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Dec. 14, 1948. R. P. OWEN 2,456,016 KEYED OSCILLATOR Filed Sept. 16, 1944

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?ea-6-f (2-4%. 4. INVENTOR. Patented Dec. 14, 1948 : '....: 2,456,016

UNITED STATES PATENT OFFICE Robert P. Owen, Passaic, N.J., assignor to Allen B. DuMont Laboratories, Inc, Passaic, N.J., a corporation of Delaware...... Application September 16, 1944, Serial No. 554,382

4 claims. (CL 250-36). 2 This invention relates to a Oscil cause of the low alternating current plate to lator by which trains or bursts of Oscillations, resistance of tube 9, which is effectively either sinusoidal or of other shapes, can be Sud across the tank coil 5. The 2 prevents denly initiated and caused to continue for prede "excessive current, through tube 9. termined intervals of time and then be suddenly. F. However, when a negative pulse as indicated at stopped. With this invention the initiation of 24, is applied to the control grid 26 of tube 9, the oscillations and the stopping of the Same...is 'this tube: ceases to conduct, thus causing its plate under the control of another vacuum tube and to cathode impedance to become very high, may be done by means of a pulse of electrical whereupon the Oscillator begins to oscillate in energy that may be termed "keying pulse.' 0 stantly at the frequency determined by the grid The invention may be understood from the de tank circuit 4, 5 and continues to oscillate dur scription in connection with the accompanying ing the time interval of the negative pulse 24 and drawing, which is a diagram of connections then immediately ceases to oscillate as shown by showing an illustrative embodiment of the in the burst 27 of high frequency oscillations. vention. 5 It will be obvious from the description that In the drawing, reference character indicates with this invention a vacuum tube oscillator can the vacuum tube of a transitron oscillator which be keyed in such a manner that it will oscillate is provided with a plate 2, cathode 3, and three for predetermined periods of time so that trains grids 4, 5 and 6, the grid 6 being grounded. or bursts of oscillation, whether of sinusoidal or A resistor 7 is provided between a source of ; other forms, can be suddenly initiated, prolonged positive potential B and the plate 2. A resistor for different intervals of time, and immediately 8 is provided between the plate 2 and ground with extinguished merely by applying the appropriate a condenser 9 in parallel with the resistor 8. A signals to the grid of tube 9. variable resistor O is provided between the cath What is claimed is: ode 3 and ground with a condenser if in parallel 1. A device for producing bursts of electrical with it. A condenser f2 is connected between the Oscillations, which comprises a that has grids 4 and 5 and a resistor 3 is located between its control grid grounded and its cathode con grid 4 and ground. nected to ground through a resistor, a condenser A condenser 4 and inductor 5 in parallel be and inductance in parallel connected between a tween a source B of positive potential and the 30 Source of positive potential and the screen grid grid 5 constitutes the tank circuit of this grid of Said pentode, a resistor between the suppressor and controls the frequency of oscillations of the grid of Said pentode and ground and a condenser tube in the known Way. between the screen grid and of The output lead from the oscillator f is indi Said pentode to cause said pentode to oscillate cated by 6. A lead 7 is connected from the 35 when positive potential is applied to its plate, a lead 6 to the plate 8 of the 9 which is triode adapted to be blocked when a pulse of neg the keying tube for the device. It has its cathode ative potential is applied to its control grid, the 20 biased by resistor 2 with which the condenser plate of said triode being connected directly to 22 is in parallel. Said Screen grid and its cathode connected to The keying pulse 24 is coupled by condenser 25 40 ground through a resistor. to the control grid 26 of the tube. 9. This grid 2. A device for producing bursts of electrical 26 is connected to ground through resistor 27. Oscillations, which comprises a pentode that has The operation is as follows: its control grid grounded and its cathode con The pentode f is connected as shown as a nected to ground through a resistor, a condenser transitron oscillator. It has been found, for ex 45 and inductance in parallel connected between a ample, that the device operates very satisfactorily Source of positive potential and the screen grid when the resistor is adjusted to be about 300 of Said pentode, a resistor between the suppressor ohms and the potential B-- is about 85 volts, grid of Said pentode and ground and a condenser A wide range of frequencies of oscillation of the between the screen grid and suppressor grid of Oscillator can be obtained by changing the con Said pentode to cause said pentode to oscillate denser 4 or inductance 5. It has been found when positive potential is applied to its plate, a that frequencies up to about one megacycle or triode adapted to be blocked when a pulse of more per second are very satisfactory for the pur negative potential is applied to its control grid, poses of this invention. the plate of said triode being connected directly The oscillator does not oscillate normally be 55 to Said Screen grid, and separate con 2,456,016 3 4. necting the of said pentode and triode between the screen grid and Suppressor grid of respectively to ground. said pentode to cause said pentOde to OScillate 3. A device for producing bursts of electrical when positive potential is applied to its plate, a oscillations, which comprises a pentode that has triode adapted to be blocked when a pulse of neg its control grid grounded and its cathode COIn 5 ative potential is applied to its control grid, the nected to ground through a resistor, a condenser plate of said triode being connected directly to and inductance in parallel connected between a said screen grid, a variable resistor between the source of positive potential and the screen grid cathode of said pentode and ground and a re of said pentode, a resistor between the Suppressor sistor between the cathode of said triode and grid of said pentode and ground and a condenser 10 ground. between the screen grid and suppressor grid of ROBERT P. OWEN. said pentode to cause said pentode to Oscillate When positive potential is applied to its plate, a REFERENCES CTE) triode adapted to be blocked when a pulse of negative potential is applied to its control grid, The following references are of record in the the plate of said triode being connected directly l6 file of this patent: to said screen grid, and separate resistors con UNITED STATES PATENTs necting the cathodes of said pentode and triode respectively to ground and a condenser in parallel Number Name Date With each resistor. 1839,650 Cook ------Jan. 5, 1932 4. A device for producing bursts of electrical 20 2,088,229 Braden ------July 27, 1937 oscillations, which comprises a pentode that has 2,213,398 Kircher ------Sept. 3, 1940 its control grid grounded and its cathode con 2,273,193 Heising ------Feb. 17, 1942 nected to ground through a resistor, a condenser OTHER REFERENCES and inductance in parallel connected between a 25 “The Transitron Oscillator,' by Cledo Brunetti, source of positive potential and the screen grid Proceedings of the I. R. E., pages 88-93. Copy in of said pentode, a resistor between the Suppressor Library. grid of said pentode and ground and a condenser