US2403210A - Multiplex pulse modulation system - Google Patents

Multiplex pulse modulation system Download PDF

Info

Publication number
US2403210A
US2403210A US522350A US52235044A US2403210A US 2403210 A US2403210 A US 2403210A US 522350 A US522350 A US 522350A US 52235044 A US52235044 A US 52235044A US 2403210 A US2403210 A US 2403210A
Authority
US
United States
Prior art keywords
pulses
valve
pulse
channel
grid
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
Application number
US522350A
Other languages
English (en)
Inventor
Butement William Alan Stewart
Oxford Alan John Henry
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Application granted granted Critical
Publication of US2403210A publication Critical patent/US2403210A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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

Definitions

  • the present invention relates to electrical signalling systems of the type in which the signals, for example speech signals, are transmitted as fixed-amplitude pulses of radio frequency occurring at a fixed repetition frequency higher than the highest signal frequency it is desired to transmit and having a duration which varies in accordance with the instantaneous amplitude of the signals.
  • Such pulses will be hereinafter referred to as variable-width pulses.
  • a further object of the invention is to provide a multi-channel system in which the equipment necessary is lighter and smaller and is simpler and cheaper to construct than that of multichannel systems hitherto proposed, and in which the power available per channel is greater and the eifect of noise or-fading less than in previouslyproposed systems.
  • an electrical signalling system of the type described wherein signals from a number of channels are transmitted in the form of a train of variable-width pulses for each channel over a single link to a receiving point together with a train of marker" pulses of a fixed width ap- 9 Claims. (01.
  • v tial to the control and suppressor grids of a pen; tode valve the interlaced trains of positive pulses being applied to one of these grids, the other grid preciably greater than the maximum width of the signal pulses, the pulses in each train having the same repetition frequency but being displaced in time relative to one another so that they can be interlaced for transmission over the single link, and wherein (at the receiving point) the marker pulses are separated from the signal pulses and are utilized to generate for each channel a train of "stroboscope pulses of fixed width and of the same repetition frequency and timing as the signal pulses of that channel, the stroboscope" pulses being utilized to effect the separation of the trains of signal pulses from one another.
  • trains of pulses displaced in time relative to one another are generated by applying a saw-toothed wave of the desired repetition frequency to the control grids of a number of valves having an initial grid potential which is negative with respect to the cathode potential, the sudden drop in the anode voltage of each valve which occurs each time the rising grid potential approximately equals the cathode potential being utilized to develop a pulse, whereby each valve is used in developing a separate train of pulses, the relative timing of any two trains being determined by the relative values of the initial potential difference between the cathode and control corresponding valves.
  • a particular train of variable width pulses is selected from a number of interlaced trains of variable width pulses by applying a negative potenhaving applied thereto a train of positive strobo-- scope pulses of the same frequency and timing,-v as the train'to be selected, and of a fixed-width equal to the maximum width of the pulses to be selected, whereby the valve conducts only during the periods when a stroboscope pulse and a pulse of the train to be selected are simultaneously present,
  • FIG. 1 is an explanatory diagram showing the interlacing of the pulses
  • Fig. 21 s a simple form oftransmitter
  • Fig. 3 is a series of curves showing the ,voltages at the electrodes of the valves of Fig. 2":
  • Fig. 4 is a schematic diagram of simple form of receiver
  • Fig. 5 shows the transmitted wave form of the preferred system
  • Fig. 6 is a circuit diagram of a preferred form of pulse generating system
  • Fig. 7 is a series of curves illustrating the generation of the marker pulses.
  • Fig. 8 is a circuit diagram of the preferred receiving. circuit.
  • the pulse train for each speech channel comprises pulses recurring at a fixed repetition frequency of approximately 9100 per second, the width of the pulses varying in accordance with the speech modulation in such a way that at a maximum depth of modulation they have a duration of 8 microseconds and at a minimum depth they have a duration of 2 microseconds.
