US1721368A - Calling-up device for wireless communication - Google Patents

Description

July 16, 1929. G. c. BEDDINGTON 1.7213

CALLING UP DEVICE FOR WIRELESS COMMUNICATION Filed July 15, 1925 3 Sheets-Sheet l flue/I787" Guy C aade Zak 15y??? A Ew July 1 1929- G. c. BEDDINGTON 172L368 CALLING UP DEVICE FOR WIRELESS CQMMUNIGA'I'IQ Filed July 15, 1925 3 Sheets-Sheet 2 Patented July 16, 1929.

GUY CLAI IDE BEDDINGTON, OF PENN, ENGLAND; EDWARD HENRY LIONEL'BEDDING- TON AND RONALD HERBERT SIMON WALEY EXECUTOBS F SAID GUY CLAUDE BEDDINGTON, -DECEASED.

CALLING-Ill- ;onvrcn ron WIRELESS COMMUNICATION. i

Application filed July '15, 1925', Serial No. 43,835, and in Great Britain July 31, 1924.

The invention relates to calling-up devices for wireless receivers and consists'in an arrangement by means of'which the device is actuated by the reception of one ormore definite wave frequencies, either simultaneously or consecutively, as prearranged.

According to the present invention a double grid valve or a plurality o'f' valves which, for the purpose of distinction, will be called key valves is interposed between the tuned circuit or circuits receiving the calling-up signals and a valve having a relay device and battery in its anode circuit in V such manner that the eflective resistance of the relay valve andconsequently the current in its anode circuit is varied suliiciently to operate the relay only uponthe receipt of waves of the appropriate frequency or fre- A relaylquencies. If two or more frequencies are used in calling up it'may be arranged for the device to be operative only when these frequencies are simultaneously received or for the consecutive reception within defined time limits of the several frequencies.

In one arrangement according to the present invention the calling up signals are received simultaneously in two tuned circuits respectively connected with two grids in. the same valve, the anode of this'double grid key valve being connected over a battery to the grid of a second valve,'the grid potential of which is such that normally an anode current through the valve traverses a a The negative potential applied" to the grids of the .key valve are adjusted so that when no signals are being 'received its filament to anode path is virtually of infinite resistance and when only one of the set of signal waves is received there is no pract1cal elfect upon the second or relay valve, but when both waves are received simultaneously, the combined effect of positive halfcycles is to make the key valve partially conductive and negative potential .is applied from the; battery to the grid of the relay valve onwhich it accumulates faster than it can leak away, thus reducing the current in the relay and thereby operatingthe calling instrument. I I t A condenser may be placed so as toassist the action and to holdthe negative charge induced during the reception of the positive half-cycles on the grid of the relay'valve for a considerable period of time after the signal frequency has ceased and a high resistance may be inserted between the anode of the key valve. and the grid of the relay valve to retard this accumulation, in order to prevent accidental calling up.

In another arrangement in which the calling-up signals are received consecutively on two'tuned circuits, four valves are used. One tuned coil is connected with the grid of the first valve and the anode of this valve is connected over a battery with the grid of the second valve.v During the reception of the waves as explained above and, if a suitablecondenser is used, for a period of time afterwards, this battery causes negative potential to accumulate in the grid of the second valve, thus increasing the resistance of the anodepath of thesecond valve which is usually of some thousands of ohms to a value that is virtually. infinite. The third valve is provided with two grids, one of which is connected with the second tuned coil and the other over a battery with the anode of the secondvalve. The anode'of the 7 third valve is connected over a batterywith H80 the grid of a fourth valve in the anode circuit of which a relay is energized by the normally flowing anode current. v r

The potential applied to the grid of the second valve is suchthat when no signals are being received, the anode current in this valve applies a potential to one grid of, the third valve which renders this valve ineffective in its action on the fourth valve, andv consequently on the normal relay current, even when signals are being received by the tuned coil associated with the other grid of thethirdvalve. v i When, however, signals are received bythe tuned coil associated with the first valve, a

negative potential accumulates on the grid valve, thus reducing the current through it and thus operating the relay and hence the calling instrument and continuing to do so after signals have ceased, as long as the con denser holds a sufficient negative potential on the grid of the fourth valve.

