US2089695A - Oscillation generator - Google Patents

Description

Aug. 10, 1937. e. w. FYLER OSGILLATION GENERATOR M m n t W m uu W Georg b W 5 I-IiZ Filed March 11, 1936 Patented Aug. 10, 1937 OFFICE OSCILLATION GENERATOR George W. Fyler, Stratford, Conn, assignor to General Electric Company,

New York a corporation of Application March 11, 1936, Serial No. 68,182

I 6 Claims.

My invention relates to oscillation generators and it has for one of its objects to provide an oscillation generator which is adapted for operation over a broad range of wave lengths.

A further object of my invention is to provide an oscillation generator adapted for operation over a number of difi'erent frequency bands including an extremely short wave band and in which the circuits necessary to effect the desired changes irom one band to another are considerably simplified.

i The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, both as to its organization and method of operation together with further'objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawing inwhielr'Figl 1 represents an embodimerit of my invention; .;Fig.' '2repre'sents convennonanytntsunami; generator of Fig. 1 during one ofitsrconditionsofop'eratiomfand Fig. 3 repre ents "a modification offth'e arrangement fip i 2: W

,ner nm'gtt ig."1'I have indicated at I there- 1 in an-' ?electron discharge device provided with a 'unipotential cathode; an anode, and three grids. Thiselectron discharge device is provided with circuits whereby it isadapted to generate oscillationsv in any one of a plurality of frequency bands inaccordance' withthe position 'of a switch 2, 3. 1 This switch comprisesa pair of movable armatures 4 and 5'each of" which operates over '35 a-bank of contacts The armature 4, in the position shown, in the drawing is adapted to connect the grid of the electron .discharge'fdevice' to ground through an oscillating circuit Ba: If it'be moved in t a. counterclockwise direction over the space of twoof its contacts it connects the'grid tq ground -through anoscillatingcircuit C's. Similarly if it be movedfurther in ialcounter-clockdirection it will connect the grid to ground throughoscillating circuitsCs and Ds and in its ultimate position connects the grid to ground through a coil' E. The oscillating circuits A5, B5, C5, and Ds shown on the'drawing may correspond to four 'difierentf bands over which the oscillator' operates when'use'd; for example, ina

v" broadcast receiver of the superheterodyne type to produce 'thehetero'dyne electromotive force. The tuning condenser 'fifwherebyfthe frequency at 1 which these oscillating circuits may be tuned to any desired frequency in each of the different .55 ba qsji conne ed et ee' l i i n n rid of the discharge device and hence effectively in shunt with the oscillating circuit.

The anode of the discharge device is similarly connected through coils Ap, Bp, Cp, and Dp by means of the switch 3 which is operated in unison with the switch 2, each of these coils corresponding respectively to one of the oscillating circuits and being coupled inductively to the coil of the respective oscillating circuit. Similarly in the ultimate positionof the switch 5 the anode of the discharge ,device is connected through a circuit comprising coil E and acondenser l, in parallel, and condenser 8 to ground or through resistance 9 to the source of anode operating potential. V

The band of frequenciesto which the elements A11 and As correspond may be a band below the broadcast frequency range. Elements Bp and B5 may correspond to the broadcast band. The elements Cp and Cs and similarly Dp and D5 correspond respectively to higher frequency bands, whereas the coils E and E correspond to a band of very high frequencies, as for example a range extending from 18 to '70 megacycles. It will be observed that each of the armatures 4 and 5 is provided with a blade 4', 5' respectively, which is insulated from the remainder of the armature as shown and which engages two adjacent contacts so that when the switch is adjusted for operation in the B band the coil A and the coil of oscillating circuit As are short circuited', and similarly when the switch is adjusted for operation in each of the other bandsthe coil in the band next lower in frequency is short circuited.

The oscillating circuit for the short wave band corresponding to coils E and E comprises the coil E, which is permanently connected between ground and the cathode, and in addition it comprises a. coil F, which is permanently connected between the control grid and the arm of the switch 4. These coils are permanently in circuit during operation of the oscillator in each of the other bands but their inductance is so small that they have no detrimental effect upon operation of the generator in those bands.

It will be observed that when the switches 2 and 3 are adjusted for operation'in the A, B, C; or D band, the oscillations are produced by reason of feed-back through COilSAp, As, B B5, etc. in the conventional manner, the tuning being in the grid circuit. When the switches 2 and 3 are adjusted for operation in the E band then' the circuit is substantially that shown in Fig. 2 in l which the reference characters of'Fig. 1 are'applied to corresponding elements of Fig. 2. It will said portion of said range to an extent sufficient to render said operation stable, said means including an oscillatory circuit connected between said anode and cathode tuned to a frequency near said portion of said range and coupled to said first-named oscillatory circuit.

4. The combination, in an oscillation generator, of an electron discharge device having an anode, a cathode, a control grid and a screen grid, an oscillatory circuit connected between said screen grid and control grid, an intermediate point thereon being connected to said cathode, said circuit being tuned to a frequency so wide that operation of said oscillation generator tends to be unstable in a portion of said range, and a tuned circuit connected between said anode and cathode and coupled to said oscillatory circuit, said last-named circuit being tuned to a frequency near said portion of said range whereby stable operation is produced throughout the entire range.

5. The combination, in an oscillation generator arranged for operation at a plurality of frequencies, of a switch for connecting said oscillation generator to operate at either of said frequencies, said oscillation generator comprising an electron discharge device having a cathode connected to ground through a coil adapted for operation at one of said frequencies, a grid connected to ground through a connection comprising a second coil adapted for operation at said one frequency, said connection further comprising said switch and an oscillatory circuit adapted for operation at a second frequency, said switch being arranged to disconnect said oscillatory circuit from said grid and to connect the terminal of said second coil remote from said grid to said cathode, and means including a third electrode in said discharge device to cause oscillations of either frequency to be produced in accordance with the position of said switch, said frequencies being sufficiently diiferent that said cathode is at substantially ground alternating potential during operation at one of said frequencies and at substantial alternating potential during operation at said other frequency.

6. The combination, in an oscillation gener- 3 ator arranged for operation at a plurality of frequencies, said oscillation generator including an electron discharge device having an anode, a cathode and a control grid, of a feed-back coil adapted for operation at one frequency having a primary winding adapted to be connected between said anode and cathode and a secondary winding adapted to be connected between said grid and cathode, means to connect said control grid during operation at said one frequency to one extremity of said secondary winding through a first coil adapted for operation at a second frequency and to connect said cathode during operation at said one frequency to the other extremity of said secondary coil through a second coil adapted for operation at said second frequency, and means to disconnect said feed-back coil during operation at said second frequency from said grid and anode and to connect said grid to said cathode during operation at said second frequency through said first coil and said anode to said cathode through said second coil. GEORGE W. FYLER.

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