  • the pulse train for the marker" channel by means of which the fixed repetition frequency at which all the channels operate is congrid of the two I veyed to the receiver and there used to sort out the various spefiih channels. comprises pulses ot fixed width rec ring at the 9100 cycle repetition frequency the duration of each pulse being 14 microseconds; *The manner in which the nine l trains of pulses'are interlaced is shown in Fig. 1.
  • the pulse varying, in accordance with the speech modulation. This is followed by a second gap of 3% microseconds, and a-second period of 8 microdare not essential to should be appreciably longer than the maximum Vi duration of thespeech pulses in order that it can be satisfactorily separated from them at the receiver. Itis also essential that the maximum 1 duration ofthe speech pulses should be limited to allow an adequate gap between consecutive pulses or maximum width and that the minimum dura- I tion otthe speechjpulses and of this gap should.
  • the transmitter compriseseightseries of valves for generating thespeech channel pulses (one series being provided for each channel) and a ninth series for generating the marker pulses.
  • the ninth series is indicated by the references VIA and V2A, whilst the first two only of the speech channel pulsegenerators are shown (-VlB--V3B and VIC-V30).
  • a common output 'valve V4 is provided for allthe nine series.
  • the cathode of each of the first valves is connected to a different tapping on a potentiometer l, the cathode for the first generator VlB being the least and that for the eighth, the most positive.
  • the pulses for the first speech channel are generated as follows:
  • the first valve is connected through a condenser-resistance network 5, 6 to the control grid of a second valve V213, this grid being'normally held slightly positive.
  • the anode potential of this second valve is normally at a low potential except during this negative pulse on the grid, so that a condenser I connected between the anode and earth begins to charge at the beginning of the grid pulse and is suddenly discharged at the end of it.
  • Negative pulses, 0r pulses of reduced anode voltage, lasting from t 0 to lasting from 2-8 microseconds. pulses of anode current vary in width from cycle to "cycle 'sinusoidally in accordance with the No. 1 are applied.
  • the anode of-the modulator valve is held positive except during this period when the grid is driven positive, on which occasion it is driven negative due to the surge of anode current
  • the pulses for the second channel are generated in exactly the same way (curve F,.H. J, L
  • the pulses for the remaining channels are successively delayed by equal amounts by appropriate choice of the cathode potentials for the first valve in each case.
  • the anode circuits of all the eight modulator valves are connected to the control grid of the common output valve, so that the negative pulses generated by eachot these valves are applied to the grid one after the other (curve 0, Fig. 3).
  • the output of this valve is used to modulate an ultra-short wave radio sender 9.
  • the transmitted signal is received on a normal receiver l0. (Fig. 4) of the supersonic heterodyne type having 'a pass-band wide enough to handle the narrowest pulses which may occur.
  • the output of the second detector of the receiver will consist of the series of interlaced pulses already described.
  • the first step is to reproduce at the receiving point the repetition frequency at which all the channels operate. This is done by applying a portion of the output: of the second detector to the arid of a valve ll, whose function is to convert the positive pulses occurring, in this output into negative pulses. It the output already consists of negative pulses this valve is not required.
  • the negative pulses are applied to the of Fig. 3.
  • the required pulses appear in'the' anode circuit of the second valve.
  • the other portion of the output from the-second detector of the receiver is fed to the control grids of eight pentode valves Pl-P8 connected in parallel.
  • the valve passes current only during the periods when the stroboscopepulses andthe speech pulses Of channel I are simultaneously present and consequently there will app ar in the output circuit only the pulses of the first speech channel.
  • the second train oi stroboscope pulse irom-G2 are applied to the suppressor grid of the second pentode valve P2, sothat there will appear in the output circuit of this valve only the pulses of.” the second speech channel, and so on.
  • pulses of the eight speech channels have been sorted out from one another.
