US1679852A - Synchronizing system - Google Patents

Description

Aug.. 7, 1928;

A. F. CONNERY SYNCHRONIZING SYSTEM Filed oct. 22, 192e 2 sheets-sheet l Luo IOFUUEOU P05460 ,(JU P7350" vm Dujnv @UJaH 24mm u Nv-m u HLO N. Nm Tal E B .uOJU wv.u(.r.1 JMM 0P3D L wa|h m o 0 ,u sul o f ill Aug. 7, 192s. 1,679,852

' A. F. coNNERY SYNGHRONIZING SYSTEH Filed oct. 22. 192s 2 sheets-sheet 2 Sifweuto @11 r www?" WMM I lll) elfi

Patented Aug. 7, 1928.

UNITED STATES PATENT OFFICE.

ALDER F. CONNERY, OF JAMAICA., NEW YORK, ASSIGNOR TO COMMERCIAL CABLE COM- PANY, OF NEW YORK, N. Y., A GORPORATON OF NEW YORK.

SYNCHRONIZING SYSTEM.

Application tiled. October 22, 1926.

My invention relates to synchronizing systems and refers more particularly to synchronous telegraph systems used in conneci tion with conductors ot high electrostatic capacity, such as for example long submarine cables.

The principal object contemplated by my invention comprises providing an improved means tor utilizing distorted signals such as, tor example, those received over long cables, tor the purpose of synchronizing locally generated or reformed signals therewith.

Heretofore the synchronizing means used in connection with ocean cables have been very similar to the means used on land lines. rFliese means of controlling synchronism iront the received signals while satisfactory `for land line apparatus are not entirely satis factory when used with apparatus on ocean cables due to the peculiar signal distortion caused by the high electrostatic capacity ot the conductor.

In the unit or niultiple-unit code which is in general use on ocean cables the various letters are termed by combinations ot positive and negative impulses and the space between letters is indicated by an earthing or aero interval. The instant of operation olf the receiving relays by a signal is inl'luenced to a considerable degree by the character oll the preceding signal. The arrival ot a positive impulse, :tor example, will occur at certain tinie it the preceding impulse was Zero, but will occur a little later it the preceding impulse was negative. rlChis ellect is well known to cable operators and engineers.

Synchronizing systems heretofore used in conjunction with telegraph systems employed on ocean cables have been controlled by the instant of arrival of either dots or dashes or both. No account has been taken oil the eltcct of the preceding signal on the signal :troni which correction is obtained. In my .improved system I maintain the reformed or locally generated signals in synchronisin `with the received signals by means oi received signals which are preceded by a signal ot predetermined character only.` Thus the instant of operation of the controlling mechanism is maintained constant and more reliable synchronism is thereby attained.

In the drawings which accompany and torni a part of this specilication, and in which like reference numerals designate corresponding parts throughout:

serial No. 143,471.

Fig. l illustrates diagrammat-ically the operating tune sequence oit the various elements ot my system with reference to the current impulses necessary to transmit a sample word.

2 illustrates'diagrammatically an embodiment ot my system adapted for. use as a cable repeater.

Jreferring now to Fig. l, line l shows diagrammati 'ally the impulses forming the word Canadians as transmitted into the ca ble. Line 9. shows the shape of the received signals, while line graphically represents the operation of the receiving relays by the received signals, from which it will be seen that a dot or Vdash tollowinftv a space will cause the relays to operate earlier than il the d ot or dash had followed a signal of oppo- "site polarity, as for example, the lirst and last units or the letter' C shown at a and d line 3 are longer than the 2nd and 3rd units shown at and c on the same line. In other words the first and last units ot each letter always have a tendency to run into the zero signal. l

