US2251958A - Telephony - Google Patents
Telephony Download PDFInfo
- Publication number
- US2251958A US2251958A US184089A US18408938A US2251958A US 2251958 A US2251958 A US 2251958A US 184089 A US184089 A US 184089A US 18408938 A US18408938 A US 18408938A US 2251958 A US2251958 A US 2251958A
- Authority
- US
- United States
- Prior art keywords
- circuit
- signal
- frequency
- currents
- telephony
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q1/00—Details of selecting apparatus or arrangements
- H04Q1/18—Electrical details
- H04Q1/30—Signalling arrangements; Manipulation of signalling currents
- H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
- H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
- H04Q1/446—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using one signalling frequency
- H04Q1/4465—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using one signalling frequency the same frequency being used for all signalling information, e.g. A.C. nr.9 system
Definitions
- Our invention relates to telephone receiving apparatus, and more particularly to a combined receiving, amplifying. and signalling device.
- signals such as ringing -currents and selection impulses.
- carrier-wave telephony such signals are modulated on the carrier-wave used to transmit the speech current, and after being demodulated and amplified, are supplied to a socalled signal receiver, and in low-frequency line telephony the signal receiver is connected directly to the line.
- the signal receiver must respond only to signal currents and not to speech currents of the same frequency, it. is the usual practice to utilize the diflerence in amplitude or in duration between the signal currents and the speech currents.
- signal receivers operating on this principle are complicated and expensive.
- the object of the present invention is to overcome the above difliculties and to provide a very simple and inexpensive receiving apparatus.
- I provide in the input circuit of the amplifier an oscillatory circuit which is tuned to the signal frequency, and is connected to a rectifier and a resistance.
- the signal currents produce across this resistance a voltage drop which controls the grid voltage, and thus the anode current of the amplifying tube of the amplifi'er, to thereby energize a relay included in the anode circuit and controlling the signal current circuit.
- Figure 1 is a schematic view of a portion of a telephone receiving apparatus embodying the invention
- I Fig. 2 is a schematic diagram of an apparatus according to another embodiment of the invention.
- the receiver-amplifier illustrated in Fig. 1 comprises an input transformer I having a pri mary winding M, which in the case of lowrfrequency telephony is connected directly to a transmission line, and in the case of carrier-wave telephony is connected through a demodulator and the required filters.
- I input transformer
- M pri mary winding
- carrier-wave telephony is connected through a demodulator and the required filters.
- connections are Germany January 29,1937 2 Claims. (cl. 179-84) well known in the art further illustration or description of the same is believed unnecessary.
- Transformer I has a secondary winding l5 connected in the grid circuit of an amplifying tube 3, and for this purpose has one end connected directly to the grid H and its other end connected through a rectifier 6 and a battery l2 to the cathode l3.
- Tube 3 has a plate I6 connected to one end of the primary winding ll of an output transformer 2, the other end of winding ll being connected through a condenser lit to a cathode l3.
- a control relay 9 having a normallyclosed contact adapted to control a signal current circuit l0 has one end of its coil connected to a point between winding H and condenser ll,
- I connect across secondary winding IS a series-parallel circuit arrangement comprising a resistance 4 and having two parallel branches, one branch being an oscillatory circuit 5 comprising a. condenser l9 and an impedancelll, and the other comprising a condenser 8 and a resistance I.
- the incoming signal currents produce an alternating voltage across circuit 5, which voltage is rectified by rectifier 6, so that a direct voltage is set up across resistance 1 and condenser 8.
- This direct voltage changes the bias of grid II, to thereby decrease the plate current of the tube and cause contact 2
- the circuit 5 will have a less sharp resonance curve for the signal currents.
- the magnetic induction will be The above is of course very, important because a i is makes it necessary to employ-special measures for maintaining either the natural frequency of circuit 5 or the signal frequency, constant, while,
- relay 9 might respond to the speech currents.
- FIG. 2 The apparatus shownjn Figure 2 is similar to that of Figure 1, and operates. in the same man'- ner. However, in Fig. 2 the oscillatory'circuit frequency, a rectifier, and a resistance.
- condenser I9 and impedance 2!] are connected in series across winding 14, and rectifier 6 is connected between a tap 22 on impedance 20, and a point 23 between windings l5 and resistance 1 and condenser 8;
- a telephony receiving apparatus comprising a low frequency amplifier including a grid-controlled amplifier tube, said amplifier having a grid circuit to which are supplied the received speech frequency band and signal currents of a .2.
- a telephonyv receiving apparatus comprising a .-low-'frequency amplifier including a grid-controlled amplifier tube, said amplifier having a grid circuit tdwhich are supplied the received speech fr eque-ncy bands and signal currents of a 'frequency within the speech-frequency band and of amplitudes which are large relative to those of the speech currents, and an output circuit adapted to be connected to utilizationv means for the amplifiedspeecn current; controlling means in said output circuit tocontrol a signal circuit, said controlling means being controlled by the anode current of said tube, and means in said grid circuit and associated with the grid of said tube to change the grid voltage when signal currents are being supplied, said latter means comprising a rectifier, a resistance, and an oscillatory circuit 1 tuned to the signal frequency and includinga coil having an iron core.