  • the eight pentode valves are connected to output circuits: ol-oaj control grid of a valve l2, the cathode of which is held slightly negative, so that the valve passes anode current of saturation value except during the persistence oi! the pulses.
  • a condenser ll connected between the node of this valve and earth will thus charge during the persistence of each pulse and will discharge suddenly at the end or the pulse: the voltage to which the condenser is. charged willdepend upon the length of the pulse.
  • the condenser voltage will reach a greater positive value at the end or the period or application 01' a marker pulse to the grid of the valve than at the end of the period of application of any speech pulse.
  • Thevoltages developed across the condenser are applied to the control grid of a second valve ll, the cathode potential of which is held at such a positive value that only the voltages produced by the marker pulses can cause any pamage oi anode current.
  • the condenser voltages produced by the speech pulses are insuillcient to swing the grid positive. Consequently, pulses corresponding to the marker pulses only appear in the anode. circuit of the second valve;
  • Irequencyand are used to lock an oscillator i6 generating a saw-toothed wave substantially identical with that employed at the transmitter.
  • oscillator i6 By means of a. slightly modified version of the process already wave is utilized .to generate eight trains of positive pulses, which may be termed stroboscope" pulses. Thme are unmodulated, having a fixed duration 018 microseconds, and the pulses in grammatically at GI-GB in Fig. 4.
  • Each comprises a pair of valves connected i the same way as the first two valves o!
  • each speech channel pulse generator and operating in the manner already described and illustrated in curves E-H described, for the transmitter, this saw-toothed each train are in step with thosein the correwhich contai any known or suitable. arrangemitt" for integrating the variable width pulses andthus converting them into oscillations of speech frequency, andalso suitable terminal equipment for feeding these oscillations into the lines.
  • Fig. 5 The waveform of the transmitted signal is illustrated diagrammatically in Fig. 5. From this it is; clear that. the marker pulse has a duration or 22 microseconds and occurs at the end of the, eight speech channels; 1. e. the end of the mar er pulse in stead of its beginning marks the da um point in time. Each speech channel pulse has a duration or 4 microseconds when unmodulated; when] modulated by the speech currents its duration; can vary between 1 and 7 microseconds- The leading edge of each speech channelpulse is fixed and the position 01 the rear edge varies with the modulation, as in the system previously de- 1 scribed.
  • the duration of the gaps, separating the various pulses is indicated in the figure audit is clear that any pulse will be separated i'roml its neighbour by a gap of at least 3 microseconds duration.
  • the duration of each cycle is '111 microseconds corresponding to a repetition frequency of 9100 cycles per-second.
  • the pulse generating circuits are shown in Fig. 6. In order to simplify the drawing only one of the eight identical series of valves for generating the speech channel pulses is shown. In general, the operation of these circuitsis similar to that'of the circuits already described with reference to Figs. 2 and 3 the only important. difi'erence being the method of generating the marke pulses.
  • the 9100 cycle repetition frequency is generated by the sine wave oscillator 20, the sinusoidal output 01 which is appliedto the control grid of the marker pulse generator 2
  • the grid 01' the valve 21 is negatively biased so that only the peak of the positive halt-cycle of the applied voltage is effective in removing the cut-off bias and rendering the valve conductive, .the duration of the conductive period being 22 microseconds. Consequently a negative pulse of 22 microseconds duration appears in the. anode,
  • valve 28 is cut off, the condenser 33 charges and then suddenly discharges at the end of the period During this period of 7 microseconds the thus producing in the anode circuit of the valve 23, a positive pulse ofsaw-toothed form lasting jfor.7 microseconds, This pulse is applied tothe gcontrolgrid of the modulator valve 29 and drives the grid positive with respect to the cathode for 1a period the length of which depends upon the cathode potential. In the absence of a'modulating voltage the cathode potential is such that the grid is driven positive for a. period of 4 microseconds.
  • the speech currents for channel I are fed from the incoming line into a conventional hybrid circuit 34, and after amplification by the valve 30 are injected into the cathode circuit of the valve 29 to vary the cathode potential in ac- :cordance with the speech current amplitude.
