US1927425A - Electric frequency-transforming device - Google Patents

Description

Sept. 19, 1933.

J. VAN DER MARK El AL 1,927,425 ELECTRIC FREQUENCY TRANSFORMING DEVICE Original Filed May 29 .1928

5) THE/R ATTORNEY (9:1! 44 Patented Sept. 19, 1933 UNITED STATES PATENT OFFICE ELECTRIC FREQUENCY -TR.AN SFORMING DEVICE Application May 29, 1928, Serial No. 281,468, and-in Great Britain June 14, 1927. Renewed January 30, 1932 11 Claims.

The present invention is concerned with a frequency-transformer of the stationary type and has for its object to provide an apparatus of this class which, under the influence of incoming primary electric oscillations, is adapted to generate secondary oscillations at a frequency which will be lower than thefrequency of the incoming oscillations.

The object of the invention is to provide means by which the ratio between the frequency of the primary and that of the secondary oscillations may be readily adjusted.

The invention will be more fully described with the aid of the accompanying drawing. Figure 1 shows graphically how the primary oscillations are de-multipled. Figure 2 is a schematic showing of the device according to the invention. Figure 3 shows graphically the frequency of the relaxation oscillations plotted against the natural frequency of the primary oscillations.

According to this invention, the primary oscillations control the vibrations in a circuit containing a condenser and a resistance, either of which or both of which can be made variable, and a gap across which the condenser may discharge itself when the potential difference between its electrodes has reached a predetermined value owing to its being charged through the said resistance by a battery or other suitable constant potential source. Oscillations set up in this way, which may be called relaxation oscillations", will have a time period which is a linear function of the product of the capacity C of the said condenser and of the value R of the said ohmic resistance, as is well known in the art. (See e. g. Philosophical Magazine, November, 1926.)

When the alternating potential of the primary oscillations of a frequency W0 is superimposed upon the direct current voltage between the plates of the condenser, the latter will be charged in the way graphically shown in Figure 1 of the drawing accompanying the specification, in which the tension V between its plates is plotted as a function of the time. As soon as V attains the value V0, the condenser will suddenly discharge across the above-said gap, which, for instance, may be the interelectrodic space of a glow discharge lamp, whereupon the condenser will again be charged in the manner described and soon. From the diagram of Figure 1, it will whole submultiple of W0.

be clear that each charging period will correspond with a plurality of primary oscillations, say 11. full waves, which makes the frequency W of the relaxation oscillation equal to Since n will depend upon the steepness of the curve a in Figure l which shows the unidirectional potential between the condenser plates as a function of time; and since said steepness may be varied at will by varying either or both of the values- R and C, it will be obvious that W may also be given practically any desired value being a The consecutive discharges of the condenser will occur at such points of the combined voltage curve as are in a phase with each other with regard to the primary oscillations which means that there will be always a whole number of full primary oscillations between each two discharges of the condenser. Consequently, when the steep- I ness, of the curve a is varied gradually, the value of the resulting frequency W will vary discontinuously. It is thus possible to obtain relaxation oscillations, the frequency of which amounts to /2, A, A etc. of the frequency of the primary source.

Figure 2 is a diagram of connections showing an embodiment of the invention. A source 1 of an alternating electromotive force of a suitable amplitude is connected in series with a glow discharge lamp 2 and a variable condenser 3. In parallel to the condenser 3 a battery 4 and a resistance 5 are put in series with each other. Condenser 3 is charged by battery 4. through resistance 5, the alternating potential of the source 1 being superimposed upon the direct current potential between the plates of condenser 3. The latter will periodically discharge itself through the glowlamp 2.

When the capacity of the condenser 3 is varied gradually, say from its minimum to its maximum value, the frequency of the relaxation oscillations which initially amounted to say A WO, will remain unchanged for some time and then when the natural relaxation-frequency of the R. C circuit is closer to Wo than to M WO will suddenly fall to /;;W., and so on. This is graphically shown in Figure 3, where the frequency W of the relaxation oscillations is plotted against the natural frequency We of the primary oscillations.

It will be obvious that the invention is not confined to the use of a glowlamp for the gap across which the condenser may discharge itself, but that other devices, such as, for instance, electron discharge tubes of various design may be used instead, without departing from the invention.

