US2375672A - Signature keyer and operator's indicator - Google Patents

Description

May 8, 1945.

4G. MALCNE SIGNATURE KEYER AND OPERATORS INDICATOR `Filed June 6, 1942 Malen/ mm los@ IIIIIO o mvnom. .n.6

` of`Morse code signals.

transmitting station.

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Patented May 8, .1945

UNITED STATE SIGNATURE KEYER AND orEnAToRs INDICATOR `George Malone, New York, N. Y., assignorto Radio Corporation Delaware of America, a corporation of Application June 6, 1942, Serial No. 446,093

` 7 claims. (o1. 177-380) This invention relates to signature keying. In communications work on radio channels, itis one of the requirements of the Federal Communications Commission that a 'signature 'code be sent out at periodic intervals for the purpose of showing the source of the intelligence which is radiated over a given channel. The signatures are customarily announced either orally or by means In United States Patent No. 2,134,562 which was granted October 25, 1938, to W. Kimmich, a signature keying device was shown and described. Such a keying device has been found particularly useful for keying the signatures of diierent relay stations in a multi` channel carrier wave system. In a simpliiied form, the device'of Kimmich may, of course, be used `for announcing the signature of asingle Inconnection with the operation of signature keyers generally, I'have found that it is desirable to provide intermittent operation of the motor which drives the codekeying cam. Such a motor needs to be run for only the brief time, say for about seconds, vin order tcannounce the signature, and then may be stopped for a periodof, say 14% minutes, more or less. During the time that the signature motor is not running, the channel is, of course, available for thetransmission `of traffic signals.

The sending `operator needs to be warned when his channel is to be occupied for signaturekeying. In order to utilize the channel at maximum eiciency, the operator needs to be again warned l one contact of which is preferably grounded. The

at the instant that his channel becomes available for the further transmission of messages;

Accordingly, it is an object of my invention to provide a system for automatic keying` oftransmitter station identication signals at periodic intervals. Y l

It is another object of my invention to provide indications at the sending station as to the times when signature keying takes place and the time when the communications channel is available :for the transmission of messages. w Other objects and advantages of my invention will be made apparent in the description to follow.

The description is accompanied by a drawing, in

which: l l

Fig. 1 represents in diagrammatical form a pre-` ferred arrangement for Icarrying out the inven- Fig. Zshows a modication.

Referring to Fig. l, I show'diagrammatically a signature code keyer unit l which includes a motor `driven cam 2 and a contact `assembly 3,

other contact leads `to a switching arrangement `which alternately selects each of two l signal sources for controlling an electronic keyerin a `conventional radio transmitter. The signature code keyer l is driven by motor 4. This motor derives its power from any suitable current source connected to` terminals 6.

A telegraph key is `indicated at l. This key, however, should be considered as merely symbolic of any conventional telegraph transmitting device; whether automatic or manual in its operationw In other Words, the traffic signal` keyer 1 may, if desired, be a tape-controlled Morse signal, or printer signal, sender, or it may be a facsimile transmitter suitable for sending `picture signals, or adevice forthe sending ci other types of intelligence signals.

My invention also includes a switch control device which may be continuously operated by a motor 8 connected to the source 6. This motor preferably has a worm 3 on its shaft. The worm meshes with a worm Wheel lill.` A cam Il is mounted on the same shaft with the worm wheel `Ill` and is continuously rotated.y The periphery.

`as tolshift the contacts i8 and `I9 from` engagement with their lower stationary contacts to their upper stationary contacts. In making this shift, the following circuit conditions are established:

Current from the source 6 is supplied through contacts I8 and 2| to the motor 4 for driving the unit l. Current is also supplied to a lamp 28, whichmay be of a suitable color; such as red, to indicate that the telegraph operator is to stop sending traic signals. i

The signature code keyer unit I duringoper ation becomes connected to the input bias conn trol circuit for an electronic keyer 25 whereby the signature code signals may be sent out over the radio channelwhich is in use. A biasing circuit for the keyer unit 25 lis indicated as includ-` ing abiasing source 26 and a resistor 2l.y` During The contact spring I8 has complementary contacts 20 and 2|.

shown) in that .keyer 425 will besuch as to render the tube conductive, las lis yvell understood by those skilled in the art. When the contacts 3 are broken, it is apparent that the ground potential will be removed from the grid ofthe electronic keyer tube and this tube will be biased to out off by a potential from the source 26.

