Cold-Source Noise Measurement of a Differential Input Single-Ended Output Low-Noise Amplifier Connected to a Low-Frequency Radio Astronomy Antenna

Sutinjo, Adrian; Ung, D.; Juswardy, Budi

doi:10.1109/tap.2018.2854285

Cited by 14 publications

(17 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We then apply the various T rcv formulations presented in Sect. II using the measured noise parameters and S-parameters of the LNA previously measured in [9]. note that all three different methods presented converges for various pointing direction and array configurations (uniform and pseudo-random configuration) which indicated agreement in current literature of computing receiver noise temperature.…”

Section: Resultssupporting

confidence: 70%

“…Following noise extraction of a low noise amplifier (LNA) as utilized by the Murchision Widefield Array (MWA) [7], [8] seen in [9], we now aim to compute the receiver noise temperature of MWA, which is a uniform array, and Engineering Development Array (EDA) [3], which is a pseudo-random array using existing formulations which accounts for mutual coupling.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Biased interpretation in perfectionistic concerns: an experimental investigation

Howell

McEvoy

Grafton

et al. 2019

Anxiety, Stress, & Coping

View full text Add to dashboard Cite

We present the computation of receiver noise temperature which includes the effects of mutual coupling of two different radio telescopes deployed in the Murchison Radioastronomy Observatory, namely the Murchison Widefield Array and the prototype Engineering Development Array. We used three different formulations that only require information of measured noise parameters of the low noise amplifier as used in the radio telescope and simulated S-parameter of the array to perform the calculation. In addition, we show convergence in computed receiver noise temperature for various pointing angles and array configurations (uniform and pseudo-random) that indicate agreement with existing literature.

show abstract

Section: Resultssupporting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Biased interpretation in perfectionistic concerns: an experimental investigation

Howell

McEvoy

Grafton

et al. 2019

Anxiety, Stress, & Coping

View full text Add to dashboard Cite

show abstract

“…The frequency of interest was 154.88 MHz, which corresponded to the channel number 121. To calculate the system temperature, we also used measured S-parameters and noise parameters of the LNA (Sutinjo et al 2018), as well as the Haslam 408 MHz all-sky map (Haslam et al 1982) scaled to 154.88 MHz using a spectral index of −2.55 (Mozdzen et al 2019). The Galactic contribution corresponded to the day and time of the observation.…”

Section: Simulation Predictions For the Mwamentioning

confidence: 99%

Sensitivity of a low-frequency polarimetric radio interferometer

Sutinjo

Sokołowski

Kovaleva

et al. 2021

A&A

Self Cite

View full text Add to dashboard Cite

Context. The sensitivity of a radio interferometer is a key figure of merit (FoM) for a radio telescope. The sensitivity of a single polarized interferometer is typically given as an antenna effective area over a system temperature, Ae/Tsys, assuming an unpolarized source. For a dual-polarized polarimetric interferometer intended to observe sources of unknown polarization, the state of polarization must not be assumed a priori. Furthermore, in contrast to the narrow field of view (FoV) of dish-based interferometers, the sensitivity of a polarimetric low-frequency radio interferometer warrants a careful review because of the very wide FoV of the dual-polarized antennas. A revision of this key FoM is particularly needed in the context of the Low-Frequency Square Kilometre Array (SKA-Low) where the sensitivity requirements are currently stated using Ae/Tsys for a single-polarized antenna system, which produces ambiguity for off-zenith angles. Aims. This paper aims to derive an expression for the sensitivity of a polarimetric radio interferometer that is valid for all-sky observations of arbitrarily polarized sources, with neither a restriction on FoV nor with any a priori assumption regarding the polarization state of the source. We verify the resulting formula with an all-sky observation using the Murchison Widefield Array telescope. Methods. The sensitivity expression was developed from first principles by applying the concept of system equivalent flux density (SEFD) to a polarimetric radio interferometer (not by computing Ae/Tsys). The SEFD was calculated from the standard deviation of the noisy flux density estimate for a target source due to system noise. Results. The SEFD for a polarimetric radio interferometer is generally not 1/√2 of a single-polarized interferometer as is often assumed for narrow FoV. This assumption can lead to significant errors for a dual-polarized dipole based system, which is common in low-frequency radio astronomy: up to ∼15% for a zenith angle with a coverage of 45° and up to ∼45% for 60° coverage. The worst case errors occur in the diagonal planes of the dipole for very wide FoV. This is demonstrated through theory, simulation, and observations. Furthermore, using the resulting formulation, the calculation of the off-zenith sensitivity is straightforward and unambiguous. Conclusions. For wide FoV observations pertinent to a low-frequency radio interferometer such as SKA-Low, the narrow FoV and the single-polarized sensitivity expressions are not correct and should be replaced by the formula derived in this paper.

show abstract

“…From this information, we obtain T sky ≈ 228 K (ν/150 MHz) −2.53 at the location of the CDFS. Following Wayth et al (2015), we set T rec = 50 K except at ν > 200 MHz, where we set T rec = 80 K; laboratory measurements by Sutinjo, Ung, & Juswardy (2018), indicate that T rec ≈ 80 K at ν > 200 MHz. We set B = 0.75 × 7.68 MHz given a 25% reduction in the bandwidth due to flagged edge channels.…”

Section: Estimating the Thermal Noisementioning

confidence: 99%

Source counts and confusion at 72–231 MHz in the MWA GLEAM survey

Franzen

Vernstrom

Jackson

et al. 2019

Publ. Astron. Soc. Aust.

View full text Add to dashboard Cite

The GaLactic and Extragalactic All-sky MWA survey (GLEAM) is a radio continuum survey at 72-231 MHz of the whole sky south of declination +30 • , carried out with the Murchison Widefield Array (MWA). In this paper, we derive source counts from the GLEAM data at 200, 154, 118 and 88 MHz, to a flux density limit of 50, 80, 120 and 290 mJy respectively, correcting for ionospheric smearing, incompleteness and source blending. These counts are more accurate than other counts in the literature at similar frequencies as a result of the large area of sky covered and this survey's sensitivity to extended emission missed by other surveys. At S 154 MHz > 0.5 Jy, there is no evidence of flattening in the average spectral index (α ≈ −0.8 where S ∝ ν α ) towards the lower frequencies. We demonstrate that the SKA Design Study (SKADS) model by Wilman et al. significantly underpredicts the observed 154 MHz GLEAM counts, particularly at the bright end. Using deeper LOFAR counts and the SKADS model, we find that sidelobe confusion dominates the thermal noise and classical confusion at ν 100 MHz due to both the limited CLEANing depth and undeconvolved sources outside the field-of-view. We show that we can approach the theoretical noise limit using a more efficient and automated CLEAN algorithm.

show abstract

Cold-Source Noise Measurement of a Differential Input Single-Ended Output Low-Noise Amplifier Connected to a Low-Frequency Radio Astronomy Antenna

Cited by 14 publications

References 27 publications

Biased interpretation in perfectionistic concerns: an experimental investigation

Biased interpretation in perfectionistic concerns: an experimental investigation

Sensitivity of a low-frequency polarimetric radio interferometer

Source counts and confusion at 72–231 MHz in the MWA GLEAM survey

Contact Info

Product

Resources

About