US2090951A

US2090951A - Relaxation oscillation generator

Info

Publication number: US2090951A
Application number: US689760A
Authority: US
Inventors: Schlesinger Kurt
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-09-28
Filing date: 1933-09-16
Publication date: 1937-08-24
Anticipated expiration: 1954-08-24
Also published as: GB425685A; FR761114A; DE716371C

Description

K. SCHLElNGER RELAXATION OSCILLATION GENERATOR Filed Sept. 16, 1933 HIGH PASS FIL TER i F. AMPL/ Hm I E 313- PHASE SHIFTER 45 over the resistance 4.

Patented Aug. 24, 1937 UNITED STATES PATENT OFFICE Kurt Schlesinger, Berlin, Germany Application September 16, 1933, Serial No. 689,760 In Germany September 27, 1932 6 Claims.-

When employing glow lamps, and more particularly gas-filled glow lamps, in the known relaxation oscillation generators, the first part of the discharge takes place so rapidly that the return line on the television screen is not visible.

On the other hand the discharge, on the final part of the discharge curve, shortly before extinguishing commences to take place, proceeds relatively slowly. This part of the return line is accordingly visible on the screen of the Braun tube.

The subject matter of the invention is a meth- 0d of and also an arrangement for enabling this disadvantage to be avoided. The invention will be best understood with reference to the accompanying drawing, in which Fig. 1 shows the scanned picture area with the course of the return line, while Figs. 2 and 3 show exemplary embodiments of the invention for removing the visible portion of the return line from the picture area.

In Fig. 1 the upper part of the return line commences with a sharp bend at I and is completely invisible up to the point 2. The lower part of the return line owing to the slower wandering velocity over the picture screen is thickened, and is visible in a disturbing fashion in the image.

According to the invention, the anode of the glow lamp 3, after commencement of the ignimatically in Fig. 2.

In this figure, 3 is a glow lamp, which is preferably operated with a grid of suitable constant, negative bias, and 5 a condenser, which is charged in the known fashion by the battery 6 To the charging circuit there is connected a power amplifier l with wattless input. In the anode lead of the amplifier 1 there is provided a retarding member, which consists, for example, of the resistance 8 and the condenser 9, and the primary winding of a step down high-frequency transformer Hi. The secondary winding of this transformer, which winding is preferably constructed with very low highfrequency impedance, and which transformer may be bridged by a small condenser II, is connected in series with the discharge circuit. The operation of the arrangement is as follows:

Whereas upon the charging of the tilting condenser 5 the discharge tube 3 is .blocked by its control grid in respect of all anode potentials occurring, and the high-frequency transformer [0, therefore, is also ineffective, upon the discharge there is provided in the anode circuit of the connected amplifier tube 1 a high-frequency impulse, which is transmitted very well by the selective transformer. In the retarding

member

8, 8 there is adjusted a delay of such extent as corresponds with the invisible branch of the return line I, 2 in Fig. 1. It is not until this period has elapsed that the high-frequency impulse wave reaches the primary winding of IO, and produces in the secondary winding a potential impulse, the value of which is at least equal to the particular relaxation condenser potential at the moment, andpreferably is greater than the remaining potential, and the phase of which for the first moment of the condenser potential is oppositely directed. With suitable selection of this counter-potential it may readily be accomplished that the duration of the potential-less condition at the anode of the glow tube suffices for a complete de-ionization of the are. The sub-- sequent disposal of the secondary winding of the transformer is accordingly unimportant, and possible oscillation effects thereof are without harm, as the discharge tube, owing to the occurrence of the grid effect, is again blocked for all anode potentials.

An additional form of embodiment of the idea according to the invention is illustrated diagrammatically in Fig. 3. The counter-impulse which blocks the discharge is not derived by reaction from the discharge operation itself, but from the synchronization potential, for example a signal potential. This potential is indicated in Fig. 3 by the generator 12. For television purposes this potential is necessary in any case for the operation, and is supplied by the television receiving apparatus to the relaxation oscillation system. Alternatively, this potential may also be taken from the supply potential at the terminals of the condenser 5. The potential I2 is first conducted over a phase shifter l 3, which produces its correct chronological relation to the discharge phase. It then passes to a suitable amplifier l5. This amplifier must be in a position to produce at the impedance resistance 16 connected in the discharge circuit, for example a small coil, a potential of small amount, which is sufficient to make the anode potential at the glow discharge tube 3 for a suflicient length of time equal to zero or negative. The form of the curve after this point is unimportant. After the amplifier 15 there is preferably connected in series a highpass filter ll, the reactance of which for the useful frequency of the relaxation oscillation is extremely high.

