US2406803A - High-frequency electrical communication system - Google Patents
High-frequency electrical communication system Download PDFInfo
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- US2406803A US2406803A US468572A US46857242A US2406803A US 2406803 A US2406803 A US 2406803A US 468572 A US468572 A US 468572A US 46857242 A US46857242 A US 46857242A US 2406803 A US2406803 A US 2406803A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/04—Distributors combined with modulators or demodulators
- H04J3/042—Distributors with electron or gas discharge tubes
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K7/00—Modulating pulses with a continuously-variable modulating signal
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B14/00—Transmission systems not characterised by the medium used for transmission
- H04B14/02—Transmission systems not characterised by the medium used for transmission characterised by the use of pulse modulation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/02—Details
- H04J3/12—Arrangements providing for calling or supervisory signals
Definitions
- a constant carrier or radio frequency generator which'. is set into oscillation b'y one ⁇ edge of a sharpsh'ort pulse (say the loading edge).
- This oscillation buildsrup to a steady value in ati-ineI depending onthe sharp'- ticular usefulness lies -inf the dissemination of politicians, stoppage of unwanted transmissiom or transmission ofintelli'gfence over a large band of frequencies.
- one sig-nal can transmit intelligence within' i6 dbs: level ⁇ over a band Width of 300 kc./s., the signals being received at frequency intervals throughout this band and' the intervals being. solely governed by the frequency of repetition of theV pulses.
- the present invention has for its object to provide another .rr'iethodI of and other arrangements for achieving similar results.
- Another .objectof ⁇ ⁇ the invention is to render frequency modulation intelligible in an amplitudeV modulation receiver.
- An electrical signal transmission system according t'o the invention is characterised in that-once a pulse train-has been initiatedi. e. a pulse duration of a certain repetitionfreq'ue'ncy has been rdecidedV upon,v the frequency or phase of the carrier alone is varied either directly or indirectly according to the instantaneous amplitude of ⁇ the intelligence Wave. ⁇
- the trains ofr oscillations have initial amplitudeswhich are characteristic ofthe modulating intelligence Wave.
- the transmission assumes the charactersticsl of anumber of satellite side bandtransmissions; y
- its phase be advanced and retarded sinusoidally (say) between -I-oi and p2 with respect to the unmodulated state (e020).
- the Y vector remaining constant during the operation. This results in a peak-to-peak modulation (p14-qm) but it is important to note that only at the extreme excursion positions is the frequency of the rwave identical to the unmodulated state, the frequency having alternately increased and decreased With frequency maxima and minima occurring at P, the unmodulated state. In other words, the instants of maximum phase.
- phase modulation is assumed to be a certain function if, the frequency modulation is inherently the rate of change of phase, i. e., the frequency modulation is a function, ⁇ I' where ⁇ lf is the first differential Vwith respect to time of In
- ⁇ I' where ⁇ lf is the first differential Vwith respect to time of
- the applied oscillation amplitude results. This is shown in chain-line in Fig. 3. This would also be the case if three or other odd number of half-cycles of the applied oscillation occurred during the pulse duration. It will be observed that the amplitude of the damped trains set up in the circuit is dependent upon the frequency of the applied oscillations, providing the applied oscillations are interrupted contemporaneously with the trailing edge of the pulse, and that the applied oscillation Vswings through Zero during the leading edge of the pulse. There thus occurs the interaction of the Adamped waves due to the continued damped oscillation of the circuit on account of the applied oscillation (now terfminated) and the damped oscillation set up by thechange of voltage due to the trailing edge of the pulse. The result is a damped train of waves whose frequency is that of the applied oscillations and whose amplitude depends upon the Yrelation between the pulse duration and the periodic time of the applied oscillations.
- the amplitude of the 4 damped waves generated could be amplified and 'In one way of carrying out the invention constant duration pulses are used, since the deviation of the carrier frequency is made characteristic of the intelligence. This is achieved by frequencymodulating a carrier wave in a certain predetermined manner, and then modulating by a train4 of pulses of constant duration.
- phasemodulation to provide a similar result will be apparent to those skilled in the art from the description hereinbefore given on ⁇ the similarity between phase and frequency modulation.
- the term angular modulation is used herein to denote both frequency and phase modulation.
- a pulse which is applied to a resonant circuit is shown as of such duration that one cycle of a carrier wave applied to the same circuit is allowed to occur.
