Compression and expansion circuitry for a recording and playback system

DETAILED DESCRIPTION Referring to the drawings and particularly to FIGS.
1 through 3, an apparatus includes a first optional scanner 10 and a second optical scanner 12 which are adapted to scan beams of electromagnetic energy, e.
g.
light beams, across a record medium 14.
A record medium 14 is suitably a tape unreeled from reel 16, passing between capstan rollers 18, 20 and 22, 24 in the direction of the arrow, and received onto a pickup reel 26.
Capstan rollers 18 and 22 are respectively empowered by servo motors 28 and 30 (see FIG.
2), and have a contoured surface for "dishing" a record medium 14, as illustrated in FIG.
3, whereby the light beam from scanner 10 can be accurately focused upon the record medium.
The record medium should be self-developing.
There are several classes of photosensitive materials that are satisfactory, i.
e.
, dry silver, free-radical, vesicular (Kalvar), thermal destruction (melt or vaporize), and photochromic.
The dry silver and free-radical systems require a further treatment of heat if a permanent record is desired.
Hence, for these materials a heating element (not shown) is employed subsequent to recording by means of scanner 10.
The various rapid light recording media are known by those skilled in the art.
Scanner 10 suitably comprises a metal cylinder 28 journaled in bearings 31 supported in turn by an outer cylindrical body 32 which also supports motor coils 34.
Hence, the cylindrical body 28 forms the rotor of a motor such as a synchronous hysteresis type.
Upon one end of cylinder 28 is secured a head 36 which rotates and carries a plurality of objective lenses 38 around the forward periphery thereof.
As illustrated in FIG.
3, six evenly spaced objective lenses 38 may be located at the forward end of head 36 and disposed in an angular forward wall of the head for scanning across the record medium 14 as the cylinder 28 is rotated about its axis which is parallel to the direction of motion of the record medium 14.
The light for scanner 10 is provided by a laser 40 positioned axially forward of the scanner 10 and adapted for projecting a beam of light 42 substantially along the axis of the scanner through a modulator 44 to an optical tube 46 which is suitably located partially within cylinder 28