.In another arrangement according to the present invention the anode or anodes of one or more key. valves are connected over batteries with the grid of a valve in the anode circuit of which is a battery and a relay.

The normal potential on the grids of the key. valves being approximately zero, the anodefbatteriesassociated with the key. valves are of such voltages that any one of them alone impresses on the grid of the relay valve a sufiicient negative potential so that no anode current normally passes through the relay valve, or at any rate noanode current su'fiicient to operate therelay.

Matters are so'arranged that in-coming signals cause negativepotentials to accumulate on the grids of the key valves faster than they can leak away, thus making the resistance of their filament to anode pathsvery great, and hence removing the paralyzing negative potential on the grid of the relay valve, which valve therefore passes suflicient anode current to operate the relay. V

The accompanying drawings showv diagrammatically in Figs. 1 and 2 circuitarrangements according to the invention, Fig- 3 is a diagram showing the potentials ap plied to the grids of the valves employed in the circuit arrangements ofFig. 2; Fig. 4 is a diagram of connections ofanother modification,.Fig. 5a diagram of grid potentials ,thereof; and Figs. 6 and 7 are diagrams of circuits emb dyingfurther' modifications. 7

Referring toFig; 1, in which the calling device is operated bywavesof different he quencles recelved simultaneously, L and L are oscillating coils tuned respectively to the different frequencies to be I received and which may be coupled to suitable inductances 1n, an aerial circuit. Alternatively, these coils mayform part of low frequency circuits associated with detectors,' the latter being associated with circuits tuned to the operating frequencies.

" The coils L L are connected respectively,

i hgfidSGK G? of a key valve] V of which. F 'repre'sentsthe filament and A? 'theanode connected over a resistance rand battery B to the grid G of a relay valve.

V The anode A of the valve V is in series with a call up relay R and battery D. The filaments F F may be supplied with heating current by a common battery E.

A condenser C is inserted as shown across the grid G and the negative terminals of batteries D and E. The potentials applied to the grids G G are adjusted by the bat- I teries b b I The negative potentials appliedto the grids G G are adjusted so as to beat or near to the points of origin of their"charac- .teristic curves, the anode path of the valve V offering practically an infinite resistance, while the potential of the grid Gtis adjusted so that a normal current flows through the relay R under no signal conditions.

- When signals are received by the coils L L the negative half-cycles have no effect, butthe valve becomes partially conducting during the positive half-cycles and the, bat tery 'B supplie's negative potential to grid G of valve V? where it accumulates, thus reducing the anode current and operating relay R to energize the calling device, if the I change is sufficient and maintained fora suflicient length of time for the. cumulative effect to come into play. .The condenser C serves to hold the charge in the, grid and to. assist the working. It is not essential butif it issufliciently large. may be effective to 2 operateswhen two setsof signal waves are received consecutively.

The tuned coil L .iseconne'cted to the grid G of valve V 'The anode plate A is connected over the resistance r and battery B to the grid G? of valve V Valve V? has twogrids-G Gr offwhic'h G is connected over battery B to the anode A of valveV and G is connected with the tuned coilfLfi. The anode A of .valve V is connectedjover the resistance r? and battery B with 'grid G of valve V, the anode A of which is in series With the relay R. Condensers" (1 ,0 are inserted respectively across grids G and G? and the negative terminal connection of" batteriesEand D.

In Fig. 3 curves (bfshow thefpotenti'als appliedtothe grids ofl V anew plot ted against the resulting negative potentials effective on the grids of V and V Curve (0) shows the potential applied to the grid of V that is associated with a tuned circuit plotted against the resultant effective negative potential on the grid of V under conditions such that the grid of V which is associated with V is at approximately zero potential with respect to the negative end of the filament of V. Curve ((Z) .shows the negative potentials applied to the grid of V plotted against the anode current passing through the latter and the relay.

