PCInt requirement specification

The Post Correlator Integrator (PCInt) enhances the capability of the EVN MkIV Correlator by providing an output path for data rates that exceed the maximum transfer rate of the LAN. To achieve this the PCInt receives outputs from the correlator and performs various re-ordering and DSP functions. In general these processes will result in a reduction in the volume of data to be passed to an output port and/or data storage device.

As part of the requirement analysis several possible applications for the PCInt were identified. Each putting different contraints on the design.

• general application
• Pulsar Search Mode
• Multiple Field Centres
• Recirculation

• Fit within the Correlator design
• Receive control messages from the Correlator Control Computer (CCC)
• Interpret control messages to determine which of a defined set of processes is to be performed
• Receive multiple channels of correlator data
• Store and re-order the data as required
• Accumulate data as required
• Perform DSP algorithms such as complex multiplication and Fourier transformation as required
• Report status information to the CCC on request
• Pass the product of processing to TBD output port or removable storage media
• The storage media must have a large capacity to store several hours of observations

• input channels from 32 - C40 comm ports
• maximum data rate input channel 10 Mbytes/sec
• maximum overal input rate 320 Mbytes/sec
• 4 seperate units to handle 1 correlator unit each
• 8 input channels for each PCInt unit
• universal and common output port for each PCInt unit

• enough memory in each PCInt unit to handle a maximum of 16 field centres
• enough processing power to perform Complex vector multiplication, accumulation and Fourier transform