US2170252A

US2170252A - Transformation of relaxation oscillations

Info

Publication number: US2170252A
Application number: US152949A
Authority: US
Inventors: Schlesinger Kurt
Original assignee: Loewe Opta GmbH
Current assignee: Loewe Opta GmbH
Priority date: 1936-07-16
Filing date: 1937-07-10
Publication date: 1939-08-22
Anticipated expiration: 1956-08-22
Also published as: BE422643A; GB498687A; FR48645E

Description

1939. K. SCHLESINGER 2,170,252

TRANSFORMATION OF RELAXATION OSCILLATIONS Filed July 10, 1937 2 Sheets-Sheet l //7 venzor:

Aug. 22, 1939- K. SCHLESINGER 2,170,252

TRANSFORMATION OF RELAXATION OSCILLATIONS Filed July 10, 1937 2 Sheets-Sheet 2 //7 venfor:

Patented Aug. 22, 1939 UNITED STATES TRANSFORMATION OF RELAXATION OSCILLATION S Kurt Schlesinger, Berlin, Germany, assignor to Radioaktiengesellschaft D. S. Loewe, Berlin- Steglitz, Germany Application July 10, 1937, Serial No. 152,949

In Germany 6 Claims.

The use of transformers for coupling purposes between an amplifying tube, the grid of which is excited by relaxation oscillations, and the defiecting plates of a cathode ray tube has already formed subject matter of the earlier applications of the applicant Serial Nos. 106,021 (now Patent 2,147,559) and 131,689. In the first place it was recognised as primary condition relative to the transformer that the width of its frequency band must have a range which is governed by the number of relaxation oscillations per second as lower limit and by the desired duration of the return as upper limit. Following this it was recognised that even a transformer of this nature is only capable of providing a linear deflection if the same constitutes substantially no load on the connected amplifying tube. This condition is only capable of being fulfilled by tubes having a small inner resistance, i. e. by three-pole tubes,

having a low-ohmic anode resistance shunting the transformer.

Even if these measures are adopted the image area appearing on the screen is as a rule not satisfactorily rectilinear. Additional fine correc- 25 tions are still required, which amount in substance to an integration or differentiation of the potential curve reaching the primary terminals of the transformer.

In the present application connection systems 30 are set forth by means of which it is possible to correct the deflecting potential, i. e. to make the same linear.

In-the drawings, Figs. 1 to 4 show an arrangement according to the invention, consisting of 35 relaxation generator followed by an amplifier and a step-up transformer and different means for effecting rectilinear deflecting potential.

Fig. 1 shows these means comprising a variable anode resistance of the amplifier,

40 Fig. 2 shows these means comprising an integration circuit consisting of a parallel connection of a condenser and a resistance in series to said anode resistance,

Fig.3 shows these means comprising the said 45 integration circuit according to the Fig. 2 cmployed at the same time for steadying the anode potential of said amplifier,

Fig. 4 shows these means comprising a variable resistance in series to the primary winding of said step-up transformer, and

Fig. 5 shows a suitable arrangement of the said transformer.

In Fig. 1 there is shown an operating tube I, with the grid of which there is connected 2. condenser 3, which is charged in linear fashion by way of the resistance 2 and is discharged in the known fashion upon each image change by means of a discharge tube 4. According to the invention the condition that the transformer is practically no load for the tube is fulfilled by a regulable July 16, 1936 anode resistance 5, which is traversed by the anode current from the battery l3, Whilst the primary winding la of the transformer is blocked against direct current by means of a condenser 8. The coils of the secondary winding lb are connected to the

deflecting plates

13a, 13b of the cathode ray tube, its middle point to the anode 12. By using a small anode resistance 5 the condition may be fulfilled that the inner resistance of the generator, i. e., the parallel connection of tube I and resistance 5, be smaller than the input resistance of the transformer. In practice, however, it is found that even with the best balancing of 5 there occurs a descent of the rectilinear curve due to the ohmic losses in the transformer. It has already been set forth in said earlier application Ser. No. 106,021 that a remedy against this is possible by integrating the linear relaxation potential and by furnishing the transformer with a superposition of the integrated and the linear relaxation potential. The integration is performed in principle by condenser charging. In the case of the last mentioned application this charging is performed in the grid circuit. There then occurs the difiiculty, however, that the two condensers cannot be discharged simultaneously by one discharge tube, and there occurs a slowing down of the return curve.

According to the invention, the integration is performed according to Fig. 2 in the anode circuit of the tube I. For this purpose a circuit consisting of a condenser. shunted by a resistance 6 is connected in series to the anode resistance 5. The time constant of the circuit consisting of the resistance 6 and the condenser II Resistance 5:5,000 ohms,

' Resistance 6:5,000 ohms,

Condenser 11:4 mf., Condenser 8:10 mf., Winding 7a=4,000 turns x 20 mm. Transformation ratio=1:4 to 1:6.

