US2439735A

US2439735A - homrighous

Info

Publication number: US2439735A
Authority: US
Publication date: 1948-04-13
Anticipated expiration: 1965-04-13

Description

April' 13, 194s.

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J. H. HCMRIGHOUS ELECTRIC/u.. confrnox. ssrml4 Original Filcd Sept. 17, 1942 3 Shoots-Sha. 2

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Patented Apr. 13, 1948 ELECTRICAL CONTROL SYSTEM i Y John B. Homrighons, Oak Park, IIL- "ff" Original application September 17, 1942,- Serial "l' My invention relates to improvements in elecl Divided and this, application' october 16,1944,seriaiNe. ss,9az' t somme. (ci. 25o-41.5) 5

trical control and distribution, more particularly tion with the supply current.

This invention will be described in connection with a' television system. but it is to be understood that it is not limited to such uses.

Other objects, features, and advantages of my invention will appear from the following description taken in connection with the accompanying drawings, illustrating an embodiment thereof in which:

Figures 1 and 2 are simplified diagrammatic views of a television transmitting station and a television receiving station,V respectively, illustrating the principles applied in this invention.

Figure 3 is a motor driven device for generating control frequencies.

Figures 4 and 5 are end views of the disks shown in Figure 3 for generating the control or frame frequency.

Figures 6 and 'l are simplified diagrams showd ing the circuit figure numbers used in generating the sweep frequencies.

Figures 8, 9. l0, and 11 show circuits used in my invention. e

.Figure 12 shows a motor and control circuit.

Figure 13 shows an end view of disk used in Figure 12.

Figure 14 shows picture control character, re-

produced at the receiver.

In Figure 1, the numeral I designates a cathl another carrier produced by ode-ray pick up tube of the conventional type and is known as an iconoscope. It is to be understood that other tubes such as orthiconoscope" developed for perpendicular scanning of all points on the mosaic, or the tube known as the image dissector may be used instead of the one illustrated. As shown, the tube comprises a mosaic, photo-electric screen on which a. light image of the object is projected and produced, and an electron gun for generating av ray of electrons directed at the screen, and two sets of deecting plates for deecting the electron ray at the line and eld frequencies, so that it is caused to scan the screen. The picture and certain other control characters are thereby developed and fed from the metallic plate by an output connector 2 to a modulating amplifier 3.

A carrier wave is provided by an oscillator I in the power issnxpliiler/L This carrier wave is modulated by the frequency band video or pic ture signals through the modulation ampliiier 3.

The signals from the amplifier 'l are supplied by a connection 8 to the mixing circuit 9. Certain control. signals are also transmitted video signals. w

The numeral- IB designates 'a generator for producing pulsating voltage waves or waves of sine iorxnior controlling the sweep frequencies at the desired frame frequency. T he low frequency `sweep control voltage waves or signals through the mediumo'f amplifier il, modulate ampliiersta'ge-43.`v v

The audio o'r sound signals fromthe microphone M are passed through alu-*amplifier i5.

The sweep control signals and the audio signals are applied through a.- mixer circuit i6 to modulate a second inain carrier wave in the power amplier stage I1 produced by the oscillator Il.

The signals from'the amplier I1' are fed to the mix'er circuit.l 9 through the conductor i9. 'I-'he two carrier waves,` one modulated by sweep frequency control signals and audio signals, the

other modulated by video signals are mixed in the mixer circuit 9- and fed to the common antenna 26 for transmission by radio;

The sweep control signals' are' transmitted in the form of sine waves, which are used to synchronize or control the scanning action with the transmitter.

The antenna-2`| receives the combined carrier' signals from the transmitter antenna 20 to a v After suitable amplification, the video signals are detected at 21 and fed by a connection 28 to a reproducing' device' 29. rIhe device 29 is represented as being in the form'- of a.4 cathode-ray tube of well known construction, and-comprises a fluorescent screen, an electron gun for developing t aray ofelectrons directed toward the screen,A

and two sets of electrostatic plates for deilecting th`e electron ray at the-line' and field frequencies to cause it-t scan the screen.- It is to be understood that electromagnetic means may be used for deecting the electron ray. The video signals v are applied to a' control electrode of the electron gunto` change the intensity of the electron-ray' in aocordance'vvilsh picture or video signals.

Referring: to the intermediate frequency stage 25 which contains the sweep signals and the audio signalsl and through the action of the second detector 30 the output of which goes to two selective filters` 3i and 32. The low frequency sweep control signals after leaving the illter 3|, still in modulated form ona carrier are demoduoscillator I2 in its I 11 inclusive.

