1. ACA TP Spectrometer Manabu Watanabe (NAOJ)

2. Overview of ACA TP Spectrometer
KASI and NAOJ have been collaboratively studying a software spectrometer for ACA TP-array since summer 2015.
The spectrometer software runs on a commercial server with GPUs.
All numerically intensive computations are offloaded onto GPUs.
32-bit floating point calculation
Higher sensitivity (4-bits re-quantization is no longer necessary).
Higher accuracy.
Effective observation (no correlator calibrations required)

3. ACA TP Spectrometer replaces TP array of ACA Corr.
ACA TP Spectrometer receives only TP-antenna signals
An optical signal splitter bifurcates TP-antenna signals
ACA TP Spectrometer and ACA Corr. share the TP-array
TP-antenna signals go into both
Only one of two runs on TP-array at one time
ACA TP Spectrometer makes ACA system simple
ACA Corr. on 7m-array
ACA Corr. on Full-array
ACA TP Spectrometer on TP-array
Improves the efficiency of operation

4. Block diagram DRXP: DTS receiver with PCIe bus interface
ACA Spectrometer Module: Commercial computer with GPU boards
ACA-TSC: ACA TP Spectrometer Computer (counter part of CCC and CDP master)

5. GPU server
ACA TP Spectrometer consists of 4 GPU servers.
Each GPU server digests 4 basebands (2-pol) from one antenna
GPU server has 4 GPU boards and 2 DRXP cards

6. Specifications are identical to those of ACA Corr.
Same SpectralSpec and same BDF as those of existing ACA Corr.
Data rate (up to 3.6 MB/sec)
Polarizations ({XX},{YY},{XX,YY},{XX,YY,XY})
Frequency channels (up to 8192)
Bandwidth (2GHz per baseband x 4 basebands)
Integration duration (up to 1ms)
Supports synthProf (compatible with BL Corr.)
To add a new processor type to APDM/ASDM
AUTO_ONLY mode

7. Impact on subsystems of ICT
CONTROL/SCHEDULING (3-FTE months/NA)
M&C Spectrometer
Add a new processor
(M&C DTS receiver/EA)
CASA/PIPELINE (12-FTE months/EA)
Support commissioning
TELCAL (Minor/EU)
OT/APDM (2-FTE months/EU)
Add a new processor type to APDM
ACA (2 or 3-FTE years/EA)
Development and test of ACA TP Spectrometer Computer

8. Milestones
2017 Feb PDR in Korea
2018 Apr CDR
2018 Nov PAI
2019 Jan PAS
2019 Feb AIV
2019 Apr CSV starts
2020 Oct Cycle 8 starts

9. The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.