When the cam follower `I2 has ridden complete ly` over the hump '24, conditions will be .restored for normal transmission of traffic signals. During the interval of 14 to 15 ensuing minutes, key T, or its equivalent, is connected `to the 'bia-sing circuit of the electronic keyer 25 and simultaneously a lamp circuit is closed through contacts 1:8 and '2U Lfor lighting the lamp 129 .to indicate to the `operator that he has a clearl channel. This lamp may be either green :or white 1i-n color if desired.

In order to give lthe operator :a few seconds of warning prior -to fthe breaking of his 'keying circuit, 'I have provided a hum-p :121i on the cam Il, .the configuration of which has two principal levels, or radii, above the principal peripheral radius. The cam follower l2 iis 'li'fted part'way by the Alower of the rtwo j-upraised portions -of the 'hump 221. I-n this first step `contacts 118 and 2li! are broken in order to extinguish the clearv lamp 23. Contacts 1S and 22 still remain closed however. Contact "22 is -o-f su-iiicientlyyielding structure so that it will follow contact AIB for only half 'of its total `rnovement. An arresting pin 3l! may be provided for restraining the Jcontact 2:2 from vfurther movement after fthe spring 19 'is lifted into :engagement with its companion contact '23. Such engagement `is,"of course, l'er'- ect'ive when the cam follower lf2 rides over vthe highest lportion of the hump 4211. A

lBy arranging the hump '2d to povide two stages of :switch control, the lamp '29 may be exitinguished at a moment 'appreciably prior to the lighting of lam-p Y28 and also before lbreaking the circuit of the trafiic signal keyer "1.

In accordance withthe modication shown in Fig. '2, the operator may be warned of the breaking of his keying circuit before this circuit v is actually broken, the warning Ysignal `loei'ng KVgiven i by switching off thelamp '29 and almost simultaneously 'lighting the lamp 28 atan instant, say

two or three seconds prior to the 'transfer Iof the i control of the -electronic lieyer 25 from the key 'I tothe signature code Ikeyer '-l.

In Fig. 2, vI show three cams 3l, '32 and 33 mounted for rotation on a single shaft which may be lcontinuously motor driven through any suitable reducing gear. The "hump 2id-a -on 'cam 3l is lof longer arc than the humps on v'cams'32 and "33. "Ihe cam follower rollers l2a vl'-,2fbahd 12e may all of them be simultaneously lowered to the minimum radius of the respective cams ments. It is a unit, the contacts of which are conveniently housed so as to be protected from dust and dirt. A snap action is incorporated into the design of the contact arrangement A very slight movement on the part of the cam follower roller is suiiicient to actuate the switch, either 'for .single-throw or `double-throw operation. i

The arrangement of parts as shown in Fig. 2 'will be readily understood in view of the complete circuit diagram of Fig. l. The modification of Fig. 2, however, consists in providing independent switch units 14| and 42 in place of the contact assembly, the contacts of which are labelled 88, 2B, and 21 in Fig. l. Thus the unit 4I contains contacts 18a, 20a, and 2Ia. which are used vexclusively for the control of the lamps 28 and 29. This control provides for extinguishing the lamp 29 substantially at the moment of lighting the-lamp 28. Due to the greater arcof the hump 2da on cam 3l in relation to the arcs subten'ded Vby the humps on cams A32. and 33, the

lamp 2.8 will become lighted ,Stor a brief {momen-t,

say about two Yor three seconds, prior to `the time interval which is occupied for signature keying. When .the switch units d2 Pand '4.3'areac1tuated, however, the motor 4 is caused ito drive the signature code keyer l. lThis function .is .obtained by the closing -of contacts .lband 2lb in the switch unit 12K/in response to the Vengat-gement of the hump on Cam 3.2 with its cam follower roller 1.21).

