Case Studies
Ultra-High Speed RADAR
THE PROBLEM
This application requires the acquisition of very fast analog signals at relatively slow sample rates for a long period of time.
In other words, the input bandwidth requirement is very high (1 GHz), but the sampling rate needs to be no more than 5 or 6 MSPS. The most important requirement is that the acquisition must go on, without any breaks, for many hours.
The customer does not need very high dynamic range. In fact, a 4 bit A/D converter will be sufficient. The customer has already identified a 4 bit A/D chip from TRW which provides more than 1 GHz bandwidth.
The only remaining problem is how to acquire this huge amount of data (18 Gbytes / hour) into a PC at these rates while guaranteeing no missed data points.
GAGE'S SOLUTION
Although Gage cannot supply an A/D converter with 1 GHz bandwidth, the customer can use the TRW chip in its evaluation board (available from TRW) to do the actual sampling and then demultiplex the data and then send it to the CompuScope 8012/PCI - DIM for streaming the data to the host (PC) memory.
The CompuScope 8012/PCI - DIM is a digital input board for the PCI bus which is completely compatible with out-board A/D converters. By demultiplexing the data from a 4 bit wide sample to a 24 bit word, the customer can optimize the utilization of the memory, as the CompuScope 8012/PCI - DIM reads in 24 bits of data at a time.
At the software level, CompuScope 8012/PCI - DIM is identical to the CompuScope 8012/PCI board: the DIM module simply "fools" the system into believing that the data is coming out of the A/D chips on the CompuScope 8012, whereas it really is coming from the outside world, through the DIM module.
Demultiplexing will reduce the data transfer rate from 6 MSPS (4 bit samples ) to approximately 1 million 24 bit words per second. This data can now be transferred straight to a disk drive or other storage media using the PCI bus.
PRODUCT RECOMMENDED
CompuScope 8012/PCI - DIM
This application note is provided "as is" without any warranties of any kind, either expressed or implied, including but not limited to the implied warranties of merchantability or fitness for a particular purpose. Gage Applied Technologies further does not warrant the accuracy and completeness of the material contained herein. Gage Applied Technologies may make changes to this material, or to the products described in it, at any time without notice.
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