` nals, or the signals may be used after suitable ampliilcation to directly control the scanning @sans From the above description it `will be seen that each revolution o! th- :lisk 42 will produce two action at the' receiver which will be explained in more detail later.

The audio signals from theiilter 32- may be fied to the loud speaker 35. v -Referring to Figure 3, the numeral S represents a motor which is operated from the local supply current and normally runs at approximately 1800 R. P. Operated from the motor through the action of a cone shaped pulley 39 andthe contacting pulley 4U are two disks oi light polarizing material' 4| and 42, revolving normally at approximately 1800 R. P. M. and revolving paststationary pieces of

polarizing material

43, 44, and 45 and also separate sources of light 46, 4l and 48 respectively; I

The revolving and stationary members are bet ter shown in Figures 4 and 5. In Figure 4 the disk 42 is made up of two halves of polarizing mateiial; each half may be rotated through a very small angle and as shown on the drawing the planes of polarization are not parallel. This angle depending upon the desired size o! the dark portion 49 or the period of the gap between pairs of pulses as illustrated at 5D.

From the above it will be seen that when the disk 42 is rotated past the stationary member 45 and between its source of light 48 and photo- A there is a gap 49 in the disk 42 successive imsimilar impulses in the transformer winding 55 to trigger the discharge tube 58. The tube 5l may bebiased so that only the positive pulses applied to the grid will operate the tube. Since pulses will occur at differently spaced intervals. Changing the speed o1 the disk by the adjustment of the cone pulley 39 will change the picture rate without changing the number or lines per picture.

The control voltages produced in Figure 8 may vibe transmitted to the receiving station togovern the scanning thereat. l

The pulses generated by the disk 42 canbe used to produce the line scanning control pulses by inw'. terposing frequencymultipliers between the cirelectric cell 5|, that the intensity of the light reaching the photo-cell will vary from zero to maximum value and back to zero when rotated through approximately 180 degrees.

Referring to Figure 5, the numeral 4i represents a disk of light polarizing material having a certain part painted or blacked out so that rotatingv it in a clockwise direction past its stationary polarized' member 43 and 44 and between its sources of

light

46 and 41 and their respective photo-

cells

52 and 53 the intensity of light reaching each photo-cell will vary from zero value to maximum value and back to zero during one half of a revolution Vancl during the other half of the revolution there will be no light change.

A system for producing the proper sweep voltages and control signals is shown in Figures 8 to In Figure 8 I have shown a photocell 54 which may be the photo-cell 5i in Figure 3. This cell is responsive to the variations of light cuits of Figures 8 and 9. I may also use disk 4I having associated with it two sources of light 4I and 4l and their respective photo-

cells

52 and 52. These cells are, responsive to the variation o! light intensity caused by the rotation of the disk 4I al I previously explained.

Referring to Figure 11, I have shown a circuit for producing an alternating current from the variationof light occurring in the' photo-

cells

62 and 63 which may be the photo-

cells

52 and 53 shown in Figure 3. These photo-cells control 'the grid excitation of

grids

64 and 65, of amplifier tubes 66 and 6l; the anodes 68 are connected.

in parallel through the primary winding of transcrease the current oi tube 66. The photo-cell 68 intensity caused by the rotation of disk 42 as prethe transformer primary winding 69, whereby, gj

` alternating voltages are induced in the secondary to thereby produce pulsating voltages for controlling the discharge tube.

scanning I employ a grid controlled discharge tube circuit shown in Figure 9, where the pulsating voltages from transformer winding 56 are induced into the transformer secondary winding to drive the grid of tube 58 positive, discharging To produce the de- A sired output wave of saw tooth form for ield winding. These control voltages from winding 6I may be induced into thetransiormer winding of Figure 9' to control the vertical deliection, and b! changing the speed of rotation of the disk 4| the duration of the time per iield is changed so that any desired number oi frames per second may be produced.

One method or system for producing inter-lace' scanning uses the disk 4|, Figure 5 with Figure 11. to develop impulses to trigger the sweep generator, Figure 9, to thereby control the vertical reciprocating movement of the electron ray at different vtime intervals whereby one eld period will be greater than in the intervening lleida.

and a sine form wave to modulate a carrier as.

previously explained. The circuit ligure members shown in Figure 7, plus Figure 3, constitute the frequency generator shown at i0, Figure 1.

