US2265825A - Impulse segregation circuits - Google Patents

Description

Dec. 9, 1941. R. URTEL EFAL 2,265,825

IMPULSE SEGREGATION CI RCUITS Filed Sept. 10, 1938 F'gd INVENTORS RUDOLF UR TEL, MAX GE/GFR BY AND R E ANDR/EU A'i'TdRNEY iatentecl Dec. Q, 1941 UNET ED ST a OFFlCLE- Gesellschaft fiir Drahtlose Telegraphic :m. b. H., Berlin, Germany, a corporation of Germany Application September 10, 1938, Serial'No. 229,254 In Germany June 29,1937

Berlin, Germany,

6 Claims.

In the signalling and intelligence transmission arts, the problem arises frequently to separate impulses of different lengths in a mixture from one another to enable them to operate and'control different devices. Especially in television receiver apparatus which are Worked by the single-channel synchronizing system the line deflection or the frame or the line series generator or time-base are controlled from the incoming mixture of synchronizing signals or impulses. The various signals which actuate these two deflector means distinguish themselves in all conventional systems essentially by their time duration or length; in fact, the frame impulses are much longer than the line impulses.

For the sorting or separation of these signals Which are to be made operative only at the devices co-ordinated to them, recourse is had as a general rule to the time integration of a current. The time-constants which the deflection generators or time-base means involve are so chosen that the brief impulses are able only to operate the line deflector means, and that the frame deflection generator which has a greater time-constant can only be excited when the impulse potential persists for some longer period of time, in other words, when a long picture or frame impulse arrives.

Now, these methods predicate for their operation upon an integration effect inhere this basic disadvantage and difficulty that they are very sensitive to disturbing or stray actions which happen to fall upon the receiver apparatus; for these stray effects are also included in the integration, and this circumstance is liable to seriously impair the dependableness and safety of operation of such an arrangement. Hence, the present invention discloses ways and'means which is free from such shortcomings.

The mixture or spectrum of impulses is simultaneously fed to both deflector means. The line deflection generator or oscillator reacts to line impulses in a way well known in the art. The time-constant which is decisive for and determines the actuation of the picture or frame deflection generator or line series deflection generator difiers only a very small amount from that of the line deflection generator with the result that the frame deflection or frame scan would be rendered operative also during the duration of the line scan impulse, but slightly later than the line deflection, if it were not for the fact that the frame scan means, according to the invention, are blocked. This blocking of the frame deflection generator is effected by the aid of a voltage derived from the line deflection generator just working'at the time.

Fig. l is a set of explanatory curves.

Fig. '2 is one embodiment of our invention.

3 is another embodiment of our invention.

The shape of the impulses'and the voltages derived therefrom is shown in Fig. 1. a. represents the incoming mixture of impulses; his the same mixture as brought to act at the frame deflection their efieet. {i represents the voltage which actually controls the frame deflection generator. When a picture or frame impulse arrives, just as in the conventional scheme, the line deflection generator is rendered operative; but since its operation is independent of the length or durationof the impulse which simply initiated the action, the incidentally generated blocking or cut-off potential is active for justthe same length of time as upon the arrival of line impulses. But then the frame scan-is safely initiated.

The difference between the method here dis closed and the integrating methods is that each deflection generator'isexcited by a steep impulse front. The delay occurring between the arrival of the frame impulse and the beginning of frame deflection or scan is not based upon integrator action. In fact, this of necessity would involve a rounding of the releasing impulse and would thus introduce a certain element of uncertainty as to the instant of startof the action to be initiated or released. v v

Quite apart from the fact that the invention is free from the said drawbacks inhering in integrating methods, the invention offers the further advantage that it will'be found useful in the handling of no matter what kinds of mixtures of short (line) and long (frame or picture) impulses may be concerned.