On the other hand also a correction in the opposite sense may be necessary. This condition occurs in the line relaxation oscillator, in' which the steadying elements (like resistance 6 and condensor II in Fig. 3) perform an integration and the resistance,.owing to the smaller input on iron core negative bias of thetube I.

resistance of the transformer, is generally speaking lower than. in the case of the image relaxation oscillator. In this case, in accordance with the invention, correction may be performed vby means of a variable resistance N] (Fig. 4) in series to the primary la of the transformer. The practical values in the case of this connection" system were as follows:

Resistance 5: 3,000 ohms, Resistance 8:0.1 mf.,

Resistance 10:0 to 5,000-ohms with idealcordeflection 7,0 0

An integral correction may also be adjusted in accordance with the invention by a stronger If the relaxation curve is. integrated according to it, there results a parabola in proportion to 15 This corresponds to a tube characteristic with an increasing steepness. As well known, this may be adjusted by adjusting the amplifying tube in the lower bend.

It is known that the charging of a condenser by way of a resistance is only linear as long as the charge is a small part of the existing charging potential. If the charging potential is better utilized, the charging curve bends a little down. This means a correction in the reverse direction to that capable of being attained with the tube bias. By simultaneous use of both corrections in the circuit of the discharge tube of the relaxation generator and in the amplifying tube the two corrections again partially compensate each other, the advantage being obtained of very good utilisation of the existing battery potential. Practical experiment will show which of the stated correcting measures according to the invention require to be employed in each individual case. Generally in the vertical deflection there is required a tube correction by negative bias, whilst in the rapid horizontal deflection an opposite correction is necessary.

The operating tube is in all cases a three-pole tube having an internal resistance as small as possible. In the above example it had an internal resistance of a few thousand ohms.

The use of five-pole tubes is fundamentally possible, but does not result in any advantages. Preferably, therefore, in the case of five-pole tubes the screening grid is connected with the anode, whereby there is obtained the effect of a three-pole tube.

As, owing to condenser 8, the transformer I carries no d.-c. current it mayhave an iron core without air gap and consequently a high input impedance. However, still another condition has to be fulfilled at least by the horizontal (line) deflection transformer. Its frequency, corre sponding to a ZOO-line or 400-line image, amounts to 5,000 or 10,000 periods. A rap-id return movement during approximately of this line period accordingly requires of the transformerthe transmission of a frequency of a twenty times higher periodicity with full amplitude. Since on the other hand a large impedance and accordingly the use of an iron core is absolutely essential,

this high frequency can be managed only when the secondary of the transformer has a very small inner capacity.

The push-pull transformer according to Fig. 5

v.has been found convenient for the practical performance of this requirement. It is of the ironclad type'and is provided with a primary coil Ia:

separated by a high-tension insulation 4 supporting the double secondary winding la, lb.

I claim: r

1. An arrangement for producing the deflecting voltage of saw-tooth wave form for deflecting the cathode ray in cathode ray tubes for television and the like comprising a relaxation generator, an amplifiena transformer having a primary winding being connected via a condenser to the output of said amplifier, and a secondary wind:- ing being connected with the deflecting elements of said cathode ray tube, the input of said amplifier being connected with the saidgenerator, means for integrating the potential occurring at the output of said amplifier, means for superimposing the said integrated potential on the output potential of the amplifier.

2. An arrangement forproducing the deflecting voltage of saw-tooth wave form for deflecting the cathode ray in cathode ray tubes for television and the like comprising a relaxation generator, an amplifier, a transformer having a primary winding being connected via a condenser to the output of said amplifier, and a secondary winding being connected with the deflecting elements of said cathode ray tube, the input of said amplifier being connected with the said generator,

means for integrating the potential occurring at the output of said amplifier, means" for superimposing the said integrated potential on the output potential of the amplifier, said amplifier having an anode resistance being small as compared with the impedance of the said primary winding.

3. An arrangement for producing the deflecting voltage of saw-tooth wave form for deflecting the cathode ray in cathode ray tubes for television and thelike comprisingarelaxation generator, an amplifier, a transformer having'a primary Winding being connected via a condenser A to the output of said amplifier, and a secondary winding being connected with the deflecting elements of said cathode ray tube, the input of said amplifier being connected with the said generator, means for integrating the potential occurring at the output of said amplifier, means for superimposing the said integrated potential on the output potential of the amplifier, the anode resistance of said amplifier being small as compared with the impedance of said primary wind- 4 amplifier being connected with the said generator, an integrating circuit consisting of a condenser shunted by a resistance connected in series to the anode resistance of the said amplifier for integrating the potential occurring at the output of said amplifier.

5. An arrangement for producing the deflect- 7 ing voltage of saw-tooth wave form for deflecting the cathode ray in cathode ray tubes for television and the like comprising a relaxation generator, an amplifier, a transformer having a primary winding being connected via a condenser to the output of said amplifier, and a secondary winding being connected with the deflecting elements of said cathode ray tube, the input of said amplifier being connected with the said generator, an integrating circuit consisting of a condenser and a resistance, the last mentioned condenser and said resistance being simultaneously used for filtering the anode direct current of the said amplifier and for integrating the potential occurring at the output of said amplifier.

6. An arrangement for producing the deflecting voltage of saw-tooth wave form for deflecting the cathode ray in cathode ray tubes for television and the like comprising a relaxation generator, an amplifier, a transformer having a primary winding being connected via a condenser to the output of said amplifier, and a secondary winding being connected with the deflecting elements of said cathode ray tube, the input of said amplifier beingconnected with the said generator, an integrating circuit consisting of a condenser shunted by a resistance connected in series to the anode resistance of the said amplifier for integrating the potential occurring at the output of said amplifier, an ohmic variable resistance connected in series to the said primary winding.

KURT SCHLESINGER.