1. Correlator – Backend System Overview
14-15 May, 2002
Correlator - Backend System Overview

2. Correlator - Backend System Overview
Major Components
Correlator
M & C
Backend
The dashed lines surround the components of the Correlator System. Lag frame data (wide arrows) flows from the Correlator to the Backend and then on to the End-to-End System. Control and other data (control commands, status reports, error messages, metadata, etc. – thin arrows) flows among the various systems, but the Backend communicates directly only with the Monitor and Control (M & C) System.
e2e
14-15 May, 2002
Correlator - Backend System Overview

3. Correlator - Backend System Overview
14-15 May, 2002
Correlator - Backend System Overview

4. Correlator-Backend Network
160 (27-32 Antennas) Minimum to 336 (48 Antennas) Correlator Connections
~50 Backend Connections
Maximum Aggregate Transfer Rate of 1.6 Gbytes /sec
Gbit / sec switch
14-15 May, 2002
Correlator - Backend System Overview

5. Correlator - Backend System Overview
Backend to e2e Network
Maximum Aggregate Transfer Rate of 25 Mbytes / sec
~ 50 Backend Connections
Network vs. Direct Channel Attached to Archive System
14-15 May, 2002
Correlator - Backend System Overview

6. Correlator - Backend System Overview
Observational Modes
Continuum
Spectral Line
Pulsar
Bursting
Sub-array
14-15 May, 2002
Correlator - Backend System Overview

7. Correlator - Backend System Overview
Output Data Frames
266, 32-Bit Words (1064 Bytes)
1 or More Frames per Packet
Frames Include all Data Needed For Lag Set Assembly
All Frames From Same Baseline go to One BE Processor
14-15 May, 2002
Correlator - Backend System Overview

8. Direct Correlator Data Products
Antenna ID
Baseband ID
Sub-band ID
Recirculation Block Number
Frame Count
Status Bits
14-15 May, 2002
Correlator - Backend System Overview

9. Direct Correlator Data Products
Phase Bin Number
Sample Valid Count
Time Stamp
Checksum
Correlation Lag Values
14-15 May, 2002
Correlator - Backend System Overview

10. Correlator - Backend System Overview
Correlator Lag Values
In-phase and Quadrature
Stored as Real And Imaginary Pairs
32-bit, 2’s Complement Integers
14-15 May, 2002
Correlator - Backend System Overview

11. Correlator - Backend System Overview
Indirect Data
State Counts (Correlator Produced)
Correlator Configuration
Integration Rate
Processing Applications and Parameters
Meta Data Needed for Formatting
14-15 May, 2002
Correlator - Backend System Overview