US1760162A

US1760162A - Radio tuning means

Info

Publication number: US1760162A
Application number: US745985A
Authority: US
Inventors: Byron B Minnium
Original assignee: Story & Clark Radio Corp
Current assignee: Story & Clark Radio Corp
Priority date: 1924-10-27
Filing date: 1924-10-27
Publication date: 1930-05-27
Anticipated expiration: 1947-05-27

Description

May 27, 1930. B. a. MlNNlUM RADIO TUNING MEANS Filed Oct. 2'7, 1924 Patented May 27, 1930,

UNITED STATES I meals-2 PATENT orrlce BYRON B. MINNIUM, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, 'IO

STORY 86 CLARK RADIO CORR, OF CHICAGO ILLINOIS, A CORPORATION OF DELA- WARE RADIO TUNING IvIEAN'S Application filed October 27, 1924. Serial No. 745,985. I

This invention relates to radio apparatus, and contemplates certain improvements for the purpose of more effectively tuning the apparatus, thereby to prevent certain undesir-able effects, especially in receiving, and

to insure accurate and more delicate adjustment of the apparatus in accordance with any particular wave length or frequency.

Generally stated, therefore, the object of the invention is to provide improved means for more accurately and delicately tuning radio apparatus of any suitable known or approved character, but more especially adapted for use in tuning apparatus of thls kind in which vacuum tubes are employed,

in the well known manner.

To the foregoing and other useful ends, the invention consists in the matters hereinafter set forth and claimed, andas shown in the accompanying drawing, in which the single figure is a diagram of a radio receiving hookup or circuit arrangement embodying the principles of the invention.

As thus illustrated, the receiving hookup or circuit arrangement shown is of a well known form, comprising the aerial 1 connected through the repeating coil 2 to the ground at 3, and provided with three vacuum tubes 4:, 5 and 6, together with batteries 7,

8 and 9, connected in the manner shown. The receiving instrument 10 may be of any suitable known or approved form, and is preferably connected in circuit as shown.

The improved tuning means, constituting the invention, include the adjustable condenser 11 connected in shunt of the plate 12 and the grid 1?) of the vacuum tube 4 previously mentioned; and said tuning means include, also, the similar adjustable condenser 14 connected in shunt of the plate 15 and the grid 16 of the vacuum tube 5 previously mentioned.

The coil 17 is connected in series with the stopping condenser 18, and the two are connected in shunt of the condenser 11, previously mentioned; and in a similar manner, the coil 19 is connected in series with the stopping condenser 20, and the two are connected in shunt of the condenser 14: previously mentioned. The

condensers

18 and 20 may each be of one microfarad capacity, for example, or of any capacity, which. will keep the plate voltage from reaching the grid of each vacuum tube. The adjustable condenser 21 is in shunt of the secondary of the coil 2, and similar tuning condensers 22 and 23 are provided. for the input circuits of the tubes5 and G, as shown, and each con denser 21, 22, or 23 is adjustable independently of the condensers 11 and 14, for thereby tuning the input circuits of each tube.

WVith this arrangement, and by adjusting the condenser 11, the parallel circuit comprising elements 11 and 17 and the capacity between the grid 13 and the plate 12 may be tuned for any particular incoming frequency; and by adjusting the condenser 14, thesame tuning effect will be obtained in connection with the plate 15 and the grid 16 previously mentioned. This insures a more accurate and delicate tuning adjustment than is ordinarily obtainable, in a receiving apparatus employing vacuum tubes, and tends to insure better reproduction.

Ordinarily, of course, there is nothing in shuntof the plate and the grid of the vacuum tube or lamp, in radio apparatus of this kind, having tuning means (such as 21) for the input circuit of a tube, and under such circumstances there is quite liable to be a reaction from the output circuit of the lamp or tube back into the input circuit of the lamp, so called, producing a disturbance in the receiver or reproducing instrument, and sometimes preventing the receiving apparatus from working properly. In other words, with the ordinary arrangement, which would be exemplified by the circuit arrangement shown, but without the condensers 11 and 14 and the coils 17 and 19 and the condensers'lR and 20, there is quite liable to be some d turbance due to the reaction from the output circuit of the lamp or vacuum tube, back into the input circuit thereof, but with the tuning arrangement shown in shunt of the plate and grid of the lamp or tube, such disturbance is prevented or greatly reduced. It will be understood of course that coils 17 and 19 are inductors of suitable character.

Without disclaiming anything, and With- 'ber, 1924.

out prejudice to any and all novelty shown and described, what I clalm as my 1nvent1on is I 1. Radio receiving apparatus provided with a vacuum tube havinga plate and a grid and a filament, having adjustable tuning means providing one and the same shunt path of fixed resistance for all frequencies or wave lengths to permit feed back connected in shunt of said plate and grid, the input circuit of the tube including the secondary of a transformer, and adjustable capacity in shunt of saidtransformer secondary, adjustable relatively to and independently of said adjustable tuning means, one sine of said capacity being connected to one terminal of said filament, and the other side of said capacity b wing connected to said grid, whereby the input circuit of said tube may be tuned by said capacity for different frequencies or wave lengths, and such tuning may be improved by said first mentioned tuning means.

2, Apparatus as specified in claim 1, said adjustable tuning means comprising an ad justable condenser in' a low resistance and otherwise continuous shunt path, and including a stopping condenser and acoil in series, the coil being arranged in non-inductive relation to all'portions of said apparatus, said adjustable condenser being connected in multiple with said coil and stopping condenser, whereby said coil and adjustable condenser are in parallel circuits.

3. Apparatus as specified in claim 1, said adjustable tuning means comprising an adjustable condenser in a low resistance and otherwise continuousshunt path around the grid plate and in series with said secondary.

4. Apparatus as specified in claim 1, said tunin means comprising a 0011 111 non-1nductive relation to all portions of said apparatus and a fixed condenser in series.

5. Apparatus as specified in claim 1, said rillllllt having both fixed and adjustable capacity in parallel circuit paths therein. 7

6. Apparatus as specified in claim 1, said tuningmeans having fixed inductance in noninductive relation to all portions of said apparatus.

7. Apparatus as specified in claim 1, said shunt having capacity in 1 parallel circuit paths therein.

Specification signed'this 23rd day of Octo- BYRON 'B." MVINNIIUM.