- the pulse is shown as occurring as the oscillation swings in the positive direction and the forced oscillation set up by the trailing edge of the pulse is in opposition t0 the applied oscillation.
- the resultant amplitude of the circuit oscillation is zero, so that if the applied oscillations are interrupted at the'moment of the trailing edge of the pulse, the circuit ceases to oscillate.
- the voltage induced by the trailing edge 2 will be in phase with the applied oscillation, and a voltage of twice passed through a limiting device, hence eliminating the amplitude modulation.
- the amplitude modulation is used, forced reception in receivers for amplitude modulated waves is obtained over a wide range of carrier frequencies and these carrier frequencies are determined by the pulse repetition frequency of the constant duration pulses applied to the circuit which produces the damped trains.
- Fig. 4 shows in block diagram an arrangement for carrying out the invention.
- 3 represents a pulse generator, the output of which causes os cillator l!A to start and stop as described,
- the frequency at which this oscillator oscillates at any time is characteristic of the signal (i. e. the output of the modulation amplifier 5), thig frequency Y being generated by any known method,
- Fig. 5 The details 'of one circuit arrangement embodying the invention is shown in Fig. 5.
- the carrier is provided by an oscillator cut in and out of use under the control of ⁇ that a positive pulse is applied to the grid thereof from a valve i which is the output valve of a pulse generator.
- the frequency at which valve 6 oscillates is governed, not only by C, but by the input capacitance of valve 9 which is in parallel with the tuned circuit l.
- the input capacitance of valve 9 can be'made to vary by varying its bias voltage, which can be made to represent a given modulationA signal,V obtained from valve if! and its associated circuit.
- the valve il! may, for instance be an amplifier for the intelligence wave to be transmitted, and whose output is passed Vassiduo?,
- Y throughV a bias resistance in the grid-cathode circuit of the valve 9,.
- a capacity Il is connected between the grid of 9 and the tuned circuit LC of valve 6.
- the resulting varying dampedl train formed in circuit 'I may be obtained by any known method of coupling shown in the drawing as' being inductively coupled to L, .and should .preferably be transferred directto a transmitting aerial indicated at A.
- An electrical wave signal transmission system comprising means for generating short trains of damped carrier waves, an intelligence wave source, means for subjecting the carrier waves comprising said wave trains to angular modulation in accordance with the instantaneous amplitude of the intelligence Wave, and means for impressing the resultant modulated wave trains upon a transmission medium.
- An electrical Wave signal transmission system comprising an oscillator for generating carrier waves, a source of constantly repetitive electrical pulses, an intelligence wave source, means for applying said pulses to said oscillator to cause it to generate short trains of carrier waves, the duration of a train after the end of the initiating pulse depending on the duration of said pulse, means for angularly modulating the carrier waves comprising said Ywave trains in accordance with the instantaneous amplitude of the intelligence wave, and means for impressing the resultant modulated wave trains upon a transmission medium.
- An electrical wave signal transmission system comprising an oscillator including an electron tube having a cathode, an anode, a control grid, and regeneratively coupled anode and grid circuits, means for negatively biasing said grid .
- a source of positive electrical pulses means for applying said pulses to said grid so as to cause said oscillator to generate shorttrains of carrier waves, means to cause the time duration of said pulses to determine the time duration of said trains in excess of said pulses, an intelligence wave source, means for angularly modulating said trains of carrier waves in accordance with the instantaneous amplitude of the intelligence wave, and means for impressing the resultant modulated wave trains upon a transmission medium.
- An electrical wave signal transmission system comprising means for generating short trains of carrier waves, a source of constantly repetitive electrical pulses of constant time duration, an intelligence wave source, means kfor angularly modulating said carrier waves comprising the respective trains in accordance with the instantaneous amplitude of said intelligence wave, a resonant circuit, means for applying said carrier waves to said resonant circuit, means for applying said pulses to said resonant circuit in such time relation with respect to said carrier waves that each pulse is applied substantially at the instant when the carrier amplitude is passing through zero amplitude in the same direction as the pulse, and means for coupling said resonant circuit with a transmission medium.
- the method of electrical carrier wave signal transmission which comprises generating short damped trains of carrier waves, angularly modulating the carrier waves comprising the respective trains in accordance with the rinstantaneous amplitude of an intelligence wave to be transmitted, and amplitude modulating the initial amplitude ,of .the respective trains also in accordance with the instantaneous amplitude of 4-saidintelligence Wave.
