US2077290A

US2077290A - Method of and arrangement for receiving short waves

Info

Publication number: US2077290A
Application number: US74441A
Authority: US
Inventors: Ardenne Manfred Von
Original assignee: Individual
Current assignee: Individual
Priority date: 1933-02-15
Filing date: 1936-04-15
Publication date: 1937-04-13
Anticipated expiration: 1954-04-13
Also published as: FR768728A; GB432728A

Description

April 13, 1937- M. VON ARDENNE 2,077,290

METHOD OF AND ARRANGEMENT FOR RECEIVING SHORT WAVES Original Filed Feb. 5. 1934 MMQM Patented Apr. 13, 1937 v UNITED STATES METHOD OF AND ARRANGEMENT FOR RECEIVING SHORT WAVES Manfred von Ardenne, BierlimiGermany V Original application February 5, 1934, Serial No. 709,707. Divided and this application April 15,

o 1936, S3erial No. '74,441. In Germany February The present invention relates to an electronic tube for rectifying short waves and is a division of application, Serial No. 709,707, filed February 5, 1934.

the same control potential when normal radio waves are rectified.

By careful investigation of the frequency dependency of the efiiciency of the rectifier the applicant has been able to ascertain the reasons for the low efiiciency not occurring in the normal radio frequency range, and to find means for remedying the same.

Experiments of this nature may be conducted in such fashion that one and the same highfrequency amplitude is conducted to a tube rectifying connection system at a frequency varied between i=3 meters and 200 meters, the potential rectifying eifect is measured in the anode circuit. By such measurements the applicant has found that the rectification of short waves is considerably better if relatively powerful ourrents are efiected in the rectifier circuits. .Ac-

cording to the invention, this is effected by employing small resistances in the anode circuit.

Experiments have provided the following results:

In the range of the frequencies below a wave length of 30 meters the sensitiveness decreases in the case of anode bend rectification with the use of grid leakage resistances in the usual order of 10 ohms and reaches the relatively lowest value at 7 meters. Also in the case of anode bend rectification with high anode resistances of approximately 500,000 ohms there is a decrease in the sensitiveness in the case of waves below approximately 20 meters. Now a considerably better effect may be obtained in accordance with the invention by operating in the case of anode bend rectification with anode resistances which are considerably smaller than those employed with good results for normal frequency.

The electrons which in the case of anode bend rectification with high anode resistances form the anode current possess speeds which are usually very low, the control potential possessing a value in the order of approximately 1 volt. The

electrons do not assume higher speeds until the electrons have passed the grid, i. e. at a time when control has already taken place. As long as the electron speeds are so small, the time in which an electron is passing from cathode to anode is such that the same is greater, or may 5 be greater, than the period, for example, of a 7-meter oscillation. From the influence exerted by the duration of passage of the electrons, which cannot be ignored in rectification, there results. the frequency dependency of the rectification in 0 the frequency range above stated.

After having found out the reasons for this frequency dependency in accordance with the invention for improving the efficiency of the anode-bend rectification for short waves there 15 is used a relatively small anode resistance in the order of 10 ohms, which causes the full anode I potential to be applied to the anode practically continuously; further, tubes having a relatively small amplifying factor =10 are used. in this 20 connection the resting or working point is transferred as far as possible near to or in the upper bend in the characteristic of the anode current. The object of the arrangement according to the invention is to perform the control in such fash- 25 ion by the high-frequency potential to be rectified that electrons having as far as possible a high speed are covered by the control, and that the control takes place in a narrowly confined space surrounding the grid. I 0

When employing connection systems having resistances with the value and arrangement as set forth in accordance with the invention it is possible to produce receivers for short waves, and more particularly waves of less than 10 meters 35 (preferably for television purposes), which have an adequate sensitiveness, even without inter mediate frequency.

In the drawing there is shown by way of an example a form of embodiment of receiving and 40 rectifying systems for anode-band rectification, the connecting elements in the working circuits having the values according to the invention. The single parts are the rectifier tube l with the cathode 2, the grid 3 and the anode 4. 45

Between the grid and the cathode there is provided the oscillatory circuit 5, which comprises the self-inductance 6 and the variable capacity 1.

In the outer anode circuit there is connected 50 a resistance II which, in accordance with the invention, is in the order of 10 ohms. Coupling is performed through the medium of a condenser I 2. To accomplish a transfer of the working point to the upper bend of the characteristic 55 10 fication factor, the anode potential being sulficient to make the time the electrons take to pass the distance between the electrodes shorter than a period of the high frequency to be rectified.

2. In a tube for rectifying short waves, more 15 particularly for waves of less than 10 meters,

using anode bend rectificatioma cathodaa grid and an anode, said anode connected to a source of high positive potential over a relatively small anode resistance, said tube having an amplification factor smaller than 10, the anode potential being suflicient to make the time electrons'take to pass the distance between the electrodes shorter than a period of the high frequency to be rectified.

3. In a tube for rectifying short waves, more particularly for waves of less than 10 meters, using anode bend rectification, a cathode, a grid and an anode, said anode connected to a source of high positive potential over a relatively small anode resistance, said tube having a small amplification factonthe anode potential being sufficient to make the time the electrons take to pass the distance between the electrodes shorter than a period of the high frequency to be rectified, a high positive grid bias suflicient to obtain a working-point in the upper end of the plate currentgrid voltage characteristic.

MANFRED VON ARDENNE.