Referring now particularly to Fig. 2, I will describe one embodiment of my invention as applicable to a cable repeater. Signals are received over cable l, which is bale anced by the usual artilcial cable ll, and operate the moving coil 2 which in turn causes contact l t slide over the surface et the revolving drum Ll. rllhe central portion oilfv the druin l is insulated as shown and contact 3 normally rests on. the insulated portion when the space or zero signal is received. lhen either a dot or dash is received contact 3 lnoves from the insulated portion oil drum fl to either one or the other ot the metallic `portions of the drum. Such receiving mech anism is well known in the art and needs no further explanation. When a dot is received mal-:e relay 5 and dot relay G will be operated, and when a dash is received make relay 5 and dash relay 7 will be operated. Malte relay 5 operates when either a dot or dash is received while dot relay 6 only operates `when a dot is received and dash relay 7 only opcrates in receipt of a dash.

A distributor comprising series ot cams 8, 9, l0, ll and l2 mounted in liXed angular relationship to each other on a shait is adapted to be driven by a synchronous niotor. This motor which is not shown because its use is obvious to those skilled in the art,

(ill

is driven in the usual manner by contacts made by the vibrations of the tuning fork 13. The frequency of the fork 13 is so adjusted that the contacts of cams 8, 9, 10, 11 and 12 will when no cuirent flows through the magnet 14 make slightly fewer contacts than the number of signal units ieceived over the cable. Vhen relay 15 closes its contact, magnet 14 is energized and the action of magnet 14 on the fork will cause the fork to reduce its amplitude and thus increase its frequency, .thus causing the contacts operated by cams 8, 9, 10, 11 and 12 to make slightly more contacts than the number of signal units received over the cable.

Relays 15, 17, 21 and'22 are all polarized relays and are adjusted so that their armatact current will How through the armature yno ofrelay 5, the armature of relay 16, contacts of cutout relay 17, cam contacts S or F of cams 11 and 12 respectively and thence through windings 1S or 19 of relay 15 to ground. If eamcoiitact S is closed when the impulse through the break relays 5v and 16 occurs, the armature ofi-clay 15 will be thrown to the left as viewed in Fig. 2 and current through magnet 14 will be interrupted. The fork will therefore slow down and the c: ni contacts controlled thereby wil make at a slower rate than the frequency of the received signal units. If, however, cani contact F is elo-sed when t-he impulse through the break relays 5 and 16 ccurs the armature of relay 15 will be thrown to .the right as viewed .in Fig. 2 and magnet 14 will be energized to cause the fork to make contacts at a higher rate and thus cause the cams to Imake and break their contacts at a faster rate than the frequency of the received signal units.

If Athe armature of relay 17 is held in a Vclosed position the apparatus just described willmaintain synclironism, but there will be considerable phase hunting caused by the variant distortion of the received signals as is tlie case in present systems which take no account of the character ofthe signal preceding the received signal. The purpose of relay 17 is to prevent signals other than those preceded by a signal of definite predetermined character from having any effect on synchronism by .opening up the circuit from the break relay 16 at the proper predetermined intervals.

In the particular embodiment of the in- .vention being described the .apparatus and so designed that the only opportunity A['or synchronism correction is at the start. of the first dot or dash after a space. 'lo this cnil relay 17 opens after the lirst signal unit ot ay letter is selected, and the correction system is thus rendered inoperative until a zero signal is again selected. Referring to Fig. 2 the means which operate relay 17 will now be particularly described. lVhcn a dot. is received dot relay 6 operates, cam contact 8 closes and current flows from positive battery through contacts of relay 6, through winding 2t) of transmitting relay 2l and through winding 23 of relay 17 and cam Contact 8 to ground. The arn'iatures ol re lays 21 and 17 will be thrown to the right as viewed in Fig. 2, and an impulse will be transmitted from battery 5t) to cable lt). Cam contact 9 closes at the saine instant as cani contact S. Then cam contact 9 is closed current lows through winding 21- ef relay 17 and tends to but does not throw thc armature of relay 17 to the left as viewed in Fig. 2. 1f a dash is received relay 7 will be operated and relays 22 and 17 will be thrown to the right as viewed in the ligure and a dash will be transmitted to cable L10. 1f any dots or dashes are now received the impulse generated by relays 5 and 16 at the .start of each dot or dash will not get through to relay because the circuit is open at the contacts of relay 17. If now a` zero .signal is received, relays 6 and 7 will not be operated, no current will flow through winding 23 of relay 17 and the armature of relay 17 will be thrown to the left by the weak currentexisting in'winding 2-lthereof, due to the closed condition of cam contact 7. The synchronism correcting circuit is now ready to respond to the next dot or dash received. lt, for example, the next signal al'ter a space or zero signal is a dot relays 5 and 6 will operate, relay 5 will cause relay 16 to operate and the short impulse of current through the armature of relay 16 will pass through the contacts of relay 17 and will throw the armature of relay 15 either right or lett depending upon which of the contacts S or F, were at that instant closed. lVhen cani S closes, relays 17 will open the synchronizing circuit.

