The Design And Realization Of The CD/DVD Jittermeter Calibrator

The paper deals in detail with the system design, the performance analysis and the application of the CD/DVD Jittermeter Calibrator. The complete set of instrument is composed of hardware and software. The crucial part of hardware is the circuit that generates standard jitter signal, HF pulse width modulation. The software consists of assemble lauguage programme, which is to keep the hardware under control, and Visual Basic programme, which is to realize the selection of function, the parameter setting, the calculation of control data and the RS232 serial communication. The technical difficulty, which should be settled in the study procedure, is the realisation of the HF high precision PWM. In this paper, it is complished by a unique method after researching the nowaday PWM technic and internal structure of the PWM chips. To generate the CD jitter signal, a Programmable Digital Potentiometer was used to change the external timer of High Speed CMOS Precision Monostable Multivibrator. To generate DVD jitter signal, it was complished by Digital Programmable Delay Generator, Digital Potentiometer and other logical parts. This kind of design broke through the weakness of the existing PWM technic which can only work normally under low frequency. Simultaneously, the high precision PWM was carried out by combining the accuracy of chips themselves and the amendment of software.The calibrator is a professional instrument and its output signal can fulfill the calibration of CD/DVD Jitter meter. Compared with other similar overseas product, there are many strongpoints. Its output signal has wide range of jitter, and the jitter can be adjusted continually. Moreover, the instrument offers three choices of jitter unit based on different uses. Because there is no any domestic institute or company and just very few Japanese company, which develops and produces this kind of instrument with high price, the successful development of CD/DVD Jittermeter Calibrator filled up the internal vacancy of this item, and broke the monopolization of domestic calibration market occupied by foreign equipments. The CD/DVD Jittermeter Calibrator has wide application outlook by creating extremely high benefit in both economical and social aspects.