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3  Backends

The only backends currently planned for LWA1 are the digital receiver Sect. 2.7 and the All-sky Imaging Backend Sect. 3.1. Other backends are anticipated and the project is open to proposals.

3.1  All-sky Imaging Backend (ASI)

The correlation of the data from the dipoles will occur through a software FX correlator, consisting of an IBM computing cluster. The data will come from the TBN and all baselines from the 256 dipoles can be processed.

Note: The ASI is under development during the first year of LWA1 operations and exists under the name of ’PASI’, Prototype All-Sky Imaging. PASI receives the TBN data stream of continuous 100 ksps data from all dipoles at 75 MHz. It splits the data into eight channels for imaging, and the firts and the last channel are discarded. PASI images most of the sky (∼1.5π sr) many times per minute at a 100% duty cycle.

PASI data is available for users, and can be requested together with a justification of the science. In addition, if other frequencies and/or integration times are desirable, a proposal can be submitted.

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