F3 -Frame

A group of 33 8-bit bytes, being an F2 -Frame with a control byte, and input to a 8-to-14 encoder.

A single byte called Control byte is added as first byte to each F2 -Frame of 32 bytes. This yields a new F3 -Frame of 33 bytes. The information in the Control bytes is mainly used for addressing purposes. The bytes in the table are added to 98 consecutive F2 -Frames, coming out of the CIRC encoder, byte 0 of the table first, byte 97 last. This operation yields groups of 98 F3 -Frames of 33 bytes each, called Sections. These Sections are asynchronous with the Sectors, i.e. there is no prescribed relation between the number of the F1 -Frame in which the first byte of a Sector is placed and the number of the F3 -Frame in which the first Control byte of the table is placed. Each Section has its own table with Control bytes.

- Recording of the F3 -Frames on the disk
In order to record the F3 -Frames on the disk each 8-bit byte shall be represented by 14 so-called Channel bits. Each F3 -Frame is represented by a so-called Channel Frame comprising a Sync Header, Merging bits and 33 14-Channel bit bytes.

- Encoding
All 33 bytes of the F3 -Frames of each Section are 8-bit bytes. They shall be converted into 14-bit bytes. The bits of these 14-bit bytes are called Channel bits. These bytes of 14 Channel bits are characterized by the fact that between two ONEs there are at least two and at most ten ZEROs. The first byte of the first two F3 -Frames of each Section, i.e. the Control byte of these frames, is not converted according to this table but is given a specific synchronisation pattern of 14 Channel bits that is not included in the table of annex D. These two patterns shall be:

1st Frame, byte 0, called SYNC 0 : 00100000000001
2nd Frame, byte 0, called SYNC 1 : 00000000010010

The left-most Channel bit is sent first in the data stream.
- Sync Header
A Sync Header shall be the following sequence of 24 Channel bits: 100000000001000000000010

The left-most Channel bit is sent first in the data stream.

- Merging Channel bits
Merging Channel bits shall be sequences of three Channel bits set according to annex E and inserted between the bytes of 14 Channel bits as well as between the Sync Header and the adjacent bytes of 14 Channel bits.

- Channel Frame
Each F3 -Frame is converted to a Channel Frame with the following configuration.

- Sync Header : 24 Channel bits
- Merging bits : 3 Channel bits
- Control byte : 14 Channel bits
- Merging bits : 3 Channel bits

Bytes 1 to 32, each followed by Merging bits : 32 x (14+3) = 544 Channel bits

Thus, each Channel Frame representing a F 3 -Frame comprises 588 Channel bits. These Channel bits shall be recorded on the disk along a Physical Track. A ONE Channel bit shall be represented by a change of pit to land or land to pit in the reflective layer. A ZERO Channel bit shall be represented by no change in the reflective layer.

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