US2113225A

US2113225A - Frequency controlled electronic oscillator

Info

Publication number: US2113225A
Application number: US92614A
Authority: US
Inventors: Wolff Irving
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1936-07-25
Filing date: 1936-07-25
Publication date: 1938-04-05
Anticipated expiration: 1955-04-05

Description

April 5, 1938. l. woLFF 'FREQUENCY CONTROLLEDELECTRONIC OSCILLATOR Filed Jul-y 25, 1936 nventor gyf (Ittc'xneg Nek Y N Patented Apr. 5, 1938 FREQUENCY ooNTnoLLED ELEc'rtaoNio osoILLAToR Irving Wolff, Merchantville, N. J., assigner `to Radio Corporation of America, a corporation of Delaware Application July 25, 1936, Serial N0. 92,614

6 Claims.

In its broad aspects, this invention relates to electronic oscillators. More specifically, the invention is a carrier frequency control for a modulated electronic oscillator. y

An electronic oscillator or magnetron may be used to generate ultra high frequency oscillatory currents; i. e., currents of a frequency of thirty megacycles and upwards. If a magnetron oscillating at three thousand magacycles, by Way of example, is modulated, the modulation currents Will not only modulate the amplitude of the oscillations but will greatly vary the frequency of the carrier current. This invention contemplates stabilizing the frequency of the carrier current of a modulated magnetron oscillator.

One of the objects o-f my invention is to provide means for stabilizing the frequency of an electronic oscillator. Another object is to -provide an oscillator for controlling the frequency of the carrier currents of a modulated magnetron oscillator.

A further object is to provide means for preventing a controlling oscillator from being affected by the oscillator to be controlled.

In the accompanying drawing, Fig. 1 represents a schematic illustration of my invention, and

Fig. 2 is a circuit diagram of a modulated vmagnetron oscillator Whose carrier frequency is controlled.

Referring to Fig. 1, a magnetron oscillator I is adjusted to establish a carrier frequency of 3000 megacycles, by Way of example. Signalling or modulating currents are impressed on the oscillator I by a modulator 3. The effect of the modulation currents is to vary both the amplitude and frequency ofthe carrier current. rI lie frequency may be stabilized or controlled Aby impressing` currents of carrier frequency, which are unmodulated, on the modulated oscillator. If the control currents of carrier frequency are impressed directly from the control oscillator 5 on the unmodulated oscillator I, the resulting frequency Will be determined by the relative reaction of the two oscillators. 'I'hat is, the control oscillator 5 may control the oscillator I or be controlled by that oscillator.

The interaction may be prevented by generating currents of a frequency of 1500 megacycles. The currents of 1500 megacycles frequency are transferred to the oscillator I through a frequency doubler 'I. The frequency doubler, as the title implies, increases the control frequency currents from 1500 megacycles to 3000 tional Amodulated"'magnetronv oscillator 9.

megacycles. The frequency doubler not only increases the frequency but it also prevents controlled and controlling oscillators from interacting. Thus the oscillator I is 'frequency controlled or stabilized by the control oscillator 5. Modulation currents may now be impressed on the oscillator I and Will vary the amplitude of oscillation Without varying the frequency of the carrier currents.'

One embodiment of my invention is `.illustrated l in Fig. 2. 'Ihe'magnetronfoscillatorl is composed of Van evacuated envelope.' I I. A pair of anodes I34 and a cathode 'I5 are suitably.v mounted vWithin the envelope III. A magnetic eld, Whoselines of forceare substantiallyv parallel to and surround the fcatho'de, is establishedby a solenoid II', permanent rnagnet, or the like. The

solenoid I1 may beenergized by a battery I9.

The cathode I5 is heated' by a battery2l. The anodes I3Vare' connected to a resonant transmission line 23 which terminates in a dipole antenna 25. The anode circuit is comprised of an anode battery 21, which is serially connected, through the secondary 29 of a Ymodulation transformer 3l and-radio frequency choke coil 33,@2

to la point intermediate lthe ends of the ydipole 25. The modulation is effected by a microphone which is connected through a battery 31 to thev primary 39 of the modulation transformer 3|.

The circuit thus farydescribed is a conven- The control oscillator 4I,' Which'operate`s at half the carrier frequency of themodulated oscillator 9, is comprised of an evacuated envelope 43 which includes a cathode 45 and a pair of anodes 41..

'The envelope is surrounded by a solenoid 49 Which is energized by a battery, 5I. The cathode 45 is energized'bya ybattery 53. The anodes 4I are connected to a resonant transmission line 'T40 55.` An anode battery 5I is connected from the cathode 45 through a radio frequency choke coll 59 to the mid-point of the transmission line 55.

