Case Studies
Charge-Couple Device Data Capture
The client is involved in developing a CCD-based system to function as an imaging spectrometer. The spectrometer will image 5x5 mm squares that will form a 50 mm line or 1.5x1.5 mm squares in a 15 mm line. The line is to be imaged on a CCD chip.
In this application the customer needs to simultaneously acquire 10 independent spectra that are 200 pixels long each with 12 bit resolution. The read-out rate is 1000 frames per second for a period of 10 seconds. The 12 bit data is to be stored on the computer to be processed later.
GAGE'S SOLUTION
Let's analyze the basic data acquisition requirements for this application.
First, the requirement for a single line must be determined as shown below:
200 points x 1000 frames/sec x 10 seconds = 2,000,000 samples
Once the data requirement is determined, the memory needed for this data has to be calculated. Since each sample is 12 bits which is stored in 2 bytes, the memory for this amount of data is 4Mbytes. In order to store ten lines, 40 Mbytes of memory is needed.
Normally images are captured one line at a time in sequence, but, in this case, there are ten lines of data to be captured simultaneously. This means that, instead of a single-channel acquisition system, the system has to be a ten-channel acquisition system.
The solution for this situation is a GagePC 586 industrial grade computer equipped with five CompuScope 512/ISA boards, with each board having 2 channels and 8M memory.
The 12 bit CompuScope 512 has the resolution needed and, at 5 MSPS, the speed to sample effectively. The 10 seconds of data can be stored in on-board memory prior to downloading to the computer for analysis.
Finally the computer must be equipped with a CompuPower DC-to-DC converter card to ensure that the cards have sufficient power on -12V and -5V power lines.
PRODUCT RECOMMENDED
Turnkey system:
- Gage PC 586 with CompuPower
- CompuScope 512 / ISA - 8M Master / Slave system for 5 cards
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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