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Broadband F ast F ourier T ransform S pectrometer ( FFTS )

Broadband F ast F ourier T ransform S pectrometer ( FFTS ). Bernd Klein Max-Planck-Institut für Radioastronomie, Bonn - Germany -. B.Klein Berkeley 2008. 2.5. 2.0. 1.5. instantaneous bandwidth [GHz]. 1.0. 0.5. 0.1. year. 2003. 2004. 2005. 2006. 2007. 2008. 2009.

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Broadband F ast F ourier T ransform S pectrometer ( FFTS )

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  1. Broadband Fast Fourier Transform Spectrometer(FFTS) Bernd Klein Max-Planck-Institut für Radioastronomie, Bonn - Germany - B.Klein Berkeley 2008

  2. 2.5 2.0 1.5 instantaneous bandwidth [GHz] 1.0 0.5 0.1 year 2003 2004 2005 2006 2007 2008 2009 FFTS::A short “history” ... 2.5 GHz>8k channels 1.5 GHz8k channels 1 GHz8k channels 1.8 GHz8k channels 100 MHz? channels 2 x 50 MHz1k channels B.Klein Berkeley 2008

  3. GPS/IRIG-BTime decoder Analog Power Supply 5 Volt FPGASignal pro-cessing ADC Data Power Supply(1.2, 1.9, 2.5, 3.3 V) 100 MBit/sEthernet ADCSynthesizer (AD9517-n) FFTS ::The MPIfR-Board IF input(0 - 3 GHz) • Instantaneous bandwidth: 0.1 – 1.8 GHz • Spectral resolution @ 1.5 GHz: 212 kHz • Stability (spec. Allan Variance): > 1000 sec. • Calibration- and aging free digital processing B.Klein Berkeley 2008

  4. ADC Transistor as „Heater“ FFTS ::Stability The spectroscopic variance between two 1 MHz broad channels, separated by800 MHz within the band, was determined to be stable on a timescale of ~4000 s. B.Klein Berkeley 2008

  5. APEX ::Atacama Pathfinder EXperiment Telescope: Location: Llano de Chajnantor, 50 km east San Pedro de Atacama, northern Chile Coordinates: Latitude : 23º00"20.8' South Longitude :67º45'33.0" West Elevation : 5105 m Diameter: 12 m f/D: 8 Beam width: (FWHM) 7.8" * (800 / f [GHz]) Main reflector: 264 aluminum panels, average panel surface rms 5 micron Surface accuracy: 17 micron rms Pointing accuracy: 2" rms over sky Mounting: Alt-Az Receiver cabins: 2 Nasmyth + 1 Cassegrain Mass: 125 000 kg Manufacturer: Vertex Antennentechnik B.Klein Berkeley 2008

  6. CHAMP+ :: Array-RX 660/850 GHz window B.Klein Berkeley 2008

  7. AFFTS ::Array-FFTS for APEX Bandwidth: 32 x 1.5 GHz = 48 GHz (option 58 GHz) Spec. channels: 32 x 8k = 256k channels @ 212 kHz B.Klein Berkeley 2008

  8. AFFTS ::FFTS-Master B.Klein Berkeley 2008

  9. AFFTS ::Software / Monitoring • FFTS Control Software: • multi-threaded software / Linux • one thread per FFTS-board (smoothing, leveling, RFI-filter, ..) • communication telescope / FFTS: SCPI protocol (UDP/ASCII), e.g.APEX:AFFTS:band1:cmdBandwidth 1500 • data flow: TCP (header + spectra) • FFTS Monitor Tool (LabView) test line @ 300 MHz B.Klein Berkeley 2008

  10. The Lab-FFTS B.Klein Berkeley 2008

  11. Frequency response of the optimized FFT signal processing pipeline FFTS ::Signal Processing Unlike the conventional windowed-FFT processing, a moreefficient polyphase pre-processing algorithm has been de-veloped with significantly reduced frequency scallop, lessnoise bandwidth expansion, and faster sidelobe fall-off. Equivalent noise bandwidth = 1.16 x frequency spacing B.Klein Berkeley 2008

