Appeal No. 1998-1472 Page 18
Application No. 08/427,721
As the disk 2 rotates in the direction of the
arrow, each hologram is illuminated by the beam 4
from the slit of mask 12. Sound information
corresponding to a predetermined short interval of
time equal to the passing period of time is included
as code information (for example, PCM code signals,
digital signals etc. which are well known in
themselves). That is to say, each hologram
represents an encoded signal of one or more sampling
signals at the time when the voice signals are
sampled at a predetermined period of time. A
hologram apparatus which records such sampling
signals as holograms will be explained below in
conjunction with the embodiment shown in FIG. 6.
Each holograms 1 is illuminated by the laser beam 4,
and the encoded signal 5 of the voice signal is
reproduced as a reconstructed image of the hologram.
Of course, position of the reconstruction is the
focusing position of the hologram behind the disk 2.
Since the encoded signal 5 is constructed by "on" and
"off" modulation of a light beam as will be discribed
[sic] below, it is read by means of a photodetector 6
(made up of, for example, a photodiode array). In
this case, the encoded signal 5 is condensed on the
photodetector 6 through an optical system 16. Output
signals from the photodetector 6 become input signals
to an information processor 15 (for example, a
decoding unit which is constructed of a decoder, low-
pass filters etc. as is well known). The encoded
signals are decoded by the processor 15 into vocie
[sic] signals. The voice signals are emitted by a
sound reproducing device 9 (for example, a
loudspeaker) to appeal to the ear.
Col. 3, ll. 4-53. More specifically, by reproducing holograms
1 representing encoded signals, Takeda teaches reading data.
By employing the photodetector 6 and information processor 15,
the reference teaches using an electro-optical head to read
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