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Spectrometer (XFFTS)
This spectrometer is a control chassis which accomodate 8 FFTS cards, each with up to 2.5 GHz bandwidth. Each XFFTS-board operates from a single 5 Volt source and dissipates less than 30 Watt, depending on the actual configuration in terms of bandwidth and number of spectral channels. Precise time stamping of the processed spectra is realized by an on-board GPS/IRIG-B time decoder. Furthermore, the 10-layer boards include a programmable ADC clock synthesizer for a wide range of configurations (bandwidth: 0.1 – 2.5 GHz), making the spectrometer flexible for different observation requirements .
| The XFFTS-boards include a standard 100 MBit/s Ethernet interface, which simplifies the combination of many boards into an Array-XFFTS, simply by integration of a common buffered Ethernet switch. Up to eight XFFTS-boards can be housed in one XFFTS-crate together with power supplies (4 × 5 Volt / 20 Amperes) and one XFFTS-controller. The XFFTS-controller manages the synchronization of the XFFTS-boards. It provides a reference clock for the on-board ADC synthesizers or the GPS/IRIG-B timing information. In addition, the XFFTS-controller displays housekeeping information on a four line LCD, like board IP numbers, temperatures of the ADC and FPGA chips as well as the power level of the IF inputs. |
Features:
- Maximum instantaneous bandwidth: 2.5 GHz
- Up to 32768 spectral channels at full bandwidth
- Equivalent noise bandwidth (polyphase filter-bank):88 kHz @ 2.5 GHz bandwidth / 32768 spectral channels
- On-board Ethernet Interface (100Base TX) for spectral readout and FFTS board configuration
- Input for external control signals: blank, sync, frequency reference
- Remote programmable FPGA (Xilinx Virtex6 LX240T)
- Precise time stamping of the processed spectra by on-board IRIG-B time-stamp encoding
| Signal Input | |
|---|---|
| Full Power Bandwidth (-3dB) | 0.1 GHz to 2.5 GHz (for further details contact RPG) |
| Input Power | full scale input power: -2dBm (500mVpp) |
| Max. Input Voltage | ±2 VDC |
| Impedance | 50 Ω |
| Input Coupling | AC (Balun) |
| Input Connector | SMA (gold plated) |
| Digital Conversion | |
| ADC Type | E2V EV10AQ190 |
| Sample Rate | up to 5 GSPS |
| ADC Resolution | 10 bit (-512 to +511) |
| ENOB , full bandwidth | 7.6 @ 620 MHz 7.2 @ 1200 MHz |
| SFDR (typical) | > 57 dBc @ 620 MHz > 55 dBc @ 1200 MHz |
| Differential Nonlinearity | ±0.3 LSB |
| Integral Nonlinearity | ±0.8 LSB |
| Reference Frequency Input (FFTS Controller) | |
| Ext. Clock/Ref. Threshold | 800mVpp |
| Maximum Input Voltage | 3.0 Vpp |
| Reference Frequency Range | 5 to 250 MHz (5MHz step size, programmable) |
| Input Connector | SMA (gold plated) |
| Time Base | |
| Clock Accuracy | ±50 ppm (FFTS Controller) |
| Sampling Jitter | < 500fs RMS (10µs record length) |
| On-Board GPS/IRIG-B Time Decoder | |
| Standard | IRIG-B 12x, 1kHz, AM modulated |
| Accuracy (decoding) | < 50µs |
| On-Board Ethernet Interface | |
| Standard | IEEE 802.12 (100MBit/s) |
| Data Rate | 80 Mbit/s, sustained |
| On-Board Data Processing Unit (DPU) | |
| FPGA (main DPU) | XILINX Virtex-6 XC6VLX 240T |
| FPGA (Ethernet, etc.) | XILINX Spartan-3 XC3S 1000 |
| Signal Processing / Alogorithm | polyphase filter bank (fft) |
| Bandwidth (BW) | 2.5GHz (default) |
| Spectral Channels | 32768 (32K) @ 2.5GHz BW |
| Channel Spacing | 76.3 kHz @ 2.5GHz BW |
| Resolution (ENBW) | 88.5 kHz @ 2.5GHz BW |
| Processing Output | 32-bit single precision (float, IEEE-754) |
| Spectral Dump Time | max. 5s min. 20ms @ 32k channels |
| PC System Requirements | |
| Processor (CPU) | Pentium 4 (2GHz or higher) Dual Core CPU recommended |
| Memory | 1 Gb RAM (mroe recommendes when working with several XFFTS boards) |
| Operating System | Linus (Kernel 2.6) |
| Hard Drive Space | min. 300 MB |
| Ethernet Switch | A managed Ethernet switch capable pf bufferung data for each Ethernet port is recommended. |
| General data | |
| Environmental Conditions | indoor use only |
| Operating Temperature Range | 0°C to 40°C |
| Storage Temperature | -30°C to 60°C |
| Operation Altitude | 3000 m (contact RPG for further details) |
| Required Airflow | >2 m/s |
| Relative Humidity | 5-90% (non condensing) |
| Power supply | |
| AC Supply | 108VAC to 120VAC & 216VAC to 240VAC 50Hz to 60Hz (auto adjust) |
| Power Consumption | max. 200W (depending on FPGA core version and operation mode); 4 internal power supplies 5VDC/20A |
| Dimensions (wxhxd) | 480 x 135 x 485mm 19" crate, 3 units height standard crate, rack mount |
| Weight | max. 13kg |
PRG_XFFTS Datasheet_2015.pdf
XFFTS Manual_2015.pdf
Atacama Pathfinder Experiment-MPI-ICD-0005-R1_0.pdf
Astronomy&Astrophysics Special Feature (XFFTS, B.Klein et al.pdf
B. Klein XFFTS (ISSTT, Charlottesville).pdf.safe.pdf
B. Klein et al High resolution wide band FFTS (1203.3972v1).pdf
FFTS-Poster2013_e.pdf.safe.pdf