Strategic Test Enables Up to 270 Oscilloscope PCI Cards to Be Synchronized across Multiple PCs

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Strategic Test has introduced the System Star Hub option for the UltraFast Oscilloscope/Digitizer, AWG and Digital I/O and Digital Pattern Generator PCI cards. For the first time, this allows up to 270 cards installed in multiple PCs to be synchronized allowing systems with up to 4336 analog channels or 8672 digital channels. The System Star Hub distributes a common sampling clock and trigger bus across up to 17 PCs. The System Star Hub Master option is installed on one UltraFast card in the main PC and System Star Hub Slave options are installed on one card in the remaining PCs. Master and Slaves are then cabled together externally. The maximum distance between each pair of PCs is 2 meters.

Different types of cards can be used together to create systems with Oscilloscopes, Arbitrary Waveform Generators, high-speed Digital I/O or Digital Pattern Generators. Not all cards have to use the same sampling rate, as the master sampling clock can be divided uniquely on each card.

The System Star Hub also has the advantage of using the combined PCI bus bandwidths across all PC's to achieve a much higher streaming rate throughout the system. When one PC is used, the PCI bus has a maximum continuous transfer rate of 100 MBytes per second. This bandwidth is shared by all cards installed and has the effect of limiting the maximum sampling rates of the cards.

For example, when using 8-bit resolution the maximum sampling rate of ten channels when streaming would be 100 MSamples per second, or 10 MSamples per second per channel. However, if ten cards each with single channel were distributed in ten PC's, each channel could reliably stream up to 100 MSamples per second. Maximum sampling rates are not limited if the signals are recorded to card memory without streaming. However, the time to offload the data at the end of the measurement is extended due to the same bandwidth limitation issues.

The System Star Hub performance will increase in the future. The UltraFast PCI cards are also compatible with the PCI-X (66 MHz PCI bus) that has a maximum continuous transfer rate of 225 MBytes per second (2.25 times faster than 33 MHz PCI). Unfortunately, no motherboards exist today with more than a few PCI-X slots. As these do become available, the streaming performance across a System Star Hub configuration will increase.

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