US2501913A - Noise suppressor tube - Google Patents

Description

Patented Mar. 28, 1950 I UNITED STATES I PATENT, OFFICE NOISE sorrnnsson TUBE Bessie S. Parker, Royalston, Mass. Applleationlanuary 19, 1948, Serialtlo. 3,060

4 Claims.

'irlventiourelams to electronic tubes, and more particularly to a noise suppressor tube.

An object-of. my invention is to provide a improved noise suppressor tube.

Another object of my invention is to provide an electronic tube having a noise suppressor connected to the grid thereof.

Yet another object of my invention is to provide an electronic tube having a noise suppressor connected to the grid thereof, comprising a looped wire having a plurality of transpositions.

Still another object of my invention is to providean electronic tube having means connected to the grid thereof, designed to render the tube noise-reducing, by improving the signal-noise ratio.

A further object of my invention is to provide a noise suppressing element for an electronic tube, comprising three transpositions or loops of wire, said wire having one end connected to the grid at the lead thereof into the tube, one of the loops being outside the range of the anode and the grid.

A still further object of my invention is to provide a noise suppressing element for an electronic tube, comprising three and one half transpositions or loops of wire, said wire being connected at one end to the grid at the lead thereof aligned between the grid and the anode, one of the intermediate loops lying outside the anode, the one-half loop terminating the element in a free end.

With these and other objects in view, which may be incident to my improvements, the invention consists in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements comprising my invention, may be varied in construction, proportions and arrangements, without departing from the spirit and scope of the appended claims.

In order to make my invention more clearly understood, I have shown in the accompanying drawings means for carrying the same into practical eifect, without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In the drawings:

Figure 1 is a diagrammatic representation of a tube in accordance with the present invention,

- together with input and output circuits therefor.

2 is a schematic representation of the suppressor element in relation to grid, cathode, and anode of a triode; and

fill

iii

illustrating the relation of the parts of the tube.

Referring to the drawings, and more particularly to Figs. 1 and 2, there is shown a conventional triode tube T, comprising an envelope 20, an anode or plate P, a gridG and a cathode K. Connected as at Ill to the grid G, is a noise suppressor element designated generally by letter S, comprising a length of transmission wire of the order of .003 in diameter, looped upon itself to form two and one-half transpositions in the electronic area and an intermediate loop outside the space charge. As shown in Fig. 2, a portion of the wire suppressor elements is parallel to the grid for a certain predetermined distance X,

and is crossed or transposed three times as at I2, forming two transpositions l4 and a onehalf transposition I6 in the space charge, and one loop or transposition 18 outside the space charge, the latter being connected to an insulator, not shown, if desired.

It will thus be seen that the improved tube of the present invention (Fig. 3) consists essentially of an envelope 20, enclosing plate or anode P, a grid G enclosing the cathode K, and the suppressor element s arranged as close to the grid as is possible by means of the comparatively short connection I 0. In some cases, mica spacers may be added to hold the suppressor s in alignment,

While a conventional triode tube has been shown for purposes of illustration, it will be understood that other types of tubes may be equipped with the suppressor arrangement disclosed herein, and that when used with other tubes, detailed changes with respect to the spacific arrangement of the suppressor and its placement within a tube may be varied, as will be apparent to one skilled in the art.

The ratios of the various parts of the suppressor are the same for all tubes, the width of the loops being one-half the length, and the short side of the open loop being the same as the width. It will be appreciated that the above ratios are approximate and may require slight adjustment for specifically different tube structures.

The action of the suppressor element is as follows: The grid obtains bias from the plate current drop in RI in the conventional manner, condenser Cl isolating this circuit. The plate load resistor R3 is isolated from the D. C. plate voltage of the tube by means of condenser 02. The suppressor element is internally connected to the grid, and when signal voltage is applied, the action of the element is to allow the tube suppressor element is the same, and may be adapted with little or no apparatus change to any existing audio channel.

In an experimental model, a tube was opened,

the fourth element added as in the figure, and the tube operated as an audio amplifier, with considerable reduction in noise from all causes. This effect is a result of improvement in the signal/noise ratio by limiting the gain and response of the circuit under no signal conditions, and allowing optimum response and maximum gain only when required by the signal.

While I haveshown and described the preferred embodiment of my invention, I'wish it to be understood that I do not confine myself to the precise details of construction herein set forth, by way of illustration, as it is apparent that many changes and variations may be made therein, by those that'are skilled in the art, without departing from the spirit of the invention, or exceeding the scope of the appended claims.

(-I-Iaving thus described my invention and the advantages thereof, I do not wish to'be limited to the details herein disclosed otherwise than as set forth in the claims, but what I claim is:

1. Noise suppressor tube comprising an anode, grid, cathode, and a noise suppressor connected to the grid, said suppressor comprising a looped wire having a plurality of transpositions.

2. Noise suppressor tube comprising an anode, grid, cathode, and a noise suppressor connected to the grid, said suppressor comprising a looped Wire having two and one-half transpositions.

3. A noise supressor tube comprising an anode, a grid, a cathode, and a wire conected to the grid at the lead thereof into the tube, said wire being looped on itself and having three transpositions forming three loops, one of which is outside the range of the anode and grid,

4. A noise suppressor tube comprising an anode, a grid, a cathode, and a Wire connected to the grid at the lead thereof into the tube,

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,975,140 Eitel et al Oct. 2, 1934 2,428,013 Crook Sept. 30, 19 i?

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