| Japanese |
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K5/VSSP(*) and K5/VSSP32 are high-performance samplers dedicated to a geodetic VLBI system
developed by the Kashima VLBI group of
National Institute of Information and Communications Technology (NICT).
K5/VSSP sampler is a PCI bus board mountable on a motherboard of standard PC
and has a maximum sampling frequency of 16 MHz per channel. Any PC equipped with a K5/VSSP PCI-bus
board can be a VLBI recorder, and the data transfer through the Internet is easily realized.
K5/VSSP32 is a successor to the K5/VSSP, but a USB 2.0 is adopted as an interface with a host PC.
Maximum sampling frequency per channel is increased up to 64 MHz. As both K5/VSSP and VSSP32 units has 4 channel
analog inputs, 4 units can cover 16 channels which is sufficient number of channels in case of geodetic VLBI.
Adoption of USB2.0 interface enables us to use a notebook or laptop PC as a host PC of the sampler.
Thus K5/VSSP32 can be used for a not only a VLBI observation but also a general-purpose geophysical
observation which requires precise time label.
Recently K5/VSSP64 became available to use. It is a scuceessor to the K5/VSSP32 and
has a maximum sampling frequency of 128 MHz per channel. A USB 3.0 is adopted as an interface with a host PC.
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| K5/VSSP Sampler Board | K5/VSSP32 Sampler Unit | K5/VSSP64 Sampler Unit |
|---|---|---|
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| K5/VSSP sampler board | K5/VSSP32 sampler unit | K5/VSSP64 sampler unit | |
|---|---|---|---|
| Sampling frequency (MHz) | 0.04, 0.1, 0.2, 0.5, 1, 2, 4, 8, 16 | 0.04, 0.1, 0.2, 0.5, 1, 2, 4, 8, 16, 32, 64 | 2, 4, 8, 16, 32, 64, 128 |
| Built-in digital LPF (MHz) | ---- | 2, 4, 8, 16, through | 2, 4, 8, 16, 32,through |
| Analog Input range | -1V - +1V | -1V - +1V | -0.8V - +0.8V |
| Analog band width of AD converter | 100 MHz | 300 MHz | 1250 MHz |
| AD resolution (# of bit) | 1, 2, 4, 8 | 1, 2, 4, 8 | 1, 2, 4, 8 |
| # of channel per board (unit) | 1, 4 | 1, 4 | 1, 2, 4 |
| Maximum data rate per board (unit) | 64 Mbps | 256 Mbps | 1024 Mbps |
| DC offset adjust | NA | available from a host PC | available from a host PC |
| Reference signals | 1PPS, 10MHz | 1PPS, 10MHz or 5MHz | 1PPS, 10MHz or 5MHz |
| Interface to PC | PCI bus | USB 2.0 | USB 3.0 |