Evening star., 1923-03-04
PHOTO BROADCASTINC
SEEMS EARLY REALITY
Fans Looking Forward to Time When
They Can See as Well as Hear
Worldwide Activities.

, 1t is. therefore. very much superior in
this respect, as we'll as in other re-
spects.
TrRnsmission Over Wires.
The American system is capable
Of transmitting the equivalents of
pictures over land wires, as well as
through space by radio, and instant
ly reproducing accurate likenesses at
distance.
1t can be associated with the exist
ing types of high-power radio sets
now in daily use for transocean and
transcontinental telegraphy for the
transmission of straight black and
white contrast images, such as maps,
sketches, handwritten letters, orders.
signatures, etc, which show sharp diff
ferences and do not require shading.
For images which require shading.
| especially delicate shading effects.
the system will probably have to be
associated with wired wireless" for
land wire work and with tube trans
mitters for radio work. These sys-
TENS of communication are not as yet
in general use for regular long dis
tance work. but their advent in the
long distance communication field is
not far distant.
The American system will transmit
the exact equivalents Of any object
which can be made transparent. such
as lar tern slides and Photographic
films, and of which the image can be
suitably cast on a certain part of the
transmitting apparatus. Opaque OBJ
jects which cannot be made trans
parent by light waves. such as hand
writing on post card or sneet OF
paper. a cardboard photograph. map,
ship. landscape. etc, can be transmitted
by illuminating the object by the re-
flect-Scope method SO that the lense
produces an image in the proper part of
the transmitting apparatus.
The system Of transmission also
makes 1t possible to turn the lense
of the transmitter directly on the de-
sired object. such. for example as a
conhagration, volcanic eruption. a
landscape. n land or sea battle as
viewed from an airplane lowering IN
| the vicinity. and Immediately trans
NIT to a distance an accurate picture
of the same.
The picture equivalents as carried
through space with lightning like
speed are in the form of modulated
ether or radio waves, the modulatlon
of the waves corresponding to the
differing shades of the object whose
image has been cast on the tense at
the transmitting station.
Wave Impulses Picked Up.
The oncoming picture wave i'm
pulses are picked out Of the air at
the same manner as ordinary radio
signals. after which they are led into
sound box containing a telephone
receiver. a minute mirror capable or
rapid vibration, and certain record
ing camera mocha aniSm. A beam of
light is projected into the sound box
through a small aperture so that 1t
strikes the mirror and is reflected on
the camera.
The sound waves set up in the
sound box by the incoming picture
wave impulses in turn causes the
miniature mirror to vibrate in such
manner that light waves correspond
ing in intensity to the incoming
waves, which in turn correspond to
the degree OF shading of the image
being transmitted, are impinged on
the camera with the result that the
corresponding image is reproduced on
the film.
The apparatus is so arranged that
light waves are reflected on the pho
walls when the mirror Is vibrating in
response to the sound waves set up
by the incoming picture waves
A picture three and one-half inches
square can be transmitted and receiv-
ed in an interval of time Of approx
mately two minutes in the present
state of development of the trans
mitting and receiving. apparatus.
The power of the transmitting sta
tion required for radio Photographic
work need not be appreciably greater
than that required for ordinary radio
signaling over corresponding dis
tances The equivalent is not unduly
complicated either for. transmitting
or recording. and the apparatus can
be readily operated by the average
radio personnel after they have been
properly instructed ...