, with the $S/N$ loss induced by the back-to-back system not exceeding $-0.65\,$ dB for typical noise-dominated samples. The system is further verified by observing three pulsars with known structure on microsecond timescales.

scholarly journals A New Technique for Precise Stellar Photometry: Application to Small-Scale Activity of EV Lacertae

1995 ◽  
Vol 151 ◽  
pp. 133-134 ◽  
Author(s):  
B.E. Zhilyaev
Keyword(s):  
Time Resolution ◽  
High Time ◽  
Small Scale ◽  
High Time Resolution ◽  
Stellar Photometry ◽  
A New Technique ◽  
Ev Lac ◽  
Counting Statistics ◽  
Simple Integration ◽  
Resolution Data

AbstractA new prefiltering technique (PFT) for precise stellar photometry is described. It has been proved that the prefiltered and added high-time resolution data provide an increase in S/N ratio by factors 1.3 — 1.7 in comparison with simple integration. The PFT allows to detect event amplitudes which are comparable to that caused by counting statistics. Adopting the PFT, our observations reveal small-scale flare events in the subsecond range in EV Lac.

scholarly journals The High Time and Frequency Resolution Capabilities of the Murchison Widefield Array

2015 ◽  
Vol 32 ◽  
Author(s):  
S. E. Tremblay ◽  
S. M. Ord ◽  
N. D. R. Bhat ◽  
S. J. Tingay ◽  
B. Crosse ◽  
...  
Keyword(s):  
Radio Emission ◽  
Time Resolution ◽  
High Time ◽  
Frequency Resolution ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Radio Telescopes ◽  
Initial Design ◽  
Imaging Telescope ◽  
Murchison Widefield Array

AbstractThe science cases for incorporating high time resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and frequency resolution voltage data. However, the flexibility of the MWA’s software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 μs and 10 kHz resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.

scholarly journals Survey of Ionospheric Pc3-5 ULF Wave Signatures in SuperDARN High Time Resolution Data

2018 ◽  
Vol 123 (5) ◽  
pp. 4215-4231 ◽  
Author(s):  
X. Shi ◽  
J. M. Ruohoniemi ◽  
J. B. H. Baker ◽  
D. Lin ◽  
E. C. Bland ◽  
...  
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Ulf Wave ◽  
Resolution Data

scholarly journals Verifying the low frequency pulsar polarimetry of the MWA

2017 ◽  
Vol 13 (S337) ◽  
pp. 416-417
Author(s):  
Steven E. Tremblay ◽  
Mengyao Xue ◽  
N. D. Ramesh Bhat ◽  
Caterina Tiburzi
Keyword(s):  
Time Resolution ◽  
Low Frequency ◽  
High Time ◽  
High Time Resolution ◽  
Geometric Information ◽  
Pulsar Emission ◽  
Rich History ◽  
Linear Polarisation ◽  
Resolution Data

AbstractStudying the polarised properties of pulsars has a rich history giving unique geometric information about pulsars as well as testing the theories of pulsar emission physics. Performing such studies with the MWA has the attraction that the percentage of linear polarisation of many pulsars increases as the observing frequency decreases. Here we discuss the strategies being employed to verify the polarimetric response of the MWA’s high time resolution data.

Vys: A Protocol for Commensal Fast Transient Searches and Data Processing at the Very Large Array

2018 ◽  
Vol 07 (02n03) ◽  
pp. 1850005 ◽  
Author(s):  
Martin Pokorny ◽  
Casey J. Law ◽  
Geoffrey C. Bower ◽  
Sarah Burke-Spolaor ◽  
Bryan J. Butler ◽  
...  
Keyword(s):  
Time Resolution ◽  
Data Stream ◽  
Detection System ◽  
High Time ◽  
High Time Resolution ◽  
Large Array ◽  
Very Large Array ◽  
Real Time Analysis ◽  
Fast Transient ◽  
Resolution Data

We describe a new protocol deployed at the National Radio Astronomy Observatory’s Karl G. Jansky Very Large Array (VLA) to support the distribution of data in support of commensal data analysis. The protocol, vys, is designed to provide access to a high time resolution data stream while a primary observation continues with the typical (lower) time resolution data stream. This form of dual time resolution, commensal observing has been implemented to enable the search for millisecond astrophysical transient events by a new, dedicated compute cluster located at the VLA. The fast transient detection system, realfast, performs real-time analysis in situ to detect events of interest and record relatively short duration data “cut-outs” of those events. By selectively recording high time resolution data, provided by vys at rates of up to 1.4[Formula: see text]GB[Formula: see text]s[Formula: see text], realfast will reduce the recorded data volume by an estimated factor of up to 1000. This makes it possible to search for transients commensally in a high data rate stream over the thousands of hours needed to find the rarest events.

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