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Amplifiers (AREA)
- Devices For Supply Of Signal Current (AREA)
Description
1941- 'r. s. SKILLMAN z-rrm. 2,251,958
TELEPHONY Filed Jan. 8, 1938 Patented Aug. 12, 1941 ITELEP HONY v Thomas Samuel Skillman, Jan Willem Baurdoux,
' Y and Mathias van de Beck, Eindlioven, Netherlands, assignors, by memo assignments. to Hartford National Bank and Trust Company,
\ l Hartford, Court, as trustee Application January 8, 1938, Serial No.
Our invention relates to telephone receiving apparatus, and more particularly to a combined receiving, amplifying. and signalling device.
In low-frequency telephony, as well as in carrier-wave telephony over wires, it is well known to transmit in addition to the speech currents,
signals such as ringing -currents and selection impulses. In carrier-wave telephony such signals are modulated on the carrier-wave used to transmit the speech current, and after being demodulated and amplified, are supplied to a socalled signal receiver, and in low-frequency line telephony the signal receiver is connected directly to the line. As the signal receiver must respond only to signal currents and not to speech currents of the same frequency, it. is the usual practice to utilize the diflerence in amplitude or in duration between the signal currents and the speech currents. However, signal receivers operating on this principle are complicated and expensive.
The object of the present invention is to overcome the above difliculties and to provide a very simple and inexpensive receiving apparatus.
In accordance with the invention, which utilizes the fact that an amplifier is always present in both low-frequency and carrier-wave telephony receiving apparatus for amplifying speech currents, I provide in the input circuit of the amplifier an oscillatory circuit which is tuned to the signal frequency, and is connected to a rectifier and a resistance. The signal currents produce across this resistance a voltage drop which controls the grid voltage, and thus the anode current of the amplifying tube of the amplifi'er, to thereby energize a relay included in the anode circuit and controlling the signal current circuit.
In order that the invention may be clearly understood and readily carried into effect, I shall describe the same in more detail with reference to the accompanying drawing, in which:
Figure 1 is a schematic view of a portion of a telephone receiving apparatus embodying the invention; and I Fig. 2 is a schematic diagram of an apparatus according to another embodiment of the invention.
The receiver-amplifier illustrated in Fig. 1 comprises an input transformer I having a pri mary winding M, which in the case of lowrfrequency telephony is connected directly to a transmission line, and in the case of carrier-wave telephony is connected through a demodulator and the required filters. As such connections are Germany January 29,1937 2 Claims. (cl. 179-84) well known in the art further illustration or description of the same is believed unnecessary.
Transformer I has a secondary winding l5 connected in the grid circuit of an amplifying tube 3, and for this purpose has one end connected directly to the grid H and its other end connected through a rectifier 6 and a battery l2 to the cathode l3.
Tube 3 has a plate I6 connected to one end of the primary winding ll of an output transformer 2, the other end of winding ll being connected through a condenser lit to a cathode l3. A control relay 9 having a normallyclosed contact adapted to control a signal current circuit l0 has one end of its coil connected to a point between winding H and condenser ll,
and its other end connected to the positive side of a plate current supply (not shown).
In accordance with the invention, I connect across secondary winding IS a series-parallel circuit arrangement comprising a resistance 4 and having two parallel branches, one branch being an oscillatory circuit 5 comprising a. condenser l9 and an impedancelll, and the other comprising a condenser 8 and a resistance I. The incoming signal currents produce an alternating voltage across circuit 5, which voltage is rectified by rectifier 6, so that a direct voltage is set up across resistance 1 and condenser 8. This direct voltage changes the bias of grid II, to thereby decrease the plate current of the tube and cause contact 2| to close circuit Hi.
When a signal frequency of more than 2,000 cycles per second is used, and when circuit, 5 is tuned to this frequency, there is little damping effect, and this circuit hasa sharp resonance curve with the result that the speech currents will not produce a suflicientvoltage drop across resistance 1 to cause contact 2| to close. 'This appears to be due to the much smaller amplitude and duration of the speech oscillations in comparison to these values for the speech current.
I prefer to use for impedance 20, a coil having an iron core (as shown) for the following reahigh and therefore the hysteresis and eddy-current losses and the damping will increase accordingly. Thus the circuit 5 will have a less sharp resonance curve for the signal currents.
' r 2,251,958 high amplitude, the magnetic induction will be The above is of course very, important because a i is makes it necessary to employ-special measures for maintaining either the natural frequency of circuit 5 or the signal frequency, constant, while,
at the same time insuring that relay 9 will be correctly actuated. Thus if the resonance curve were too broad, the relay 9 might respond to the speech currents.
- The apparatus shownjn Figure 2 is similar to that of Figure 1, and operates. in the same man'- ner. However, in Fig. 2 the oscillatory'circuit frequency, a rectifier, and a resistance.