During the interval oi signature code keying A lby the .unit l the input .circuit for :the .electronic keyer 25 must be switched into .connection with .the 4contacts V3 of .the signature code keye-r l.. Simultaneously, the connection -.betweeny the tra-ffic keyer 1 and the electronic keyer 25 must be broken. As will readily be seen lfrom the details ofV .the double-throw . switch unit 4,3,` these oonditions are established when -contacts 19a' 1and 22a `break and contacts -Hla and 23amake.

Since the input circuit `for 1the electronic ,keyer Zii is :intimately .associated with high frequency apparatus, 'it .may be desirable to electrostatically shield this Icirc-uit from .the circuits whichlarefed from the power source 6. Accordingly, an electrostatic shield 44 may be interposed ybetween switch unit yI3 and other switch `units andelectrical circuit arrangements `of the corn-plete oombination. e

.Since corresponding parts in Figs, `:land 2 bear the same reference numerals and such numerals have subscript letters Aapplied in Fig. .2 :for ldistinguishing `their separate functions, Vit ,is believed that no vfurther Vdescription of Fig. 2 .is necessary; particularly, `where the complete circuit arrangement as shown in Fig. l may be readily understood as applicable to the modification shown in Fig. y2.

In view of the foregoing description, it will be understoodthat considerableutilityis to be found for my invention, due lto the reconomy of channel time as by indicating tothe :operator just when he `can use his key l, and just he should cease 'using it because such'use wouldfai'l in Vits purposes duringthe disconnection of the traffic signal keyer from the outgoing channel.

Various applications Iof my inventionv may be particular combination of elements or arrange` marking andspacing signals, a'motor for interi i mittently -driving said signature keyer, a traiiic i ing a major portion of the idle period of said signal keyer, acoinmunications circuit connect-,1`

able alternately to one andto the other of the two said keyers, `a pair of indicato-r devices each individually operable to4 denote predetermined and,` mutually exclusive times for signature keying and i for traffic signaling respectively, and continuously motor-driven switching means for supplying power during a predetermined time interval to said signature keyer motor and to that one of` said indicator devices which is associated therei with, said switching means being further operable to supply power to the other said indicator device and to connect said communications circuit to said trac signal keyer for a subsequent predetermined period.

2. The combination according to claim l and `including at least one cam and a cam follower through which said switching means Vis motor driven.

3. Apparatus for signature keying and for indicating the periodic use of a signature code keyer,

comprising said keyer, an intermittently operable signature keyermotor, a communications `channel, a trame signal keyer,'switching means includof operation of said signature keyer motor for indicating the lapse of said period.

4. In combination,` a signature code keyer, a motor for actuating said keyer intermittently, a

traine signal keying device, a keying circuit, a

cam-actuated switch for connecting said circuit alternately to said keyer and to said keying device,

a second cam-actuated switch for controlling the running and idle periods of said motor, an indicator lamp connectable by said switch to a given power source at least during the running periods of said motor, andasecond indicator lamp con-` nectableby said switch to said power source durmotor.

5. The combination according to claim 4 and including a plurality of `cams mounted on a common shaft, said cams constituting means for maintaining a predetermined cyclic phase relation i between the operation of said switches.

6; In combination', a signature code keyer; a

motor for actuating said keyer intermittently; a trafc signal keying device; a keying circuit; a switching arrangement comprising three units, A, B, and C, each individually controlledby a separatecam-f-ollower riding over the periphery of an appropriate continuously motor-driven cam, each of said cams being rotatable on a common shaft; and two indicating lamps; the conguration of` said cams being such that switch unit A is rst operatedto extinguish one lamp and to light the other, switch unit B is subsequently operated to close a` power supply circuit to said motor, switch unit C is operated substantially simultaneously with switch unit B to transfer the connection of said keying cir-cuit from said traic signal keying device to said signature code keyer, and the three said switch units are operated in the reverse direction substantially simultaneously.

7, Apparatus for periodically actuating a signachannel, comprising continuously motor-.driven cam-actuated switching means for producing circuit -closures which connect said keyer to said radio channel during recurring signature keying periods, a traine signal keyer connectable by said v 4switching means to said channel during intervening periods, a pairof indicator lamps having individual lighting circuits said switching means

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