IEC 60843-4 pdf download

IEC 60843-4 pdf download Helical-scan video tape cassette system using 8 mm magnetic tape (8 mm video) – Part 4: Video subcode (VSC)
1 General
1.1 Scope
This part of lEC 60843 specifies a method of auxiliary data recording and playback withthe IEC 60843 8 mm video system.This part is applicable to both 525 line -60 field and625 line – 50 field television systems.
1.2 Normative references
The following normative documents contain provisions which, through reference in this text,constitute provisions of this part of lEC 60843.For dated references, subsequent
amendments to, or revisions of, any of these publications do not apply. However, parties toagreements based on this part of lEC 60843 are encouraged to investigate the possibility ofapplying the most recent editions of the normative documents indicated below.For undatedreferences, the latest edition of the normative document referred to applies. Members of lECand lso maintain registers of currently valid lnternational Standards.
IEC 60461:1986,Time and control code for video tape recorders
IEC 60843 (all parts), Helical-scan video tape cassette system using 8 mm magnetic tape
2Area allocation and dimensions
2.1 Types of video subcode (vsc)
There are two types of vSC which are 1 block vsC and 5 block vSc.
2.21 block vsc
Figure 1 shows the recording area of 1 block vSc.
The recording area of 1 block VSC shall be specified by the head switching point.
All of the data area, search mark and erase code should be recorded.
2.35 block vsc
2.3.1 5 block vsC with PCM audio
Figure 2 shows the recording area of 5 block VSC with PCM audio.
The recording area of 5 block VSC with PCM audio shall be specified by the distance from thehead switching point.
All the data area, search mark and erase code should be recorded.
The erase code should have a variable length relative to the position of PCM data area.
2.3.2 5 block vsC without PCM audio
Figure 3 shows the recording area of 5 block vsC without PCM audio.
The recording area of 5 block vSC without PCM audio shall be specified by the distance fromthe head switching point.
All of the data area, search mark and erase code should be recorded.
Data structure
3.1 1 block vsc
Figure 4 shows the data area of 1 block vSc.
1 block vsc consists of a block named Block 4.
Block 4 is common to 5 block vsc and 1 block vsc.
3.25 block vsc
Figure 5 shows the data area of 5 block vsc.
5 block vsC has an extended data area from Block 0 to Block 3.
Channel coding
4.1 Modulation
The modulation method shall be a bi-phase mark, except for the synchronization code.
4.2Transmission rate
The transmission rate shall be 368 times the horizontal sync frequency,5,79 Mbit/s for the525 line – 60 field system and 5,75 Mbit/s for the 625 line – 50 field system.