The purpose of the contact operated by cam 10 is to restore transmitting relays 21 and 22 to normal just. before cach signal is selected and to thus give a short earthing interval on cable L10 between each dot or dash.

Referring now again to Fig. l, line Al shows the relative time sequence of the iinpulse through the armature of break relay 16. The operation of cutout relay 17 as shown on line 5 permits some of the impulses from the break relay 16 to pass and prevents others. The cutout relay 17 is so connected that it opens the circuit cach time a dot or lll) l li

dash is selected and closes the circuit every time a Zero or space impulse is selected, thus the only opportunity for the correction of synchronism is at the start oft the iirst dot or dash artter a space.

lt will be obvious that the impulses from the break relay 16 which are permitted to pass the cutout relay 17, all fall on the F corrector contact et the distributor as shown by lines G and '7. All these impulses theretore lreep the corrector relay armature in the right hand position as shown in Fig. 2 and current flows in the corrector magnet la as shown on line 8, and continues to flow nntil the distributor is in phase with the frequency oit the received signals.

lllhile l have described but one embodiment of my invention and that with par ticular reference to a cable repeater it is to be thoroughly understood that my device. not limited to such use, but may be used in numerous electrical systems requiring synchronism between received signals and those locally generated for further use.

Having thus completely described my invent-ich what I claim is:

l. A three-element code synchronizing system con'iprising, signal receiving means, means co-operative with said receiving` means :tor generating potentially available signals in approximate synchronism with the received signals, and means tor correcting the synchronism, said means being operable only by received signals which are preceded by a signal ot predetermined invariable character.

2. A three-element code synchronizing system comprising, signal receiving means, ineens co-operative with said receiving` means tor generating signals which are potentially available iter further use, means l'or maintaining said generated signals in synchronism with the received signals, said means being operated by received signals which are preceded by a signal of definite invariable character only.

3. A three-element code synchronizing system comprising, signal receiving means, means eo-operative with said receiving means for generating signals which are potentially available for further use, and means operated only by a received signal which is preceded by a signal of predetermined invariable character for maintaining said generated signals in synchronism with the received signals.

d. A threeelement cede synchronizing system comprising, means :tor receiving signals, means coopera-tive with said receiving means for generating potentially available signals appronin'iately in synchronism with the received signals. and means oper able only by received signals which are preceded by a signal ot predetermined invariable character for bringing said generated signals into iull synchronism with said received signals.

5. A three-element code synchronizing system comprising, signal receiving means,I

means co-operative with said receiving means for generating signals which are potentially available 'tor further use and means operated only by a received signal which is preceded by a Zero signal formain taining said generated signals in synchronisin with the received signals.

6. A three-element code synchronizing system comprising, signal receiving means, means cooperative With said receiving means for generating signals which are potentially available for further use, rotary means controlled by vibratory means for approximately synchronizing said generated signals with the received signals, and means controlling said Vibratory means and operated only by received signals which are preceded by a signal of detinitc invariable character 'tor bringing said generated signals into full synchronism with said received signals.

ALDER l?. CONNERY.

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