- vto set said'oscillator into oscillation and are applied also to the said resonant circuit whilst the intelligence wave to be transmitted as the angular modulation of said trains of waves is applied to control the frequency of said resonant circuit.
- said resonant circuit includes a capacity comprising the grid-cathode capacity of a thermionic tube and means is provided to apply said intelligence wave to Vary the grid bias of said last-mentioned tube in accordance with the amplitude of said intelligence wave.
- said resonant circuit is coupled to a radiant acting antenna.
- the method of electrical carrier wave signal transmission which comprises generating a first series of vshort trains of damped carrier waves, superposing a second series of short trains of damped carrier waves on said first series, displaced a predetermined constant time with respect to said first series, and varying the frequency of said carrier Waves of both said series in accordance with the instantaneous value of an intelligence wave to be transmitted.
- An electrical wave signal transmission system comprising a resonant circuit, means to vary the resonance of said circuit in accordance with the instantaneous Values of an intelligence wave to be transmitted, means t0 apply an oscillation at the frequency of said resonant circuit to said circuit for repeated short periods of time, Whereby trains of damped oscillations are set up in said resonant circuit, means for repeatedly shocking said resonant circuit at a constant time after the setting up of said trains of oscillations, whereby additional trains of oscillations of the same frequency are set up in said circ-uit having a phase relation to the oscillations of said first trains which is dependent on said constant time, a transmission medium, and means for impressing the resultant modulated oscillation trains in said resonant circuit upon said transmission medium.
- An' electrical wave signal transmission system comprising a resonant circuit, means to vary they resonance of said circuit in accordance with an intelligence wave to be transmitted, means to generate short trains of damped. carrier waves in said resonant circuit at the frequency of said circuit, means to generate additional trains of carrier waves in said circuit at a constant period of time after the initiation of said rst wave trains, said period of time being such as to give a maximum output of said resonant circuit as a resultant of both said trains of carrier Waves for one extreme frequency adjustment of said resonant circuit, whereby the resultant of said two trains of carrier waves Will depend for its amplitude on said period of time, a transmitting medium, and
- a resonant circuit means to initiate in said resonant circuit trains of oscillations atthe irequency of said circuit, said means being operative for the time duration of said pulses, whereby'the trains of carrier waves continue as damped oscillations after the cessation of said initiating means, means to apply said pulses to said resonant circuit so as to create additional trains of
Description
Sept. 3; 1946. P. K; CHATTERJEA ET A1. 2.4065803 HIGH FREQUENCY ELECTRICAL COMMUNICATION SYSTEM Filed nec. 1o. 1942 AAAA . Attorney Patented Sept. 3, 1946 HIGH-FREQUENCY ELECTRICAL COMMUNICATION. SYSTEM' Prafulla- Kumar Chatterjea and Leslie Wilfred Houghton', London W. C. 2, England, assignors to Standard Telephones and Cables Limited,
London, England, a. British company v Y Appiication December 10, 1era seriali No.r4ss,572
- In Great` Britain December 16, 1941 .1 g In nearly all time modulated pulse systems used for transmitting intelligence of any kind, the' amplitude of the*A signal` obtained at the receiver is some-.function of the total time occurring between the lead-ing and trailing edges of av pulse in a trai-n of time Vmodulated pulses and it`V is necessary to determine in general the duration of each individual pulse to reconstructY the intelligence..` A method of and arrangements for utilising pulseswhich are time modulated as a function of the amplitude of a sound or like Wave have been proposed in which the desired intelligence can be obtained from` one edge only of the sai time modulated pulse'.` K l g The operation of this latter systemv is dependent upon transmitting atrai-nof pulses so time` modulated that said pulses-have a function characteristic of the Aanfipl-itude of asound: or like Wave (hereinafter also called intelligence Wave), said time modulation7 bei-ng characterise'd in that the ,time interval between the limitsof modulation is equal to the time taken for a fraction (preferably less than lyg) of a Wavelength period of a radio frequency (this frequency itself islarge compared with the pulse repetition frequency). At areceiver said pulses .are used 13 claims. (Cl. 25o-'17) by modifying the slope of one of tlie edges ofthe pulses-Lpreferably the edge which normally oc-v curs at equal intervals of time, and preferably the A.trailing edge.- Here thenV the' slopesf of the trailing edge are characteristic of' the' amplitudes' of a sound or like vvave.- Inpractice, itis foundY that actually both edges are' modified.