The transmission line 55 is suitably coupled to another transmission line 6I. The latter transmission line is terminated in a full wave rectifier 63, Whose output currents are of double the frequency of the input currents. vThe output of the rectier is impressed on a pair of enclosed quarter Wave lines 65, 61 between terminals which offer a suitable impedance match for the full Wave rectifier, or frequency doubler.

The quarter Wave lines 65, 61 are respectively connected to the transmission line 23 by leads 69, 1I which include "trombones 13, 15 or the like, for tuning the connecting lines S9-l I. The several transmission lines may be terminated in sections of line which offer suitable impedances. Inasmuch as constant frequency is desired, the oscillators and transmission lines should be carefully designed and constructed to minimize changes caused by the ambient temperature, vibration, voltage variations, and the like.

Thus I have described a modulated magnetron oscillator. The carrier frequency currents generated by this oscillator are controlled. The controlling oscillator creates unmodulated oscillatory currents which have half the frequency of the modulated carrier currents. The frequency of the controlling oscillator currents is doubled by full Wave rectiiers or the like. The controlling currents of the frequency of the carrier are impressed through suitable transmission lines on the modulated magnetron oscillator to stabilize or control the frequency of the carrier currents and thereby prevent frequency modulation.

Although I have chosen magnetron oscillators to illustrate my invention, it should be understood that Barkhausen-Kurz or any type of ultra high frequency oscillatormay be used. Like- Wise the controlling frequency may be made less than half of the carrier and multiplied by more than two to control the carrier frequency.

I claim:

1. An ultra high frequency system comprising an ultra high frequency oscillator for generating carrier frequency currents, means for impressing modulating currents on said oscillator, a second oscillator for generating currents of less than said carrier frequency, means for multiplying the frequency of said controlling current to equal the carrier frequency, a pair of resonant lines for stabilizing the frequency of said multiplied frequency currents, means for impressing said multiplied frequency currents on said pair of resonant lines, and means for impressing said multiplied and stabilized frequency currents on said ultra high frequency oscillator to thereby control said carrier frequency currents.

2. An ultra high frequency system comprising an ultra high frequency oscillator for generating carrier frequency currents, means for impressing modulating currents on said oscillator. a second oscillator for generating currents of -half said carrier frequency, means for doubling the frequency of said controlling currents, a pair of quarter wave resonant lines for stabilizing the frequency of said doubled frequency currents, means for impressing said doubled frequency currents on said pair of resonant lines, and means for impressing said doubled and stabilized frequency currents on said ultra high frequency oscillator to thereby control said carrier frequency currents.

3. An ultra high frequency system comprising a magnetron oscillator for generating carrier frequency currents, means for impressing modulating currents on said oscillator, a second oscillator for generating currents of less than said carrier frequency, means for multiplying the frequency of said controlling currents to equal the carrier frequency, a pair of quarter wave resonant concentric lines for stabilizing said multiplied frequency currents, means for impressing said multiplied frequency currents on said pair of concentric lines, and means for impressing said stabilized multiplied frequency currents on said magnetron oscillator to thereby control said carrier frequency currents.

4. An ultra high frequency signalling system comprising, in combination, a magnetron oscillator for generating carrier frequency currents, means for modulating said carrier frequency currents with signal impulses, a second oscillator for generating controlling currents of half said carrier frequency, means for impressing currents from said second oscillator on a full Wave rectifier, a pair oi' enclosed quarter wave length lines resonant to the output currents from said rectifier for stabilizing the frequency of said rectifier currents, means for impressing said rectified currents on said quarter Wave length lines, and means for impressing the output currents thus stabilized on a transmission line coupled to said magnetron oscillator for controlling the frequency of said carrier currents.

5. The method of controlling the frequency of modulated ultra high frequency carrier currents by means of a concentric resonant line which comprises generating an ultra high frequency carrier current, modulating said carrier current, and generating an unmodulated controlling current of a frequency equal to said carrier, stabilizing the frequency of said unmodulated controlling current by applying said current to said concentric resonant line, and applying said frequency stabilized controlling current to said modulated ultra high frequency carrier to control the frequency of said carrier currents.

6. The method of controlling the frequency of modulated ultra high frequency carrier currents by means of a resonant line which comprises generating an ultra high frequency carrier current, modulating said carrier current, generating an unmodulated controlling current of lower frequency than said carrier frequency, multiplying said lower frequency current until its frequency equals said carrier frequency, stabilizing the frequency of the currents of said multiplied frequency by applying said multiplied frequency currents to said resonant line and impressing said multiplied and stabilized frequency current on said modulated ultra high frequency carrier to control the frequency of said carrier currents.

IRVING WOLFF.