  12. 1.9 GHz is possibleby using selectedFPGAs with highestspeed grades! FFTS ::FPGA configurations Today, implemented FFTS board / FPGA configurations are: • 1 x 1.5 GHz bandwidth, 1 x 8192 spectral channels, ENBW: 212 kHz (default core) • 1 x 1.8 GHz bandwidth, 1 x 8192 spectral channels, ENBW: 255 kHz • 1 x 750 MHz bandwidth, 1 x 16382 spectral channels, ENBW: 53 kHz • 1 x 500 MHz bandwidth, 1 x 16384 spectral channels, ENBW: 35 kHz • 1 x 100 MHz bandwidth, 1 x 16384 spectral channels, ENBW: 7 kHz (in lab test) • 2 x 500 MHz bandwidth, 2 x 8192 spectral channels, ENBW: 71 kHz (in lab test) The Equivalent Noise Bandwidth (ENBW) is the width of a fictitious rectangular filter such that the power in that rectangular band is equal to the (integrated) response of the actual filter. B.Klein Berkeley 2008

  13. W3(OH) Spectrum towards Orion-KL. The high-excitationCO(7-6) transition at 806 GHz was observed withthe central pixel of the CHAMP+ array. SgrA circum-nuclear disk CO(2–1) FFTS ::in world-wide use The superior performance, high sensitivity and reliability of MPIfR FFT spectrometershas now been demonstrated at many telescopes world-wide. • Furtherdetails: • B. Klein, et al., Proceedings of the 19th • ISSTT, Groningen 28-30 April 2008 • http:://www.mpifr-bonn.mpg.de/staff/bklein B.Klein Berkeley 2008

  14. Applications: • Spectroscopy :: 16 x 100 - 500 MHz bandwidth, 8192 and 16384 channels • Pulsar Search :: 16 x 250 MHz bandwidth, 512 channels, 32/64µs dumping The Effelsberg FFTS (EFFTS) Installation & Commissioning: August this year! B.Klein Berkeley 2008

  15. Board modifications: • Dual input ADC :: National ADC08D1500, 2 x 750 MHz bandwidth • GigaBit Ethernet :: Marvell 88E1111, UDP: 85 MBytes/sec cont. I-Input Q-Input TCP 100 Mbits/s UDP 1 Gbits/s Marvell GigaBit chip The Effelsberg FFTS :: hardware B.Klein Berkeley 2008

  16. EFFTS :: pulsar signal processing Performance: • FPGA processing :: 250 MHz bandwidth & 8-tab polyphase filterbank with 512 channels, ENBW: 515 kHz • Dump time[µs] :: 32, 64 or 128, 16 x 512 channels (32-bit float) • 1k Bytes tail (dump counter, GPS/IRIG-B time,...) • Data rate @ 32µs :: ~64 MBytes/sec B.Klein Berkeley 2008

  17. FFTS :: The 2.5 GHz development Currently in development:The 2.5 GHz bandwidth FFTS for GREAT Goal:2.5 GHz instantaneous bandwidth with adequate spectral resolution (~100 kHz), to be operational in time for SOFIA‘s early science flights in summer 2009! B.Klein Berkeley 2008

  18. 2.5 GHz Bandpass (on-off)/off + test line @ 2.4 GHz FFTS :: The 2.5 GHz development First (lab) results: 2.5 GHz with 512 channels Next step: Increase the number of spectral channels by replacing the Virtex-4 SX55 by the new Virtex-5 SX240T or 3/4 x Virtex-4 SX55. B.Klein Berkeley 2008

  19. MPIfR FFTS :: Summary Advantages of our new generation of compact FFT spectrometers: • FFTS provide high instantaneous bandwidth (1.5/1.8 GHz demonstrated in field tests, 2.5 GHz achieved in lab tests) with many thousands frequency channels, thus offering wideband observations with high spectral resolution without the complexity of the IF processing in a hybrid configuration. • They provide very high stability by exclusive digital signal processing. Allan stability times of > 1000 seconds have been demonstrated routinely. • Field-operations of our FFTS over the last 3 years have proven to be very reliable, with calibration- and aging-free digital processing boards, which are swiftly re-configurable by Ethernet for special observation modes. • Low space and power requirements – thus safe to use at high altitude (e.g. APEX at 5100-m) as well as (potentially) on spacecrafts and satellites. • Production cost are low compared to traditional spectrometers through use of only commercial components. B.Klein Berkeley 2008

  20. http://www.radiometer-physics.de FFTS ::Contact, Distribution Contact:For further information about the MPIfR FFT spectrometer technology,future developments and applications, please contactBernd Klein (bklein@mpifr.de) at theMax-Planck-Institut für Radioastronomie in Bonn, Germany. http://www.fft-spectrometer.info Distribution of standard FFT spectrometer (1.5 GHz / 8192 channels) by: B.Klein Berkeley 2008

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