What we claim is:

1. A circuit arrangement for de-multiplying electrical oscillations, comprising-a source of primary oscillations in series with a path of discharge, a condenser, a resistance, and a source of direct current, the resistance and the source of direct current being connected in series with the source of primary oscillations and the path of discharge, and the condenser being connected in parallel across the resistance and the source of direct current.

2. A circuit arrangement for producing whole sub-multiples of electrical oscillations comprising a source of oscillations in series with a path of discharge, a condenser, an impedance, and a source of uni-directional current, the impedance and the source of direct current being connected in series with the source of oscillations and the path of discharge, and the condenser being connected in parallel across the impedance and the source of direct current, said condenser being adapted to periodically discharge across said path to produce a frequency lower than the frequency of said source of oscillations.

3. A circuit arrangement for producing whole sub-multiples of electrical oscillations comprising a path of discharge, a condenser, an impedance, said condenser and said impedance being connected in parallel across said path of discharge, a source of primary oscillations and a source of unidirectional current associated with said condenser, both said sources being arranged to impress currents simultaneously upon said condenser, said condenser being adapted to periodically discharge across said path at predetermined intervals to produce a current of a frequency lower than the frequency of said source of primary oscillations. a

4. A circuit arrangement for' demultiplying electrical oscillations comprising a glow discharge device, a circuit comprising a reactance, an impedance and a source of uni-directional potential connected with said glow discharge device, and a source of primary oscillations connected to said circuit and said' device, both said sources being arranged to act simultaneously upon said reactance to cause said arrangement to oscillate at discrete frequencies determined by whole submultiples of the applied frequency.

5. A' circuit arrangement for demultiplying electrical oscillations comprising a space discharge device, a source of potential in series therewith, a series combination of a variable condenser and a resistance connected across said source of potential, and a source of primary oscillations coupled to said device and said series combination, both said sources being arranged to act simultaneously upon said device and condenser to produce oscillations of a frequency lower than the frequency of said source of primary oscillations.

6. A circuit arrangement for sub-dividing electrical oscillations comprising a source of primary oscillations, a source of uni-directional current,

a space discharge and a resistance element connected in series one with respect to the other and forming together a closed electrical circuit, and a condenser upon which the currentsfrom both said sources are directly impressed connected in parallel with a portion of said circuit to divide the circuit into two parts each including one source so that the source of primary oscillations is adapted to alter the natural charging period of the condenser to vary thereby the normal oscillation frequency of the system.

7. A frequency demultiplication system comprising a relaxation oscillator circuit including as a part thereof a gaseous discharge device, a source of direct current and an energy storing element to control the time period of operation thereof, and a source of applied oscillations of a frequency other than the normal oscillation frequency of ,the system connected with the oscillator circuit so as to act simultaneously with the direct current upon the storing element and thereby to cause the element to discharge through the discharge device periodically at a frequency which is a whole sub-multiple of the applied frequency, said discharge frequency being equal to 1 where W0 is equal to the frequency of the applied oscillations and N is equal to any desired number of full waves.

8. An oscillation circuit comprising a series combination of a discharge device, an impedance and a source of unidirectional current and 9. capacity element connected in parallel with a portion of the series combination so as to control in accordance with the capacity value thereof the natural oscillation frequency of the combination, and. means for supplying in series with the discharge device an alternating current voltage so as to vary thereby the natural oscillation'frequency of the system.

9. An electrical circuit comprising in combination a relaxation oscillator circuit having a predetermined natural oscillation frequency, and means to impress alternating currents upon the oscillator circuit of a frequency other than the normal oscillation frequency to cause the oscillator circuit to produce oscillations at a frequency other than its normal frequency.

10. An electrical circuit comprising in comblnation a relaxation glow discharge oscillator circuit having a predetermined natural oscillation frequency, and means to impress alternating currents upon the glow discharge oscillator circuit of a frequency other than the normal oscillation frequency to cause the oscillator circuit to produce oscillations at a frequency other than its normal frequency.

11. In an electrical generator system, a relaxation oscillator including a space discharge ele- .ment, a source of unidirectional current and an impedance element serially connected and a capacity element to control the natural oscillation frequency connected in parallel with a portion of the series combination, and means for impressing upon the series combination alternating current voltages at a frequency other than the normal oscillation frequency of the relaxation oscillator so as to cause the frequency of the generated oscillations to vary under the control of the supplied alternating currents.

JAN VAN DER MARK.

BAL'I'HAZAR van on POL.

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