Glossary

Appendix

Non-drop frame mode

In this mode, drop frame mode processing is not performed. Since there is no frame cutting, a discrepancy of about 86 seconds occurs each day (in the case of a field frequency of 59.94 Hz) which causes problems when editing programs in units of seconds using the number of frames as a refernce.

See also Drop frame mode.

Preroll

The rewinding of a video tape in the player or recorder VTR by a certain length before an edit point, allowing the tape to attain a stable speed at the edit point and synchronization with the other video tape during editing.

Reference video signal

A video signal containing a sync signal or sync and burst signal, used as a reference for synchronizing video equipment.

Servolocking

The locking of the phase and speed of a VTR’s head drum rotation and tape transport to a reference signal during recording and playback.

Standby-off mode

A mode in which head drum rotation is stopped and tape tension is released, and thus the VTR is not ready for immediate recording and playback. This mode alleviates the tape and video heads from wear or damage.

Standby-on mode

A mode in which the head drum rotates with the tape wrapped around it, and thus the VTR is ready for immediate recording or playback. The VTR enters standby-off mode after remaining in standby-on mode for a specified length of time to prevent wear or damage to the tape and video heads.

Time code

A digital signal recorded on the video tape that supplies information such as hour, minute, second and frame number for each frame to facilitate the setting of edit points or searching for specific scenes on the tape.

There are two types of time codes: SMPTE (for the NTSC color system) and EBU (for the PAL/SECAM color system); and two time code recording formats: LTC (longitudinal time codes) which are CTL signals and audio signals simultaneously recorded longitudinally on the tape and VITC (vertical interval time codes) which are recorded on the video signal track.

Tracking

The synchronizing of the head drum rotation phase and tape transport phase during playback and recording. Tracking is adjusted to eliminate picture instability when playing back material recorded on another VTR.

User bits

A recordable 32-bit section in each time code on a video tape for recording such information as the recording year, month, and day, and the tape or program ID number.

Vertical interval time code

See VITC.

VITC

Abbreviation for Vertical Interval Time Code. This is a time code recorded on a video signal track during the vertical blanking interval. This VTR writes this time code in the AUX data area in the video signals. It can be read correctly even during slow or still picture playback. See also LTC.

A-34Appendix