  • the grid of valve 29 is driven positive for a period varying between 1 and 'l microseconds according to the speech amplitude, and corresponding negative pulses appear in the anode circuit of valve 29.
  • These are fed to the control grid of the common mixer valve 23, together with the outputs of the similar pulse generators for the seven remaining channels.
  • the control grids of the first valvesof these generators are all fed vrith the saw-toothed voltage from the output valve 26 whilst their cathodes are connected to appropriate taps on the potentiometer 4.
  • output of the mixer valve 23 will then consist of a series of positive pulses interlaced in the manner shown in Fig. 5, and after amplification by the valve 35, this output is employed to modulate the amplitude of an ultrahigh frequency carrier generated by the transmitter 36.
  • the separating and demodulating circuits are shown in Fig. 8.
  • the pulse modulated carrier is received by a supersonic-heterodyne receiver 4!,
  • the voltage changes due to the speech channel pulses are insuflicient to swing the control grid positive and consequently the condenser 50 charges until the arrival of a .marker pulse produces a voltage change of sufficient amplitude to render the valve 48 conductive.
  • a saw-toothed voltage which is synchronous with that produced by the valve 22 of Fig. 5, and which starts increasing at the end of amarker pulse and flies back toits original value during the marker pulse.
  • Thiss'awtoothed voltage is fed via the cathode-follower stage 5
  • This valve together with the valve 53 constitute the generator of the stroboscope pulses for the first channel. They operate in manner substantially v the marker pulse.
  • the positive stroboscope pulses in its anode circuit will be square shaped instead of saw-toothed.
  • the timing of. these pulses is arranged to coincide with that of the speech pulses of the first channel by connecting the cathode of valve 52 to the appropriate tap on the potentiometer 40, whilst the width of the pulses is fixed at approximately 9 microseconds by choosing an appropriate setting for the condenser 58.
  • the stroboscope pulses are applied to the inner grid and'the signal pulses from the cathode circuit of valve 43- are applied to the outer grid of the separator valve 54.
  • a signal pulse generator for each channel means for gencrating a periodically recurring triggering voltage the repetition frequency can be divided to produce a, suitable operating frequency for 'synchronous motors at the transmitter and receiver foroperatlng the enciphering and deciphering switches.
  • the system according to the invention the following advantages as compared with multichannel systems depending on the use of tuned filters.
  • the equipment is much lighter and smaller and requires less skill in construction, since, in the main, it uses valves with simplercondenser-resistance coupling networks; Also the circuit constants for each channel are identical,
  • radio transmitting and receiving circuits for transmitting the interlaced pulses over a single link and reproducing them at a receiving point, a selectin impulse generator for each channel Iatfsaidreceiving point, means for generating a synchronism with the correspondingsignal pulse fed with the interlaced signal pulses and with the output of one of said selecting impulse gen- -erators and arranged to, pass one only of the interlaced trains of signal pulses, and an outgoing instead of to the square of the number elf-charinels.
  • a method r transmitting electricali signais from a number of channels over, a single link to a receiving point and there separating'anddistributingthe'm'to an equal number or channels,
  • An electrical signalling system comprising a .pluralityoi incoming signal channels, a signal I a'pu'lse-generator for each channekmeans 'iorgencrating a periodically recurring triggering voltage .arranged to trigger each generator in turn at a 30 ilxedrepetition frequency, :a device associated with each generator for varying the duration "of.
