| Table of Contents |
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Introduction
This page helps researchers understand the different modes and data rates of the new MWAX Correaltor and Voltage Capture System (VCS) at a time when the number of used tiles in the MWA is expanding beyond the original 128T (128 tiles) which has been the standard since science commissioning in 2013. With the advent of new receivers, MWA will incrementally expand the number of tiles (nominally 8 per receiver) over time time of Phase 3.
Voltage Capture System (VCS)
VCS Modes
The
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- 128T (16 RRI receivers)
- 24 x 1.28 MHz non-oversampled coarse channels
- No fringe-stopping enabled
Voltage Capture (VCS)
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MWAX VCS system has the following modes:
- MWAX_VCS - This is the standard voltage capture mode where incoming voltages from the receivers are written to disk (each MWAX server writes 1.28 MHz of the 30.72 MHz bandwidth).
- MWAX_BUFFER - In this mode, voltages are captured from receivers, but not written to disk unless triggered to do so by the M&C system (this could be via a VO event trigger or with human intervention).
VCS Data Rates
The below table summarises the Voltage Capture (VCS) data rates with 1.28 MHz channels, 0.781 μs critically sampled.
| 1 Channel | 24 Channels | |||
|---|---|---|---|---|
| Tiles | GB/s | TB/hr | GB/s | TB/hr |
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| 128 | 0.66 | 2.37 | 15.83 | 56.98 |
| 136 | 0.70 | 2.52 | 16.82 | 60.54 |
| 144 | 0.74 | 2.67 | 17.81 | 64.10 |
Correlator
Correlator Modes
The MWAX Correlator has been designed to be flexible with the frequency and time averaging modes available to researchers. Each mode combines a frequency averaging setting and an time averaging setting.
| Note |
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The MWAX software is flexible and is able to handle all available modes, but is limited by the hardware the software runs on. As a result, for any particular MWA configuration of N tiles, not all modes are able to be run in real time. |
Frequency:
Fine Channel Width (kHz) | 0.2 | 0.4 | 0.8 | 1.0 | 1.6 | 2.0 | 3.2 | 4.0 | 5.0 | 6.4 | 8.0 | 10.0 | 12.8 | 16.0 | 20.0 | 25.6 | 32.0 | 40.0 | 51.2 | 64.0 | 80.0 | 128.0 | 160.0 | 256.0 | 320.0 | 640.0 | 1280.0 |
| Number of fine channels per coarse | 6400 | 3200 | 1600 | 1280 | 800 | 640 | 400 | 320 | 256 | 200 | 160 | 128 | 100 | 80 | 64 | 50 | 40 | 32 | 25 | 20 | 16 | 10 | 8 | 5 | 4 | 2 | 1 |
Time:
Integration time (seconds) | 0.25 | 0.50 | 1.0 | 2.0 | 4.0 | 8.0 |
Correlator Data Rates
Legend:
The value in each cell is the total of all data from all coarse channels, in gigabytes, generated in 1 second (GB/s). Multiply by the duration of your observation to get total size of your observation in the mode chosen.
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| Info |
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Note: when in extended / long baseline configuration, most science cases will require the 10 kHz, 0.5 sec mode at a minimum until the fringe stopping feature is enabled |
Modes
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at 128T
| cell values = Total data size (GB/s) | Time Resolution (s) | |||||||
|---|---|---|---|---|---|---|---|---|
fscrunch | fine chans per coarse | fine chan width kHz | 0.25 | 0.5 | 1.0 | 2.0 | 4.0 | 8.0 |
| 1 | 6400 | 0.2 | 161.69 | 80.85 | 40.42 | 20.21 | 10.11 | 5.05 |
| 2 | 3200 | 0.4 | 80.85 | 40.42 | 20.21 | 10.11 | 5.05 | 2.53 |
| 4 | 1600 | 0.8 | 40.42 | 20.21 | 10.11 | 5.05 | 2.53 | 1.26 |
| 5 | 1280 | 1.0 | 32.34 | 16.17 | 8.08 | 4.04 | 2.02 | 1.01 |
| 8 | 800 | 1.6 | 20.21 | 10.11 | 5.05 | 2.53 | 1.26 | 0.63 |
| 10 | 640 | 2.0 | 16.17 | 8.08 | 4.04 | 2.02 | 1.01 | 0.51 |
| 16 | 400 | 3.2 | 10.11 | 5.05 | 2.53 | 1.26 | 0.63 | 0.32 |
| 20 | 320 | 4.0 | 8.08 | 4.04 | 2.02 | 1.01 | 0.51 | 0.25 |
| 25 | 256 | 5.0 | 6.47 | 3.23 | 1.62 | 0.81 | 0.40 | 0.20 |
| 32 | 200 | 6.4 | 5.05 | 2.53 | 1.26 | 0.63 | 0.32 | 0.16 |
| 40 | 160 | 8.0 | 4.04 | 2.02 | 1.01 | 0.51 | 0.25 | 0.13 |
| 50 | 128 | 10.0 | 3.23 | 1.62 | 0.81 | 0.40 | 0.20 | 0.10 |
| 64 | 100 | 12.8 | 2.53 | 1.26 | 0.63 | 0.32 | 0.16 | 0.08 |
| 80 | 80 | 16.0 | 2.02 | 1.01 | 0.51 | 0.25 | 0.13 | 0.06 |
| 100 | 64 | 20.0 | 1.62 | 0.81 | 0.40 | 0.20 | 0.10 | 0.05 |
| 128 | 50 | 25.6 | 1.26 | 0.63 | 0.32 | 0.16 | 0.08 | 0.04 |
| 160 | 40 | 32.0 | 1.01 | 0.51 | 0.25 | 0.13 | 0.06 | 0.03 |
| 200 | 32 | 40.0 | 0.81 | 0.40 | 0.20 | 0.10 | 0.05 | 0.03 |
| 256 | 25 | 51.2 | 0.63 | 0.32 | 0.16 | 0.08 | 0.04 | 0.02 |
| 320 | 20 | 64.0 | 0.51 | 0.25 | 0.13 | 0.06 | 0.03 | 0.02 |
| 400 | 16 | 80.0 | 0.40 | 0.20 | 0.10 | 0.05 | 0.03 | 0.01 |
| 640 | 10 | 128.0 | 0.25 | 0.13 | 0.06 | 0.03 | 0.02 | 0.01 |
| 800 | 8 | 160.0 | 0.20 | 0.10 | 0.05 | 0.03 | 0.01 | 0.01 |
| 1280 | 5 | 256.0 | 0.13 | 0.06 | 0.03 | 0.02 | 0.01 | 0.01 |
| 1600 | 4 | 320.0 | 0.10 | 0.05 | 0.03 | 0.01 | 0.01 | 0.01 |
| 3200 | 2 | 640.0 | 0.05 | 0.03 | 0.01 | 0.01 | 0.01 | 0.01 |
| 6400 | 1 | 1,280.0 | 0.03 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 |
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