It is proposed to use frequency multiplying circuits for the purpose of producing the high frequency required for horizontal line scanning. 'I'he field frequency` is obtained asl described above and from these frequencies vthe higher line flequencies are produced.

Referring to Figure l0, two stages of frequency multiplication are shown. The secondary winding 78 is inductivcly connected tn the transformer winding G9 in Figure l1 which supplies alternating pulses to the taped secondary and in turn to the full wave rectiier tube i9 which delivers twicev the number of pulses or cycles to the tuned lter comprising the condenser 80 and the next transformer primary winding 8l. This double cycle signal is supplied by the taped secondary 82 to the full wave rectifier 83 where it is again doubled and fed to the next succeeding transformer primary 84. The taped secondary 85 delivers alternating current to the next stage and so on until the desired high frequency for line scanning is obtained. While I have shown a circuit to double or to multiply the frequencies. other frequency multiplying circuits may be used.

With reference to Figure 7, I have provided two switches 8B and 81 for shorting out one or more stages of doublers; for instance, certain stations could be operating on 256 lines per field and other stations on 128 lines per field.

The circuit figure number shown in Figure 7, omitting Figure ll, may constitute in one receiving station the frequency generator shown at 34, Figure 2.

From the above description it will be seen that the line pulses are definitely locked with the field pulses, or in other words, the same pulse that triggers the vertical deection also supplies through multiplyingv circuits the trigger pulses for line scanning.

Furthermore. from the above description, the control of the field and line defiecting circuits at the receiver from the sine form voltage wave transmitted by radio from the transmitting station will cause the cathode-ray or electron ray at the viewing tube to be in exact synchronization with the cathode-ray in the pickup tube, whenever the receiving station is tuned to the proper carrier wave..

Another system for controlling the scanning operations at the receiving station may comprise the motor 94, Figure 12, having control circuits for keeping the position of the rotor in step with the alternating current signals. The motor SI drives disks or mechanisms similar to those ex- -plained in connection with Figure 3 to in tum develop line and field trigger potentials, utilizing the circuits shown in Figure '7. The motor and mechanism shown in Figure 12, together with the circuits shown in Figure 7 may constitute the frequency generator 3I,`Figure in another receiving station. The power amplier 95 may 6, be supplied with signal current from the detector 33, Figure 2. These signals, after proper ampllilcation at 95, are fed to the motor 94 through contact 98 and 91. The half wave rectifier 98 will supply the positive pulses to one winding of relay 99; The motor 94 is small and carries a -k very light load; therefore very little power is required to operate it. Secured to its shaft are.

three disks of polarizing material, two of which are exactly like those shown in Figures 4 and 5 with their associated stationary polarized members and photo-cells. The disks are designated by the same numbers 4I and 42 and operate the 'circuits .shown in Figure 7, 'as previously explained,

in connection with the transmitting station. In the preferred embodiment of my invention I propose to substitute the disk IDD, Figure 13, for the disk 4| to thereby develop a series of trigger impulses having equally spaced periods of time.

The third disk in Figure 12, designated Illll. and like the view shown in Figure 13. is secured to the motorshaft in such a manner that when it is rotated one half of a.' revolution to alter the light in the photo-cell IUI (which may be substitute'd`for the photo-cell 5I. Figure 8') to produce a pulse of current in the transformer winding 55, which is supplied to the circuit containing the lower winding of relay 98; dm'ng the interval between the pulses produced by rectifier 98, the rotor'may be considered in step with the, positive pulsesof thesine form voltage wave suppliedto the power amplierdi..

The relay 99 will not operate' by separate pulse from either the rectifier 98 or photo-cell lil I. But since-the motor is two pole, the rotor may be out of step several degreesrin which casethe relay would receive aiding pulses from both the rectifier 98 and the photo-cell lill and-would operate to open its contacts at l9'! which would include the resistance |02 inthe motor circuit momentarily in order to slow its speed sutiicient ly4 over a few revolutions to slip the rotor back in step with the supply current.

From the above description it is shown that the disk secured to the motor shaft will automatically keep in step with the current supply and that the other disk connected to the motor shaft will also generate voltage waves and pulses oi' current inexact phase relation and in synchronism with the received signals.

erating device, Figure 12, may be used to supply the line end frar'ne control frequencies at the vreceiver in a. similar manner to that shown in Figure 3 at the transmitter. When using this circuit. the picture signals developed in one horizontal line may be slightly out'. of adustment with the signals developed in the next following line, and to overcome this automatically I have provided a horizontal line |03, Figure-14, which is reproduced from-the permanent mark 3l at the transmitting tube Figure 1 and will occur in all picture changes and frames. From a point,- Just at the left of this horizontal mark |03, a'-

. This motor generator circuit or frequency genm inplannen-ree. ...solo

, principles involved.