The special advantages obtained from' these method-sy and-arrangementsare various, andpar-j tointerrupt a train' o'f oscillations (thesefbeing v at the carrier, i. e. at the said radio frequency) and thel amplitude ci" the intelligence vwave r'eceived is a function of the amplitude ofv the damped oscillations at the interruptions' of the pulse' train, which in turn is dependent at any' y m'oment on tlie time duration of the pulses-tinsV duration being modulated byY the intelligence Waveiny the manner described hereinbefore'.
The main requirement of such a system is1 to have at the transmitter a constant carrier (or radio frequency generator which'. is set into oscillation b'y one` edge of a sharpsh'ort pulse (say the loading edge). This oscillation buildsrup to a steady value in ati-ineI depending onthe sharp'- ticular usefulness lies -inf the dissemination of propaganda, stoppage of unwanted transmissiom or transmission ofintelli'gfence over a large band of frequencies. For example', one sig-nal can transmit intelligence within' i6 dbs: level` over a band Width of 300 kc./s., the signals being received at frequency intervals throughout this band and' the intervals being. solely governed by the frequency of repetition of theV pulses. r-
The present invention has for its object to provide another .rr'iethodI of and other arrangements for achieving similar results. v Another .objectof` `the invention is to render frequency modulation intelligible in an amplitudeV modulation receiver. An electrical signal transmission system according t'o the invention is characterised in that-once a pulse train-has been initiatedi. e. a pulse duration of a certain repetitionfreq'ue'ncy has been rdecidedV upon,v the frequency or phase of the carrier alone is varied either directly or indirectly according to the instantaneous amplitude of` the intelligence Wave.`
nessv of the initial rise' of the' pulse, among other factors, and the duration of the pulse. The'trailing edge of the same pulse in Ythis case initiates another forced oscillation intol the circuit', the^v initial amplituilel of this' second sety of oscillations being determi-ned mainly by the'v duration of the pulse, other factors being' constant.
Id'eallyfo'f courseY the edges oi the pulse have to' be absolutely straight tomake possible the proper control of the initial' stage" of the" damped' oscillation, this is inv generall rather di-iicult1 t0 achieve without extra precautionin thev circuit design.
If fc be the carrier frequency at which the transmitter output is tuned, a change ofv this j@ equal to l -Afc is-made characteristic of the amplitude ofthe intelligence Wave,` whilst the pulse duration, the pulse repetition frequency, and the pulse slope arel maintained constant. v
According to a feature of the invention the trains ofr oscillations have initial amplitudeswhich are characteristic ofthe modulating intelligence Wave. As in all pulse transmission systems the transmission assumes the charactersticsl of anumber of satellite side bandtransmissions; y
, Using only the1 frequency modulation system faccording'to the" present invention, intelligible rece'ption` cannot-nodi be obtained in' receivers de'- signe'df only" for4 amplitude modulated' Waves'v be= cause a detectcr'for' amplitude modulated Waves by itself is immune to Variations of frequency of in its simplest form can be shown to result in frequency modulation.
In Fig. 1 of the accompanying drawing is shown a vector OP representing an unmodulated carrier frequency w/21r where w=21rf, f being the frequency. Let its phase be advanced and retarded sinusoidally (say) between -I-oi and p2 with respect to the unmodulated state (e020). the Y vector remaining constant during the operation. This results in a peak-to-peak modulation (p14-qm) but it is important to note that only at the extreme excursion positions is the frequency of the rwave identical to the unmodulated state, the frequency having alternately increased and decreased With frequency maxima and minima occurring at P, the unmodulated state. In other words, the instants of maximum phase. displacement and maximum frequency change are displaced from each other by 90 at the modulating frequency. Thus if phase modulation is assumed to be a certain function if, the frequency modulation is inherently the rate of change of phase, i. e., the frequency modulation is a function, \I' where \lf is the first differential Vwith respect to time of In A very simple case is shown here to express the similarity Ybetween frequency modulation and phase modulation. It is known that constant phase modulation at all modulating frequencies results actually in more frequency modulation when higher modulation frequencies are used than for lower modulating frequencies.
the applied oscillation amplitude results. This is shown in chain-line in Fig. 3. This would also be the case if three or other odd number of half-cycles of the applied oscillation occurred during the pulse duration. It will be observed that the amplitude of the damped trains set up in the circuit is dependent upon the frequency of the applied oscillations, providing the applied oscillations are interrupted contemporaneously with the trailing edge of the pulse, and that the applied oscillation Vswings through Zero during the leading edge of the pulse. There thus occurs the interaction of the Adamped waves due to the continued damped oscillation of the circuit on account of the applied oscillation (now terfminated) and the damped oscillation set up by thechange of voltage due to the trailing edge of the pulse. The result is a damped train of waves whose frequency is that of the applied oscillations and whose amplitude depends upon the Yrelation between the pulse duration and the periodic time of the applied oscillations.