Naturally, it is quite possible, without departing from the idea according to the invention, also to set forth other circuits for carrying out the method in the invention, which systems permit of performance of the method in simple fashion;

In the method according to the invention the charging condenser is on each occasion discharged, not down to zero, but merely. down to the potential corresponding with the point 2 of the return line. This loss of potential, however, may be counter-balanced without difficulty by The method increasing the working potential. according to the invention enables television images to be produced, which are completely free of a visible return line.

I claim:

1. A generator for producing relaxation oscillations comprising a unidirectional source of potential, a charging condenser and a charging resistance in series, a glow discharge device across said charging condenser, an amplifier means hav ing input and output, said input being connected across said device and means connected to said output for applying a potential across said condenser and device counter-acting the condenser potential during a part of the discharge period of said condenser for preventing a complete discharge of said condenser by said glow discharge device.

2. A generator for producing relaxation oscillations comprising a unidirectional source of potential, a charging condenser and a charging resistance in series, a glow discharge device across said charging condenser, an amplifier having input and output, said input being connected across said device and means connected in said output for feeding back a potential across said condenser and device during a part of the discharge period of said condenser for preventing a complete discharge of said condenser by said glow discharge device.

3. A generator for producing relaxation oscillations comprising a unidirectional source of potential, a charging condenser and a charging resistance in series, a glow discharge device across said charging condenser, a high frequency stepdown transformer, the secondary thereof being connected in series with said glow discharge device across. said condenser, an amplifier stage having input and output circuits, the input circuit being connected across said '-device,'the primary of said transformer being connected'in the output circuit of said amplifier stageand' phaseretarding means being connected in said output circuit. I

4. A generator for producing relaxation oscillations comprising a unidirectional source of potential, a charging condenser and a charging resistance in series, a glow discharge device across said charging condenser, a high frequency step-down transformer, the secondary thereof being connected in series with said glow discharge device across said condenser, an amplifier stage having input and output circuits, the input circuit being connected across said device, the primary of said transformer being connected in 'the output circuit of said amplifier stage and phase-retarding means comprising a second resistor and a second condenser connected in said anode circuit, said high frequency step-down transformer having a proportion of windings and said phase retarding means being so dimensioned as to generate a potential counter-acting the condenser potential at least to full extent during a part of the discharge period of said charging condenser for, preventing complete discharge of said condenser by said discharge device during said part of the discharge period.

5. A generator for producing relaxation 'oscillations comprising a unidirectional source of potential, a charging condenser and a charging resistance in series, a grid controlled glow discharge device having cathode and anode elec trodes, said electrodes being connected across said charging condenser, means for applying a synchronizing potential to the grid of said discharge device, means for generating an additional potential controller by said synchronizing potential, means for applying said additional potential to counter-act the condenser potential during a part of the discharge period of said condenser for preventing a complete discharge of said condenser by said glow discharge device.

6. A generator for producing relaxation oscillations comprising a unidirectional source of potential, a charging condenser and a charging resistance in series, a grid controlled glow discharge device having cathode and anode electrodes, said electrodes being connected across said condenser, an amplifier having input and output, a phase shifter, means for applying a synchronizing potential to the grid of said discharge device and to the input of said amplifier through said phase shifter, an impedance connected in series with the electrodes of said"dis-.

charge device and said charging condenser; 'a high frequency filter, said impedance and filter being connected in series in the output circuit of said amplifier, said impedance Withholding said synchronizing frequency from said con-denser, thus generating an additional potential derived from said synchronizing potential, said additional potential counter-acting the condenser potential during a part of the discharge period of said condenser for preventing a complete discharge of said condenser by said glow discharge device.

KURT SCHLESINGER.