Arcetri Astrophysical Observatory

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logosmallarcetri Arcetri Technical Report 5/2016


SKA Project Series
LFAA Station Beamformer structure

G. Comoretto

INAF Osservatorio Astrofisico di Arcetri

Abstract

The LFAA tile processing modules (TPM) combine the signals from 256 dual-polarization antennas, in the frequency range 50-350 MHz, into a single station beam. Beamforming is done hyerachically, with the TPM first combining the 16 antennas that are processed in the module, and summing this partial sum in a network packet that travels across the 16 TPMs composing a station. This station beamformer performs also a corner turning operation, rearranging the channelized samples from the tile beamformer into sequences of contiguous time samples for a singhle channel at a time.

Pdf version of this report

 

logosmallarcetri Arcetri Technical Report 2/2016


SKA Project Series
SKA - Commands and Setting for CSP

C.Baffa, E.Giani, M.Vela Nuñez

INAF Osservatorio Astrofisico di Arcetri

Abstract

During the normal set-up and programming of the many elements and sub-element of SKA it arises the necessity to program many parameter and to execute different commands. During the development of CSP.LMC prototype we designed a flexible schema to implement such functionality inside the TANGO Control paradigm used in SKA Control and Monitor. We sketch here our implementation proposal and analyse few use cases.

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logosmallarcetri Arcetri Technical Report 4/2016


SKA Project Series
SKA - LMC Standard Files Location

C.Baffa, M.Vela Nuñez

INAF Osservatorio Astrofisico di Arcetri

Abstract

This Memo describes a proposal for a unified location of relevant files for all LMCs development. While this issue may appear a minor one, a standard file structure greatly simplify the interchange of code, and the consequent synergy..

The proposal follows the main guidelines of the Linux Filesystem Hierarchy Standard (FHS).

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logosmallarcetri Arcetri Technical Report 3/2016


SKA Project Series
Quantization noise, linearity and spectral whitening in the LFAA quantizer

G. Comoretto

INAF Osservatorio Astrofisico di Arcetri

Abstract

The LFAA ADC must provide high dynamic range, high linearity, good performance in presence of RFI and low added noise. These specifications may be seriously degraded by the large variation in spectral power density across the input band. This aspect is discussed here, together with the advantages and disadvantages of a whitening equalization filter.

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logosmallarcetri Arcetri Technical Report 1/2016


SKA Project Series
Effects of LFAA antenna amplitude and phase errors on the station beam

G. Comoretto

INAF Osservatorio Astrofisico di Arcetri

Abstract

LFAA stations must be calibrated to 0.5-1% to guarantee the dynamic range required by the science cases. This in turn poses constrains on the calibration of the individual station antennas. Given the measured performance of the antenna and receiver chain, especially below 100 MHz, this appears problematic.

In this report effects due to thermal expansion, to the polynomial fit on the receiver chain response, and to antenna-to-antenna variabilities are examined by simulation. Amplitude errors in the individual antennas produce a phase error in the station response, and phase errors both amplitude and phase response errors. To achieve 0.5% accuracy in the beam response individual antenna amplitude and phase errors must remain below 1 dB and 0.2 radians RMS.

Pdf version of this report