The points marked X on the characteristic curves indicate the normal potentials of the grids.

Under no signal conditions the normal current flows through relay R since the valve V is normally conductive.

Valve V is also normally conductive and imparts sufiicient negative potential to the grid G so that this valve is rendered inoperative even when signals are received by the coil L The valve V becomes partially conductive during the positive half-cycles of the waves received by the coil L and negative potential accumulates on the grid Gr of valve V introducing a practically infinite resistance in the anode path of this valve and eliminating the negative potential previously applied to the grid G -The negative potential on the grid of V is held there by a condenser C for a given time after the connection of the frequency to which L is tuned, so that if signals are received within that time of the frequency to which L is tuned during positive halfcyces C will become partially conductive and hence negative potential accumulates on the grid of V therefore reduced, the reduction serving to operate the relay R and hence a call up device which will continue to operate after all signals have ceased if G which is not, however, essential, be sufliciently large.

In Fig. 4. a circuit arrangement according to the invention is shown diagrammatically. In Fig. 5 curve (a) shows the potentials applied to the grids of V V V plotted against the resulting negative potentials impressed on the grids of V V V by the batteries B B B Curve (6) shows the potentials impressed on the grids of I, V V by the batteries B B", B plotted against the resulting negative potentials impressed on the grid of the relay valve V by the batteries B B B. i Curve (0) shows the characteristic grid voltage anode current curve of the valve V The normal grid potentials are indicated at the points X. Normally valves V V V are virtually non-conducting, valves V, V and V are partially conductive and the relay valve V either non-conductive or insufficiepgty so to permit the operation of the relay During reception of, the frequency to The anode current of V is which L is tuned negative half-cycles are v ineffective, whereas positive half-cycles cause negative potential to build upon the grid of V faster than it can leak away. V therefore becomes non-conductive and shuts off the negative potential impressedon the grid of V by the battery 13* "for as long as the frequency continues and for a period of time afterwards if condenser C be of a suitable capacity.

If during this time the frequency to which L is tuned be received similarly negative potential will accumulate on the grid of V thus shutting off the negative potentialimpressed on the grid of V by B. This state of affairs will continue, after the frequency to which L is tuned has ceased, for a period of time depending upon the capacity of condenser. G

And similarly, if the frequency to which L is tuned be received while the valves V and V are still non-conductive, the resulting negative potential accumulating on the grid of V will shut off the negative potential impressed on the grid of the relay valve V by the battery B".

Hence, if the three frequencies, to which L L and L are tuned, are received consecutively within a period of time determined by the capacities of the condensers C C and C then the relay valve V will become sufficiently conductive to operate the relay R. i I

If th e'condensers C C C are omitted or small in capacity, then the three desired frequencies will have to be received simultaneously in order to operate the relay.

It. is plain that if only two frequencies are used then V and V may be omitted, and if one frequency only, valves V and V may be omitted also, but if more than three calling-up frequencies are used, more valves may be added similarly.

The high resistances 1' 1 1 may be used to introduce a relay action to prevent accidental calling up, but they are not essential.

It is not essential that the valves in'front of the key valves (e. valve V in Fig. 1,

valves V V in Fig. 2 and valves V V V in Fig. 4) should be high frequency rectifying valves. They may be adaptedv to rectify low frequency currents produced by rectifyingvalves associated with the tuned circuits (e; g. L L L and these latter valves may also be preceded or followed by high or low frequency amplifying stages.