51 which is tuned to the signal frequency is con nected in parallel with winding ll, softhat series resonance instead of parallel resonance is used.
For this purpose condenser I9 and impedance 2!] are connected in series across winding 14, and rectifier 6 is connected between a tap 22 on impedance 20, and a point 23 between windings l5 and resistance 1 and condenser 8;
While we have described our invention in connection with specific examples and applications, we do not wish to be limited thereto, but desire the appended claims to be construed as broadly as permissible in view of the prior art.
What we claim is:
1. A telephony receiving apparatus comprising a low frequency amplifier including a grid-controlled amplifier tube, said amplifier having a grid circuit to which are supplied the received speech frequency band and signal currents of a .2. A telephonyv receiving apparatus comprising a .-low-'frequency amplifier including a grid-controlled amplifier tube, said amplifier having a grid circuit tdwhich are supplied the received speech fr eque-ncy bands and signal currents of a 'frequency within the speech-frequency band and of amplitudes which are large relative to those of the speech currents, and an output circuit adapted to be connected to utilizationv means for the amplifiedspeecn current; controlling means in said output circuit tocontrol a signal circuit, said controlling means being controlled by the anode current of said tube, and means in said grid circuit and associated with the grid of said tube to change the grid voltage when signal currents are being supplied, said latter means comprising a rectifier, a resistance, and an oscillatory circuit 1 tuned to the signal frequency and includinga coil having an iron core.
THOMAS SAMUEL SKILLMAN. JAN WILLEM BAURDOUX. MATI-HAS VAN as BEEK.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE201132X | 1937-01-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
US2251958A true US2251958A (en) | 1941-08-12 |
Family
ID=5764685
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US184089A Expired - Lifetime US2251958A (en) | 1937-01-29 | 1938-01-08 | Telephony |
Country Status (4)
Country | Link |
---|---|
US (1) | US2251958A (en) |
CH (1) | CH201132A (en) |
FR (1) | FR832795A (en) |
GB (1) | GB487488A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2496784A (en) * | 1947-02-21 | 1950-02-07 | Hartford Nat Bank & Trust Co | Receiver circuit-arrangement for low-frequency or carrier wave telephony systems |
US20070272494A1 (en) * | 2006-05-24 | 2007-11-29 | Hans Kocher | Elevator with frictional drive |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1063220B (en) * | 1954-12-16 | 1959-08-13 | Sueddeutsche Telefon App Kabel | Tonrufempfaenger or converter for tone selection or tone control purposes for radio systems with selective call systems, in particular for radio networks with mobile radio systems |
-
1938
- 1938-01-08 US US184089A patent/US2251958A/en not_active Expired - Lifetime
- 1938-01-26 GB GB2508/38A patent/GB487488A/en not_active Expired
- 1938-01-27 CH CH201132D patent/CH201132A/en unknown
- 1938-01-29 FR FR832795D patent/FR832795A/en not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2496784A (en) * | 1947-02-21 | 1950-02-07 | Hartford Nat Bank & Trust Co | Receiver circuit-arrangement for low-frequency or carrier wave telephony systems |
US20070272494A1 (en) * | 2006-05-24 | 2007-11-29 | Hans Kocher | Elevator with frictional drive |
US8235178B2 (en) * | 2006-05-24 | 2012-08-07 | Inventio Ag | Elevator with frictional drive |
Also Published As
Publication number | Publication date |
---|---|
FR832795A (en) | 1938-10-03 |
CH201132A (en) | 1938-11-15 |
GB487488A (en) | 1938-06-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US2057613A (en) | Diversity factor receiving system | |
US2251958A (en) | Telephony | |
US2172453A (en) | Radio transmitter | |
US2100394A (en) | Reception of frequency modulated waves and circuits therefor | |
US2175990A (en) | Process and arrangement for increasing the maximum output of electron tubes | |
US2138613A (en) | Signaling system | |
US2182100A (en) | Automatic volume control device for wave transmission systems | |
US2210957A (en) | Signal receiver for carrier wave systems | |
US1776219A (en) | Signal-relay system | |
US2162268A (en) | Signaling system | |
US1872347A (en) | Amplifier tube control | |
US2141944A (en) | Automatic volume control for amplifiers | |
US2533803A (en) | Audio controlled limiter | |
US2093072A (en) | Amplifier gain control circuit | |
US2248857A (en) | Automatic bias corrector | |
US2282377A (en) | Control means for railway train communication apparatus | |
US1853678A (en) | Method of and means for separating desired from undesired electric currents | |
US1878046A (en) | Detector for modulated alternating currents | |
GB360891A (en) | Electrical frequency control systems | |
US2213034A (en) | Gain control circuits | |
US2085408A (en) | Diode rectifier circuit | |
US2138963A (en) | Level compensator for telegraph systems | |
US1567565A (en) | Receiving system | |
US1562500A (en) | Receiving circuits for low-frequency impulses | |
US2875413A (en) | Modulation system |