Design of CCD driver for quartz horizontal pendulum tiltmeter based on CPLD

Abstract

In order to improve the resolution and conversion speed of photoelectric transducer, a high sensitive and low dark current CCD image sensor TCD1711DG was used in SQ-70D digital quartz horizontal pendulum tiltmeter. The timing chart of CCD has fixed state transition and rigorous timing requirements at typical pulse frequency. Then, a method of controlling the pulse state transition was developed by synchronous counting. The driver was carried out by using Verilog HDL based on CPLD. Simulation and experimental results indicated that the driver designed by this method was simple and stable enough to meet the timing requirements of TCD1711DG. Furthermore, integration time of the CCD could be revised flexibly by setting controlled variable QINT which improved the adaptability of the tiltmeter to different lighting levels.