In the circuit of Fig. 6 the action oflthe key valves V W, V is substantially the same as that of thekey valves V V V in Fig. 4, except thatthese valves rectify not high frequency currents directly, but the low frequency currents produced by the rectifying of the high frequency currents by the detector valves V V V High frequency currents induced conseccharacteristic curves.

utively in the inductances L L L are consecutively amplified by the valves V V", V and consecutively rectified by the valves V V1 V being handed on by the high frequency transformers T T T The valves V V, V may be adjusted to rectify by means of the grid-batteries b 6 I), or by other means. The resulting low frequency potentials across the primaries of the low frequency transformers T T, T are stepped up consecutively by these transformers and are applied to the grids of the valves V V V which valves are adjusted by means of the grid-batteries 6 79 b to be operating on the point of origin of their Thus, as high frequency currents are consecutively induced in the inductances L L L negative potentials consecutively accumulate in the grids of valves V V V owing to the action of the batteries B B 1 and thus the valves V, V V are consecutively made nonconducting, andremain so for periods of time depending upon the capacity of the condensers C C C As soon as all three valves V V V are made non-conducting, the negative potential normally impressed upon the grid of the relay valve V by the battery B is shutoff, thus allowing anode current to flow through the valve V and therefore operating the relay R for as long as the valves V V V remain non-conducting. The resistances r 1, r are not essential but may be used to prevent accidental calling up due to atmospherics.

Furthermore, by using tuned low frequency transformers, one or more predetermined high frequencies may be used in conjunction with one or more predetermined modulation frequencies. Thus, in the circuit of Fig. 7 all. the components are analogous to those similarly indicated in Fig. 6, but instead of the key valves V V V being operated by the rectified currents due to the rectification of three different high frequency currents, these valves are operated consecutively by the three low frequencies to which the low frequency transformers T T T are tuned, these three low frequencies being modulations consecutively impr ssed upon the high frequency to which L is tuned.

The system is capable of modification for usewith any amount of key valves operated by as many high frequency or modulation frequency currents as are desired, and by reducing the values of the capacities of the condensers in the anode circuits of the key valves, as well as by removing the high resistances in those anode circuits the key valves can be made to operate with little or no lag so that the relay in each case may be used to actuate a recording device.

Having thus described the nature of the said invention and the best means I know valve sufiiciently to cause operation of the.

relay only upon. the reception of calling-up signals to which said circuit means is tuned.

2. A calling-up device for wireless reception comprising receiving circuit means tuned to receive the calling-up signals, a

- relay valve having a relay device in its anode circuit and means for normally controlling the conductivity of said valve to the flow of current in its anode circuit, and key valve means comprising a plurality of control electrodes interposed between said tuned circuit means and said relay valve and operative to vary the resistance of said relay valve and thereby cause operation of the relay only upon the reception of calling-up signals of a frequency appropriate to said tuned receiving circuit means.

3. A calling-up device for wireless reception comprising circuit means tuned to receive the calling-up signals, a relay valve having a relay and a source of current in its anode circuit, means normally controlling the grid potential in said relay'valve, thereby governing the flow of current in its anode circuit and through said relay, and key valve means comprising a plurality of control electrodes interposed between said tuned circuit means and said relay valve and operative to alter the grid potential of said relay valve whereby the anode current in the latter is varied sufficiently to cause operation of the relay only upon the reception of calling-up signals to which said circuit means is tuned.

4. A calling-up device for wireless reception comprising circuit means tuned to re ceive the calling up signals, a valve having a relay and a source of current in its anode circuit, and key valve means the conductivity of which is controlled by the reception of calling-up signals to which said circuit means is tuned, said key valve means comprising a plurality of control electrodes interposed between said tuned circuit means and said relay valve and being operative to alter the grid potential of said relay valve whereby the anode current in the latter is varied sufiiciently to cause operation of the relay only upon reception of calling-up signals to which said circuit means is tuned.

5. A calling up device for wireless reception comprising circuit means tuned to receive the calling up signals, a three-electrode valve having a relay device in its anode cirwit, and valve means comprising a plurality of control electrodes interposed between said tuned circuit means and said three-electrode relay Valve and operatiye upon the receipt of calling up signals to which the said circuit means are tuned to alter the grid potential of the three-electrode relay valve,

whereby the anode current of the latter is changed sufficiently to cause operation of the relay.

' In testimony whereof I have signed my name to this specification.

GUY CLAUDE BEDDINGTON.

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