Thus if the frequency of the applied oscillations is made to depend upon the instantaneous amplitude of an intelligence or other wave, both the frequency of the damped waves and the amplitude Vthereof carry the intelligence and the amplitude modulation can be received by receivers designed for amplitude modulated waves, whilst frequency modulation can only be received by receivers designed for reception of frequency modulated waves. It will be understood by those versed in the art that the amplitude of the 4 damped waves generated could be amplified and 'In one way of carrying out the invention constant duration pulses are used, since the deviation of the carrier frequency is made characteristic of the intelligence. This is achieved by frequencymodulating a carrier wave in a certain predetermined manner, and then modulating by a train4 of pulses of constant duration. The application of phasemodulation to provide a similar result will be apparent to those skilled in the art from the description hereinbefore given on `the similarity between phase and frequency modulation. The term angular modulation is used herein to denote both frequency and phase modulation.
The invention will be further elucidated in the following description. Referring to Fig. 2 of the accompanyingdrawing, a pulse which is applied to a resonant circuit is shown as of such duration that one cycle of a carrier wave applied to the same circuit is allowed to occur. The pulse is shown as occurring as the oscillation swings in the positive direction and the forced oscillation set up by the trailing edge of the pulse is in opposition t0 the applied oscillation. Assuming that the amplitude of the forced oscillation is equal to the amplitude of the applied oscillation, the resultant amplitude of the circuit oscillation is zero, so that if the applied oscillations are interrupted at the'moment of the trailing edge of the pulse, the circuit ceases to oscillate. If the oscila lation frequency is as shown in Fig. 3, the voltage induced by the trailing edge 2 will be in phase with the applied oscillation, and a voltage of twice passed through a limiting device, hence eliminating the amplitude modulation. When the amplitude modulation is used, forced reception in receivers for amplitude modulated waves is obtained over a wide range of carrier frequencies and these carrier frequencies are determined by the pulse repetition frequency of the constant duration pulses applied to the circuit which produces the damped trains.
Fig. 4 shows in block diagram an arrangement for carrying out the invention. Here 3 represents a pulse generator, the output of which causes os cillator l!A to start and stop as described, The frequency at which this oscillator oscillates at any time is characteristic of the signal (i. e. the output of the modulation amplifier 5), thig frequency Y being generated by any known method,
The details 'of one circuit arrangement embodying the invention is shown in Fig. 5. InV this arrangement the carrier is provided by an oscillator cut in and out of use under the control of `that a positive pulse is applied to the grid thereof from a valve i which is the output valve of a pulse generator. The frequency at which valve 6 oscillates is governed, not only by C, but by the input capacitance of valve 9 which is in parallel with the tuned circuit l. By means of the circuit associated with valve 9 the input capacitance of valve 9 can be'made to vary by varying its bias voltage, which can be made to represent a given modulationA signal,V obtained from valve if! and its associated circuit. rThe valve il! may, for instance be an amplifier for the intelligence wave to be transmitted, and whose output is passed Vassiduo?,
Y throughV a bias resistance in the grid-cathode circuit of the valve 9,. A capacity Il is connected between the grid of 9 and the tuned circuit LC of valve 6.
The resulting varying dampedl train formed in circuit 'I may be obtained by any known method of coupling shown in the drawing as' being inductively coupled to L, .and should .preferably be transferred directto a transmitting aerial indicated at A.
What is claimed is:
1. An electrical wave signal transmission system comprising means for generating short trains of damped carrier waves, an intelligence wave source, means for subjecting the carrier waves comprising said wave trains to angular modulation in accordance with the instantaneous amplitude of the intelligence Wave, and means for impressing the resultant modulated wave trains upon a transmission medium.
