1. Development of FFTS for Radio Astronomy Sheng Li, Zhen-Hui Lin, Ji Yang Wen-Ying Duan, Qi-Jun Yao, Sheng-Cai Shi Purple Mountain Observatory, Chinese Academy of Sciences Nov. 28 th, 2011 Sun-Moon Lake, Taiwan 2011 Advanced Telescope and Instrument Technology Conference

2. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 2 Requirement: Broadband & high resolution  Why broad bandwidth? Δ f/f o = Δv/c  For submillimeter-wave observation

3. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 3 Requirement: Broadband & high resolution  Why broad bandwidth? Δ f/f o = Δv/c  For high-redshift objects survey 100MHz bandwidth only covers ~300km/s!!! Credit: Young, J. S et al. 1984, ApJ, 287, 153

4. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 4 Requirement: Broadband & high resolution  Why high frequency resolution?  For observe fine structure of molecular lines  For knowing the kinematics characteristics of objects Credit: Schnee, S. et al. 2005, ApJ, 624, 254 N 2 H + (J=1-0) : 93.171621GHz 93.171917GHz 93.172053GHz 93.173480GHz 93.173777GHz 93.173967GHz 93.176265GHz

5. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 5 Evolvement: From analog to digital  Analog back-end system Filter Bank Spectrometer Acousto-Optical Spectrometer Filterbank & AOS 4x1GHz@1MHz Herschel HiFi

6. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 6 Evolvement: From analog to digital  Digital back-end system Auto/Cross-Correlation Spectrometer ALMA Correlator, 3bits or 2bits 8x2GHz@15.625MHz 8x250MHz@244kHz SMA Correlator, 2bits 8x24x82MHz@ 812.5 kHz

7. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 7 FFTS: Principle Autocorrelator/FFT Spectrometer

8. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 8 Spectral system evolvement at PMO AOS x 3 13.7m telescope at Delingha Single FFTS FFTS x 2 x 9 2006,08 2010,11

9. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 9 FFTS: Firmware development Firmware Structure based on AC240 Hardware structure of AC240AC240 Board

10. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 10 FFTS: Firmware development Parallel pipeline FFT core structure

11. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 11 FFTS: Firmware development Program language: VHDL Design tool: ISE 9.1 Resource utility

12. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 12 FFTS: Software development 设备初始化 图形界面创建 子线程创建 频谱及状态显示 标准源观测 谱线 OTF 观测 谱线 5 点观测 命令组接收 命令解析 数据发送 命令接收 数据发送 Human-computer interaction - Quicklook GUI Data processing – Multithreading （ 9 data processing sub-thread, 2 communication sub-thread ） Data Communication (TCP/IP, 1Gb/s) 、 Data Storage (NFS)

13. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 13 FFTS: Software development  Quicklook GUI Single FFTS 9-Pixel FFTS BECU case 1 BECU case 2

14. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 14 FFTS: Performance  Test results Integration Time: 32.768ms Dynamic Range: >30dB ADC Full Scale: 1V Stability/Allan-Variance: ~3000s

15. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 15 FFTS: Performance  Observation results SiO(2-1)

16. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 16 FFTS: Back-end system integration  Integration with data storage system Gigabits internet 20~40 MB/s data transfer rate with OTF 1Gb/s internet connection RAID-5 disk array for both high speed and reliability 34T bytes storage capacity (data of a month)

17. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 17 Future plan  Back-end for dome A telescope  Broadband with high resolution  Low power consumption  High level of integration  High stability  2011-2012, hardware, firmware & software development 2~2.5 GHz bandwidth, 16 k channels(122 kHz)  2013-2015 >=4 GHz bandwidth, >=32k channels Dome A Telescope

18. Nov. 28 th, 20112011 Advanced Telescope and Instrument Technology Conference 18 Thanks for your attention~