• Digital Terrestrial Broadcasting
• JITTER MEASUREMENTS "DVD-RAM Jitter Analyzing Technique"

Introduction

Digital Processing Jitter Analyzer
LE 1875 (S1 version)

Leader Electronics Corp. has sold the Jitter Analyzer from the appearance of music CD in 1982 as a basic measuring instrument for optical discs.
The optical discs grow up from a music CD to CD-ROM as media for recording the information on the computer. DVD then became familiar in the latter half of 90's as media for recording the image.
Such write-enabled discs as DVD-R/RW and DVD-RAM are recently commercialized as a successor of VTR and are used widely.

The jitter measuring instrument now provides the high performance capability and various functions according to the evolution of the optical disc.

Our LE 1875 Digital Processing Jitter Analyzer (S1 version) is a completion type of the jitter measuring instrument, such write-enabled discs as DVD-RAM, DVD-RW, and CD-RW can be measured as well as DVD-ROM and CD-ROM.

This Technical Information introduces "DVD-RAM Jitter Analyzing Technique" with the LE 1875 (S1 version) that promptly responded to the DVD-RAM and diversified jitter measurement methods.

1. Various Discs and Measurement Methods

The edge of pit recorded on the optical disc is used to measure jitter.

The 3T method (i.e., measures jitter of a minimum pit) is used as a jitter measurement method for CD.
To measure jitter of high density DVD, the all-T method (i.e., measures all pits of 3T to 11T and 14T) prescribed by the DVD Book (Specifications) is used.

The CD-ROM used as media for recording the information on the computer is demanded the high-speed jitter measurement capability due to a requirement of high-speed reading operation.

To measure write-enabled discs, a variety of jitter measurement functions such as biphase signal (used for writing address signal to a CD-R) measurement function, the sum of all-T components measurement function for DVD-RW, and the period measurement function for DVD-RAM are required.

To measure the jitter of the DVD optical pickup, one-signal measurement method used for a CD came to be demanded from a past two-signal measurement method by using a TIA. Therefore, the jitter analyzer now provides the internal clock regenerator.