SKAO Pulsar Timing Processor
The Square Kilometre Array Observatory (SKAO) pulsar signal processor is capable of processing multiple phased-array beams, each with over 2 GHz of bandwidth.
Deployed at both the Australian and South African sites, the SKAO Pulsar Timing instrument (PST) interfaces with the correlator beamformer and receives up to 16 phased-array beams.
At the SKA1-Low Telescope, the PST receives 300 MHz of bandwidth, channelized into ~3.6 kHz fine channels, oversampled by 4/3 and quantized with 16 bits per sample. The maximum data acquisition rate is ~410 Gb/s.
At the SKA1-Mid Telescope, the PST receives up to 2500 MHz of bandwidth, channelized into ~16.3 kHz fine channels, oversampled by 8/7 and quantized with 8 or 16 bits per sample. The maximum data acquisition rate is ~1460 Gb/s.
The signal processing software executes on 16 servers, each equipped with two 100Gb Mellanox NICs and Nvidia GPUs that are connected via 100Gb switching infrastructure.
The SKAO PST implements five modes of operation.
Voltage Recorder
Records unprocessed baseband voltage data as received from the beamformer. This mode is used primarily during development, integration, verification and early commissioning.
Flow Through
Records decimated baseband voltage data, consisting of a subset of the fine channels with reduced number of bits per sample.
Detected Filterbank
Records full-polarization channelized time series with configurable temporal and spectral resolution.
Pulsar Timing
Performs phase-coherent dispersion removal and pulsar longitude-resolved integration of full-polarization data. This data stream supports high-precision pulsar timing experiments, including the international effort to detect low-frequency gravitational waves.
VLBI
Outputs a stream of VLBI Data Interchange Format (VDIF) compatible voltage data with configurable bandwidth and bits per sample.
For Detected Filterbank, Pulsar Timing and VLBI modes of operation, the channelization performed by the beamformer polyphase filter bank is inverted to increase the temporal resolution.