Two arrangements which operate in the manner above indicated shall be described in more detail in what follows by reference to Figs. 2 and 3. Referring to Fig. 2, the impulse mixture is simultaneously fed by way of respective condensers to the grid of a Thyratron I for'line scan and of a Thyratron 2 for frame or picture scan. In series with the grid of Thyratron 2 is a small RC mesh 3, 4, designed to slightly round or lap off the face of the impulse. Included in the plate leads are the resistances 5 and 6 through which are charged the condensers l and 8. When a generator is rendered operative by an impulse its condenser becomes discharged through the discharge vessel having incidentally been rendered conducting for current. When the discharge has been completed, the operation of the generator ceases again, and the charging process of the condenser is resumed. The sawtooth shaped Voltage wave arising at the same serves for the control of the deflection or sweep of the cathode-ray pencil. In series with the cathode of Thyratron I is connected a resistance 9 across which a positive potential arises each time that a current flows through the Thyratron I; and this voltage is impressed upon the cathode of Thyratron 2 with the result that the latter is rendered inoperative.

Referring now to Fig. 3, it will be seen that the time base or sweep means comprise two socalled blocking oscillators, that is to say, oscillator devices in which there is a'strong feedback between the plate and the grid circuit of the electronic tube. The impulse mixture is applied to the resistance H and I2 in the grid circuit of the line deflector tube I0. Tube I serves to cause release of the discharge of the condenser l being charged through the resistance I l; when the tube is blocked, the, condenser [E is slowly recharged. Upon the grid circuit of the frame deflection generator is impressed the impulse mixture by way of a small RC mesh comprising resistance II and condenser I3 which insures gentle rounding of the front of the impulses. The frame deflection generator comprises a discharge vessel of the hexode type I6. The first grid ll of the latter is included in the oscillatory circuit. Its third grid I8 is blocked by a potential which arises in the line deflection generator upon the discharge of the condenser [5 across a resistance 19 being in series with the latter. The sawtooth voltage waves arising at the condensers l5 and 20 serve for the control of the deflection or sweep of cathode-ray pencils.

The present invention, as will be understood,

is not confined to sweep or deflection means in television receivers. In fact, the same may in an analogous manner be used in all equipment where different signals contained in a mixtureare to be sorted or separated to serve for the control of different means, such as apparatus used in telegraphy and telephony.

What we claim is:

1. Apparatus for generating deflecting signals received from the external source, and means for developing a signal within one of said generators to block the other of said generators during a predeterminable period of time.

2. Apparatus in accordance with claim 1 wherein said generators comprise a pair of interlocked relaxation oscillators.

3. Apparatus in accordance with claim 1 wherein said generators comprise a pair of interlocked relaxation oscillators of the feed back type.

4. Apparatus for generating deflecting signals for deflecting an electronic beam in two coordinates of deflection comprising a first means for storing electrostatic energy, a discharge path for said energy connected substantially in parallel with said aforementioned first storage means, means for rendering said first discharge path conducting in accordance with signals received from a source external to said apparatus, a second means for storing electrostatic energy, a discharge path connected substantially in parallel with said second electrostatic energy storage means, means for developing from said first discharge path a control potential when said path is rendered conducting by the signals from the external source, and means for impressing said control potential onto said second discharge path to control the discharge state thereof.

5. Apparatus for generating deflecting signals for deflecting an electronic beam in two coordinates of motion comprising means for receiving signals representative of each co-ordinate from a source external to the apparatus, a first relaxation oscillator comprising a first thermionic tube having anode, cathode and at least one control electrode,- means for storing electrostatic energy connected substantially in parallel with the anode-cathode path of said tube, means for impressing said signals from an external source onto the control electrode-cathode path of said tube, means for developing a pulse in accordance with the discharge of the energy in said electrostatic energy storage means, a second relaxation oscillator comprising a thermionic tube having anode, cathode and at least one control electrode, electrostatic ener y storage means connected in the anode-cathode path of said second thermionic tube, means for impressing said signals onto the control electrode-cathode path of said second thermionic tube and means for impressing the pulses developed within the first relaxation oscillator onto a control electrode-cathode path of said second relaxation oscillator to block the action thereof for a predeterminable period of time.

6. Apparatus in accordance with claim 5, wherein there is included a time constant circuit in the control electrode-cathode path of said second relaxation oscillator.

RUDOLF URTEL. MAX GEIGER. ROBERT ANDRIEU.

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