Evening star. [volume] (Washington, D.C.) 1854-1972, 1926-01-08
FIFTEEN MINUTES OF
RADIO EACH DAY
BY JOSEPH CALCATERRA.
All Rights Reserved. Repro. Prohibited.
The Meditation of the Carrier Wave.
Part l.

1t Is difficult for some fans to under
stand the action that takes place
when a voice wave Is superimpoSed
on a ieh-frequency radio wave to
produce the radio wave that goes out
into space to affect the millions of
receivers that Will in turn strip the
wave of its carrier and reproduce the
voice wave alone.
You know, of course, that the
ordinary voice wave cannot be trans
mitted through space. The only type
of wave that can be used effectively
for that purpose must be of a high
frequency. The gh-frequency wave.
however, is useless in itself II it does
not carry the variations that will re-
produce sound in the phones of the
receiver.
Combine Waves.
The logical conclusion, then, is to
combine the two, the voice wave and
the carrier wave. Perhaps the
simplest way of explaining the action
Is TO liken 1t to "A courier and his
horse. The horse can travel over
great distances without much trouble.
but 1t Is not gifted with the ability
to talk or deliver messages. y man
can travel over short distances, but
he has the ability to carry messages.
voice waves can be used To transmit
messages without wires over com
paratively short distances, but they
cannot be made to carry them over
great distances. The MESA carry
ing properties of voice waves can
be likened to the man and the dis
lance covering properties of the high
frequency waves can be nkened to
he horse. The ideal arrangement in
hot DC - I. H.,
two: the man astride the horse which
carries him to his destination in one
case and the voice wave superimposed
on the carrier or high-frequency wave
in the other.
Meditation Explained.
Meditation is the process of molding
the high-frequency carrier wave to
the outline of the voice wave so that
the highfrequency wave goes through
space with the variations of the voice
wave.
The resultant wave when received
at the receiving station is not a
smooth voice wave, as is the case
when voice currents are transmitted
over wires without the aid of high
frequency currents, but to all prac-
teal purposes the difference between
the smooth voice waves and the
slightly Chopped up voice wave re-
sultinS from stripping the carrier
wave of its superimposed voice wave
is so slight as to be negligible
Similar to Movies.
A somewhat similar action takes
place in projecting motion pictures on
the screen. Most people know that
in moving picture every movement
Is pictured on the film as a series of
progressive positions of the move
ment. In other words every move.
ment is broken up into a number of
different positions of the member that
is making the movement
When each of these positions Is
projected in quick succession on the
screen by the moving picture pro-
jector the effect produced is that Of
a continuous motion because the eye
is not quick enough to follow each
separate motion, but blends the
separate. individual pictures into a
smooth continuous movement.
Detailed explanations OF the molding
action of the voice waves on the car
rier waves will be given in tomorrow's
article