Evening star., 1923-05-27
AmpIifier Tube Functions
In Broadcasting Explained
Likened to Miniature Tras,smitter Within,
Influence il, Long-Distance Signals.

employ a single detector tube in place
of the most sensitive crystal
When we add radio frequency am
plifier TUBES to our receiving equip
ment we transplant so to speak, the
distant broadcast transmitter in
miniature form directly in our re-.
ceiver.
AS a radio frequency amplifier the
tube Stimulates a relay" or way sta
ton" for distant transmitting sta
, tions.
Sensitivencss of Tube n Factor.
The sensitiveness of the tube as
radio frequency ampllfier is equaled
only by it's marvellous versatility. 1t
would seem to be only necessary to
endow 1t with reason to make 1t
human.
1t suffers the distant broadcast sta
tons voice. music and other electro
magnetic sound equivalents (although
they may be soreXtremely weak when
impressed upon it through the an
tenna and receiver circuits as to be
barely perceptible even to itSelD to
mold its own comparatively vigorous
| energy into their corresponding fire.
quency. form, and qualities. 1t
STRENGTHENS these equivalents enor-
moualy; perhaps 1000 times, possibly
| 10000 time or more.
1t actually cl Gates human speech.
for example. out of something that
was incapable OF producing human
speech.
When used as a radio frequency
amplificl ii will accommodate and
strengthen incoming signal oscilla-
tfons so extremely weak that even
our marvelously sensitive detector
tube will not accommodate and rec
ttfy them into audio frequency pulses.
This is the principal reason for
utilizing radio frequency amplifers-
to increase the strength of weak in
coming radio frequency oscillations
sufficiently to cause the detector tubes
own energy in turn to accommodate
them for rectification purposes.
When we employ radio frequency
amplifiers in our receivers, therefore,
the tubes circuits are always asso-
ctated with the ->--:~er circuits in
such a way that the incoming signal
oscillations are impressed on the in
put circuit of the tube. The radio
frequency amplifer accommodates
them, strengthens them. and delivers
them in the identical form in which
received through it's output circuit.
As many as three radio frequency
amplifiers may be used to advantage
in receivers. If three are used the
incoming signal oscillations are many
times as strong by the time they
reach the detector tube as they would
be If only one were used
Not Producer Of Sound Waves
Radio frequency oscillations are
lelectro-magnetic undulatory move
mentS in the ether. Dr reversaIs of
current flow in electrical circuits. of
an extremely high order. 1t is be-
lieved they are incapable of produc-
ing sound waves, or If they do the
waves are of such high pitch as
to be inaudible to thu human ear.
broadcast station transmitting on
a wave length of 40 meters. for ex-
ample, creates ether waves the fire.
quency of which lre 100000 cycles
per second. TheI corresponding os-
cillatory currents in our receiver and
radio frequency amplfier tube cir
cults before they reach the detector
and likewise reverse their direction
10000 times per second.
The range of frequencies which may
produce sound waves audible to the
sounds of extremely high audible
pitch to about fifteen cycles for
sounds of extremely low pitch.
The function of the detector is to
rectify the oscillatory or alternating
currents of these extremely high fire.
quencies to direct current pulses of
frequencies corresponding to audible
sounds of the general order of 1000
cycles.
Effect of Frequency Amplifers,
When we employ audio frequency
ampliherS with our tube detector
either in conjunction with or without
the radio frequency ampIifiers. we
transplant, SO to speak, the distant
broadcast performers In our receivers
In much the same manner that we
transplant the distant broadcasting
tranSmitter when we employ radio
frequency amplifiers.
These amplifiers function to in
crease the strength of the rectified
pulses of audible frequency pulses of
voice and music equivalent to cur
rents in much the same manner that
the radio frequency amplifiers in
crease the strength of the radio fire.
Quency oscillations.
The basic functioning of all three
electrode tubes is identically the
same. The electrical circuits asso-
ctated with the tubes determines
whether they will act as radio fire.
quency amplifiers, detectors, or audio
frequency amplifers
fCopyrighted, 1923 a1st Century Press1