2. An electrical Wave signal transmission system comprising an oscillator for generating carrier waves, a source of constantly repetitive electrical pulses, an intelligence wave source, means for applying said pulses to said oscillator to cause it to generate short trains of carrier waves, the duration of a train after the end of the initiating pulse depending on the duration of said pulse, means for angularly modulating the carrier waves comprising said Ywave trains in accordance with the instantaneous amplitude of the intelligence wave, and means for impressing the resultant modulated wave trains upon a transmission medium.
3. An electrical wave signal transmission system comprising an oscillator including an electron tube having a cathode, an anode, a control grid, and regeneratively coupled anode and grid circuits, means for negatively biasing said grid .to
inhibit oscillation, a source of positive electrical pulses, means for applying said pulses to said grid so as to cause said oscillator to generate shorttrains of carrier waves, means to cause the time duration of said pulses to determine the time duration of said trains in excess of said pulses, an intelligence wave source, means for angularly modulating said trains of carrier waves in accordance with the instantaneous amplitude of the intelligence wave, and means for impressing the resultant modulated wave trains upon a transmission medium.
4. An electrical wave signal transmission system comprising means for generating short trains of carrier waves, a source of constantly repetitive electrical pulses of constant time duration, an intelligence wave source, means kfor angularly modulating said carrier waves comprising the respective trains in accordance with the instantaneous amplitude of said intelligence wave, a resonant circuit, means for applying said carrier waves to said resonant circuit, means for applying said pulses to said resonant circuit in such time relation with respect to said carrier waves that each pulse is applied substantially at the instant when the carrier amplitude is passing through zero amplitude in the same direction as the pulse, and means for coupling said resonant circuit with a transmission medium.
5. The method of electrical carrier wave signal transmission which comprises generating short damped trains of carrier waves, angularly modulating the carrier waves comprising the respective trains in accordance with the rinstantaneous amplitude of an intelligence wave to be transmitted, and amplitude modulating the initial amplitude ,of .the respective trains also in accordance with the instantaneous amplitude of 4-saidintelligence Wave.
vto set said'oscillator into oscillation and are applied also to the said resonant circuit whilst the intelligence wave to be transmitted as the angular modulation of said trains of waves is applied to control the frequency of said resonant circuit.
7. An electrical signal transmission system as claimed in claim 4 wherein the said intelligence wave is applied to control a capacity in said resonant circ-uit.
8. An electrical signal transmission system as claimed in claim 4 wherein said resonant circuit includes a capacity comprising the grid-cathode capacity of a thermionic tube and means is provided to apply said intelligence wave to Vary the grid bias of said last-mentioned tube in accordance with the amplitude of said intelligence wave.
9. An electrical signal transmission system as.
claimed in claim 4 wherein said resonant circuit is coupled to a radiant acting antenna.
10. The method of electrical carrier wave signal transmission which comprises generating a first series of vshort trains of damped carrier waves, superposing a second series of short trains of damped carrier waves on said first series, displaced a predetermined constant time with respect to said first series, and varying the frequency of said carrier Waves of both said series in accordance with the instantaneous value of an intelligence wave to be transmitted. l
11. An electrical wave signal transmission system comprising a resonant circuit, means to vary the resonance of said circuit in accordance with the instantaneous Values of an intelligence wave to be transmitted, means t0 apply an oscillation at the frequency of said resonant circuit to said circuit for repeated short periods of time, Whereby trains of damped oscillations are set up in said resonant circuit, means for repeatedly shocking said resonant circuit at a constant time after the setting up of said trains of oscillations, whereby additional trains of oscillations of the same frequency are set up in said circ-uit having a phase relation to the oscillations of said first trains which is dependent on said constant time, a transmission medium, and means for impressing the resultant modulated oscillation trains in said resonant circuit upon said transmission medium.
