FEATURES OF THE DIGITAL BACKENDS :
HARDWARE CORRELATOR :
- In order to cater protocluster search and the search for new short period PULSARS observations a spectroscopic CORRELATOR was built.Originally bandwidth specified was 16MHz. Later increased by a factor of 2 to 32MHz, to provide greater sensitivity for the PULSAR SEARCH and other studies. Also, the protocluster search requirement dictated a frequency resolution of at least 1MHz at 16MHz bandwidth. This meant that the CORRELATOR provide at least 16 spctral channels. However , for most spectral line observations and for pulsar studies, a larger number of spectral channels are required. For the GMRT CORRELATOR , a maximum of 256 channels specified.
The CORRELATOR was also required to provide a range of integration times to support various kinds of observations.
PULSAR RECEIVER :
- For studying the polarization properties of
the obseved source, the PULSAR RECEIVER was required to compute the Stokes parameters from the incoming data. The PULSAR RECEIVER was also required to provide a range of integration times to support various kinds of observations.
NEW HARDWARE CORRELATOR :
- More processing bandwidth using the latest FPGA technology in collaboration with SKA South Africa.
- 32 Stations , dual pol. correlator using CASPER tools.
SOFTWARE CORRELATOR :
GMRT SOFTWARE CORRELATOR BACKEND (GSB) :
- Better frequency resolution for full bandwidth case ie. longer FFT lengths.
- More Dynamic range ie. more bits per sample for better protection against radio frequency interference (RFI).
- Ability to filter out impulsive RFI and powerline RFI from raw data / visibility data.
- Ability to record raw data from each antenna and play back with different options.
- Ability to add new, sophisticated algorithms.
- Ability to form multiple beams within the primary beam (in phased array mode).