Speed lead the picture time, the mark would move to the right causing light to enter the photo-cell IDS which would operate relay lill momentarily to include resistance |08 in the motor circuit,

thereby reducing the speed of motor. This feature has been disclosed in myY prior application.

. In the various circuits shown and described I have simplified the drawings by indicating the source of potential by a sign. Also I have omitted the heater filaments for the various tubes', but it is to be understood that such filaments are necessary.

The embodiments of the invention which have I been given herein are illustrations of how the various i'eatures may be accomplished and the It is to be understood that the invention contained herein is capable of embodiment in many other forms and adaptations,

without departing from the spirit of the invention and the scope of the appended claims.

This application is a division of application Serial Number 458,612, filed September 1'7, 1942, now

Patent No. 2,398,642, issued April 16, 1946.

lated on a carrier wave, a source of light. a rotary light valve driven by said motor to vary the intensity of a beam of light directed from said source toward the light valve, a source of direct y* I current supply, photo electric devices having suitable circuit arrangements actuated by the said variable intensity light beam to produce imfpulses of current from said source of direct cur-v polarity pulses of the alternating current.

Having thus described my invention, I claim:

i. In a motor control system, a source of alter nating current suppl?. a motor driven by altern atlng current from said source, automatic means under the control of the positive polarity pulses of alternating current from said source to change the speed of said motor i'or adjusting a point on the rotor relative to the positivepolarity pulses of the alternating current supply.

2. In a motor control system, a. source of alternatlng current supply, amotor driven by alterhating current from said' source, rotary. mechanism driven by said motor, means including said mechanism and for utilizing the positive polarity pulse of alternating current from said source to change the speed of said motor for adjusting the position of the said mechanism relative to the positive polarity pulses of the alternating current Supply.

3. In a motor control system, a source of alternating current'supply. `a motor driven by alternating current over a circuit extending from said' source, a resistor adapted to be included in said circuit, means including rotary mechanism driven by the said motor to produce spaced impulses of current, a, relay energized by the pOsitive polarity pulses of current from said source and from said spaced impulses to include said resistor in said circuit thereby changing the speed of the said motor for adjusting a point on said mechanism relative to the positive polarity pulses of the alternating current supply.

4. In a motor control system, a source of alterhating current supply, a motor driven by alterhating current from said source, rotary mechanism driven by the said motor, a source of direct current supply, photo electric devices having suitable circuit arrangements controlled by said mechanism to produce impulses of current from said source of direct current supply, a relay momentarily energized by the positive polarity pulses from the said alternating current Supply and from the impulses of current developed from the said direct current supply to alter the current supplied to said motor thereby changing the speed of the said motor to regulate a point on the said mechanism relative to the positive polarity pulses of the said alternating current supp 5. In a motor control system, a motor arranged to be driven by alternating current signals modu- 7. In a transmission system comprising a number of stations geographically separated by relatively great distances, each oi the said stations having movable members, a motor at each of the said stations to drive said members at correspond.

ing speeds of rotation from received alternating current signals, automatic means under the conn trol of said signals for making phase changes in any one of the said movable members comprising means for effecting a momentary change in the :speed of its drive motor to adjust the position ot "its movable member relative to the position of the' other movable members.

8. In a remote control system, a motor located gt a distant station, rotatable mechanism driven y said motor, a transmitter station, means at said\station to produce a carrier wave, means to transmit energy at the operating frequency of said motor modulated on said carrier wave, a receiver at said distant station wherein the modulated energy is developed and supplied to said motor, and automatic means under the control of the ni `ulated energy to facilitate the maintenance i, a point on said mechanism rotating through excertain arc relative to the positive polarity pulses of the operating frequency.

9. In a. remote-control system, a motor located at a distant station, a'source of direct current I supply, a generator comprising a plurality of electron tubes controlled by mechanism driven by said motor to produce alternating current from said direct current source, a transmitter station having means to produce a carrier wave, a receiver at said distant station wherein the modulated energy is developed and supplied to said motor, and means at saidv transmitter to change the frequency o f said energy to change the speed' of said motor. thereby regulating the frequency of alternating current delivered by said generator.

JOHN H. HOMRIGHOUS.

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

UNITED STATES PATENTS