12. An' electrical wave signal transmission system, comprising a resonant circuit, means to vary they resonance of said circuit in accordance with an intelligence wave to be transmitted, means to generate short trains of damped. carrier waves in said resonant circuit at the frequency of said circuit, means to generate additional trains of carrier waves in said circuit at a constant period of time after the initiation of said rst wave trains, said period of time being such as to give a maximum output of said resonant circuit as a resultant of both said trains of carrier Waves for one extreme frequency adjustment of said resonant circuit, whereby the resultant of said two trains of carrier waves Will depend for its amplitude on said period of time, a transmitting medium, and
- means for impressing said resultant modulated repetitive electrical pulses of constant time duration, a resonant circuit, means to initiate in said resonant circuit trains of oscillations atthe irequency of said circuit, said means being operative for the time duration of said pulses, whereby'the trains of carrier waves continue as damped oscillations after the cessation of said initiating means, means to apply said pulses to said resonant circuit so as to create additional trains of
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB2406803X | 1941-12-16 | ||
| GB1198745A GB596676A (en) | 1945-05-12 | Improvements in or relating to electric pulse signalling systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2406803A true US2406803A (en) | 1946-09-03 |
Family
ID=32178902
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US468572A Expired - Lifetime US2406803A (en) | 1941-12-16 | 1942-12-10 | High-frequency electrical communication system |
| US679999A Expired - Lifetime US2546974A (en) | 1941-12-16 | 1946-06-28 | Pulse multiplex signaling system |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US679999A Expired - Lifetime US2546974A (en) | 1941-12-16 | 1946-06-28 | Pulse multiplex signaling system |
Country Status (5)
| Country | Link |
|---|---|
| US (2) | US2406803A (en) |
| BE (1) | BE472518A (en) |
| CH (1) | CH267010A (en) |
| FR (2) | FR939269A (en) |
| NL (1) | NL77429C (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2584739A (en) * | 1948-07-24 | 1952-02-05 | Gen Railway Signal Co | Centralized traffic controlling system |
| US3067391A (en) * | 1959-02-25 | 1962-12-04 | Floyd J Keirnan | Variable spectrum pulse generator |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2832832A (en) * | 1952-12-17 | 1958-04-29 | Gen Dynamics Corp | Telephone system |
| US2945094A (en) * | 1954-09-07 | 1960-07-12 | Itt | Pulse signalling system |
| US3023372A (en) * | 1958-01-13 | 1962-02-27 | Thompson Ramo Wooldridge Inc | Precision variable frequency generator |
| US3158691A (en) * | 1961-06-07 | 1964-11-24 | Gen Dynamics Corp | Ramp pulse position multiplex system |
| US3146314A (en) * | 1961-09-25 | 1964-08-25 | Gen Dynamics Corp | Means for generating warbling tone ringing signals in a time division multiplex communication system |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2007809A (en) * | 1930-10-04 | 1935-07-09 | Communications Patents Inc | Thermionic switching system |
| GB523575A (en) * | 1939-01-06 | 1940-07-17 | Kolster Brandes Ltd | Improvements in or relating to methods of generating pulses characteristic of sound and like waves |
| US2263369A (en) * | 1939-02-03 | 1941-11-18 | Hartford Nat Bank & Trust Co | Multiplex telephony system |
| FR959084A (en) * | 1942-12-04 | 1950-03-23 | ||
| BE462299A (en) * | 1943-10-19 | |||
| US2429613A (en) * | 1943-10-19 | 1947-10-28 | Standard Telephones Cables Ltd | Pulse multiplex communication system |
| US2418116A (en) * | 1943-12-20 | 1947-04-01 | Standard Telephones Cables Ltd | Multiplex synchronizing system |
| US2408077A (en) * | 1944-08-25 | 1946-09-24 | Standard Telephones Cables Ltd | Multichannel system |
-
1942
- 1942-12-10 US US468572A patent/US2406803A/en not_active Expired - Lifetime
-
1946
- 1946-06-28 US US679999A patent/US2546974A/en not_active Expired - Lifetime
- 1946-08-28 FR FR939269D patent/FR939269A/en not_active Expired
-
1947
- 1947-04-14 BE BE472518D patent/BE472518A/xx unknown
- 1947-10-08 CH CH267010D patent/CH267010A/en unknown
- 1947-11-14 NL NL136036A patent/NL77429C/xx active
- 1947-12-23 FR FR58158D patent/FR58158E/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2584739A (en) * | 1948-07-24 | 1952-02-05 | Gen Railway Signal Co | Centralized traffic controlling system |
| US3067391A (en) * | 1959-02-25 | 1962-12-04 | Floyd J Keirnan | Variable spectrum pulse generator |
Also Published As
| Publication number | Publication date |
|---|---|
| CH267010A (en) | 1950-02-28 |
| US2546974A (en) | 1951-04-03 |
| FR939269A (en) | 1948-11-09 |
| NL77429C (en) | 1955-03-15 |
| FR58158E (en) | 1953-09-29 |
| BE472518A (en) | 1947-10-14 |
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