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Патент USA US2128750

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Aug. 30, 1938.
2,128,750
w. KRIEBEL
ULTRA~SHORT WAVE REEJEIVING APPARATUS
Filed Oct. 28, 1937
47
INVENTOR.
__
BY
7
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A
/
El? KRIEBEL
'
ATTOIQVEY.
Patented Aug. 30, 1938
2,128,750
UNITED STATES PATENT orncr:
2,128,750
ULTRA- SHORT WAVE RECEIVING APPA
RATUS
Walter Kriebel, Berlin, Germany, assignor to
Telei'unken Gesellschai't fiir Drahtlose Tele
graphic 111. b. 11., Berlin, Germany, a corpo
ration of Germany
Application October 28, 1937, Serial No. 171,443
Germany S eptember 2, 1936
3 Claims. (Cl. 250-271)
The present invention relates to a tube vde
ing embodiments of the invention are shown.
tector for receiving ultra-short waves. This de
tector is more sensitive than a bolometer and
exhibits above all a uniform response.
The inventive idea is as follows:
The emission source or cathode of a discharge
tube, e. g. of a diode, is directly supplied with
the high-frequency receiving current so that
heating or additional heating is effected thereby.
10 As the emission of a cathode, so long as the ap—
plied plate voltage by far exceeds the saturation
voltage, greatly depends on the heating, relatively
small variations of the receiving currents may be
made perceptible in this manner.
E. g. a heat
15 ing current variation by 1% yields an emission
variation of about 20%.
One reason why the
plate voltage must exceed saturation voltage is
to prevent space charge between the cathode and
the plate.
20
’
A relatively simple arrangement results, if a
diode is used as receiving tube and one dipole
half each is attached to the ends of the straight
cathode.
-
As the ?lament energy consumption varies for
a given resistance of the spot to be heated with
the square of the current the cathode, pref
erably, is initially heated by a constant but ad
justable, as may be required, direct current and
the received high-frequency oscillations are used
only to render an additional heating. To avoid
the high-frequency leaking off through the heat
, ing current leads, one may either design the
emissive spot to be very small so that it prac=
tically lies only in the voltage node of the dipole,
w or tune the heating current leads by means of a
metal slider which is insulated from the heating
current leads and is sliding on them. Further,
one may shape the emissive spot to an indirectly
‘ heated cathode.
In this case the heater is shaped
Therein is designated by:
,
I the plate of a directly heated diode 9; 2 and
3 a dipole joined to the terminals of the ?la
ment 4 (2 and 3 are tuned to M2 of the decimeter
wave to be received); 5 a variable resistance for
adjusting the heating current supplied by the
heating battery 6 and thereby at the same time
the emission of the ?lament 4 to the most fa
vourable value, ‘I an indicator, e. g. a head phone,
8 the plate battery. The ?lament consists of a 10
tungsten-, thoriated or oxide-coated wire. The
oxide-coated ?lament, e. g., is made of a core of
platinum or a platinum-iridium alloy to which
oxides of the alkaline earth metals, as calcium-, 15
strontium- or barium-oxide, together with var
ious admixtures are pasted, fused or sintered on.
The performance of the device is as follows:
The modulated high-frequency, which oscil
lates on the dipole together with the inserted .
?lament, varies the heating and thereby the emis
sion'of the ?lament in time with the modulating
amplitude. The emission variations produce
plate current variations in the plate circuit,
which are listened to by means of head phones
either directly or through an ampli?er,
To reduce still more the thermal inertia of
the ?lament, the ?lament 4 may be given the
shape of a platinum tube about 2p. in thickness,
which is covered with oxides, if required.
Fig. 2 shows practically the same receiving de 30
vice as Fig. 1. Like reference numerals represent
like circuit elements. Only the cathode 10 has
been varied. The preferably thin-walled emis
sive sleeve is initially heated by a heater being
situated within the sleeve. The wires of 35
the heater are running in opposite directions
and led out at‘the centre of the emissive sleeve.
In Fig. 3 an arrangement is shown in its prin
to run bi?larly within the emission layer support - ciple, adapted in particular to receive very short
and the lead-in wires are placed. exactly at the waves. To avoid losses at the seals of the dipole 40
voltage node. With extraordinary short waves it through the wall of the vessel and to be able to
may occur) that the small dipole halves intended make the radiation collecting part without the
to collect the radiation ‘lie at the greater part vessel of su?icient length, the whole arrange
,5 within the vacuum vessel or in the wall of the ' ment comprising the radiation collector and the
tube. In such case it is recommendable to make cathode, has been made equal to an odd number 45
the radiation collector equal to'an odd number of half wave lengths, e. g. 3/2)., 5/2ll etc. The
of half wave lengths, e. g. 3/2)\, and to arrange cathode II and the seals l2 and I3 are positioned
that one voltage node each lies in the centre each at one voltage node of the stationary waves
‘0 or the emissive spot and at the seals through the ' built up on the total arrangement.
50
wall of the vessel respectively; or, alternately,
In the operation of the device of the invention,
one mounts the tuned dipoles, i. e. dipole de
it will be appreciated that the extra ?lament
‘signed to have a certain length, together with the heating provided by the waves collected by the
emission source within the vacuum. vessel.
antenna gives plate current in proportion to the
In the Figs. 1 to 3 of the accompanying draw
amplitude of the extra heating current,- and hence 65
2
2,128,750
_Q.'
in proportion to the amplitude of the received
minals or the cathode of saiddischarge device,
waves. This extra plate current, varying in ac
cordance with the wave amplitude, constitutes a
an indicator coupled to the plate circuit‘ of said
discharge device, the said radiation collectors to
gether with said cathode being so arranged that
the total length is an odd multiple including unity
modulation frequency current through the head
phones.
‘
What is claimed is:
1. A tube detector comprising a space dis
charge device, radiation collectors attached to the
terminals of the cathode of said discharge device,
10 an indicator coupled to the plate' circuit of said
discharge device, the said radiation collectors to
gether with said cathode being so arranged that
the total length amounts to 3/2x and 'one voltage
node each occurs at the seals through the wall
15 of the device and at the centre of said cathode
where A is the length of the collected wave.
2. A tube detector comprising a space discharge ‘
device, radiation collectors attached to the ter
of half the length of the collected wave.
3. A tube detector comprising a space discharge
device, radiation collectors attached to the ter
minals of the cathode of said discharge device,
an indicator coupled to the plate circuit of said
' discharge device, the said radiation collectors to
gether with said‘ cathode being so arranged that
the total length is an odd multiple including
unity of half the length of the collected wave,
and a voltage node occurs at the center of said
cathode.
WALTER KRIEBEL.
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