Philips DVDR824P DVD+RW - Page 9

Writing Quality Tests - 3T Jitter Tests

We used 80min 48X CD-R media from Taiyo Yuden and burned the same AudioCD project at 8x, 16x, 24x, 32x and 40x. The following graph shows the results of the 3T Pit & Land Jitter tests.

- 3T Pit results

Generally, the drive did not fair well in the 3T pit jitter tests with the specific media. The highest 3T pit jitter was reported from the discs recorded at speeds of 32x and 40x, in the outer tracks. The jitter reached was around 45nsec, which is well above the Red Book limit of 35nsec. At the 20min mark for 24x speed, jitter increased sharply maintaining this level and then peaking near the end. The 32x and 40x speeds remained reasonably steady up until the 50 min mark and then peaked dramatically. 8x and 16x exhibited steady performance although they too were at or above the 35nsec mark near the end.

The average 3T Jitter values for all recording speeds are illustrated in the following table. Again, it shows how close these reading are to the Red Book limit of 35nsec.

- 3T Land results

The average 3T Land results presented in the graph above, are slightly increased over those in the previous measurements of the 3T Pit Jitter. Here once again the 32x and 40x discs gave high jitter especially in the outer tracks of the disc.

The 8x writing speed also seems to produce jitter higher than the nominal 35nsec, with the 16x speed being more preferable when writing audio CDs.

- Summary

The Optorite DD0401 did not give good results in the jitter measuring tests. In most cases, the jitter exceeded 35nsec indicating that there may be problems (bad quality). The tests on the following pages, where we check the C1 and C2 error rates for the same discs, will indicate just how much of a problem the drive may have.