  • the pulsespin accordancewith the amplitude or the signal in the corresponding-channel, a generat'orfor producing-marker pulses of'longer duration'than the sl'gnal pulses -atsaid fixed repetition; "irequencmacommon output circuit in which all theitrains oi'pulsesf-rom all said generators are interlaced,'-radio transmitting and-receiving'circults for'transmittingxtheinterlaced pulses-over a single link and reproducing them at a receiv lug-point, a discriminating circuit for separating said marker pulses from the-interlaced channel pulses,' at said receiving-point, a selectingiimpulse generator foreach channel, means under the controloi 'the separated marker'pulses ior transmitting point a separate train oi' voltage pulses for each channel,- the repetition'irequencyl oi the pulses being the same for all the trains but the timing oi the pulses in eachtra
  • each signal pulse generator includes a-thermionic valve having its cathode potential fixed at a voltage which is positive relative to its grid p tential,- ',this voltage being diflerent for each generator, 'means for applying-the saw-toothed voltage to the grid of all the thermionic valves to causeeach one to conduct in turn. when its changinggrid potential equals its cathode potential, and means for utilizing the sudden conduction to develop a in step therewith and to suppress the remainder,
  • An electrical signalling system comprising a 5. .An electrical signalling system according to claim 2 wherein the device for varying the duration of the signal pulses from each generator comprises a first thermionic valve having a negative bias on its control grid and a condenser connected in shunt therewith, a connection for applying the signal pulses to the control grid of suppressor grid, each negatively biased, means for applying the interlaced signal pulses of positive voltage to one grid and the positive selecting impulses from one generator to the other grid, whereby the valve conducts only when a selecting impulse and a signal pulse are simultaneously present.
  • the device for varying the duration of the signal pulses from each generator comprises a first thermionic valve having a negative bias on its control grid and a condenser connected in shunt therewith, a connection for applying the signal pulses to the control grid of suppressor grid, each negatively biased, means for applying the interlaced signal pulses of positive voltage to one grid and the positive selecting impulses from one generator to the other grid, whereby the valve conducts only
  • An electrical signalling system comprising a plurality of incoming signal channels, a signal pulse generator for each channel, a marker pulse generator, means for generating a first sawtoothed voltage wave having a fixed repetition frequency, a thermionic valve in each generator responsive to said saw-toothedvoltage wave and arranged to conduct at a certain point along the wave which is different for each generator, means in each generator for utilizing the conduction to develop a pulse, means in each signal pulse generator for varying the duration of the pulse in accordance with the instantaneous amplitude of the corresponding signal, an output circuit in 1 which the pulses from all the l interlaced, radio transmitting and receiving cir- 1 cults for transmitting the interlaced pulses over 3 a single link and reproducing them at a receiving 5 point, a discriminating circuit-for separating the marker pulses from the interlaced signal pulses generators are at said receiving point, meansunder the control 01' the separated marker pulses for generating a.
  • a selecting impulse generator for each channel responsive to said second sawtoothed wave and operating in the same manner as the corresponding signal pulse generator to develop impulses of fixed duration in synchronism with the corresponding signal pulses, a selecting circuit for each channel fed with the interlaced pulses and W'iththe selecting impulses from one of said generators and arranged to pass one only of the interlaced trains of pulses, and an outgoing channel for each selecting circuit.
  • An electrical signalling system comprising a plurality of incoming signal channels, a signal pulse generator for each channel, a sine wave oscillator, means controlled by said oscillator for developing a first saw-toothed voltage wave, a marker pulse generator controlled by said oscillator and arranged to develop a pulse during the flyback of said saw-toothed wave, a thermionic valve in each signal pulse generator responsive to said saw-toothed voltage wave and arranged to conduct at-a certain point along the wave which is different for each generator, means in each signal pulse generator for utilizing the conduction to develop a pulse, means in each signal pulse generator for varying the duration of the pulse in accordance with the instantaneous amplitude of the corresponding signal, an output circuit in which the pulses from all the gen erators are interlaced, radio transmitting andat a receiving point, a discriminating circuit for separating the marker pulses from'the interlaced signal pulses at said receiving point, means under the control of the separated marker pulses for generating a second

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Electrotherapy Devices (AREA)
  • Plasma Technology (AREA)
US522350A 1942-12-04 1944-02-14 Multiplex pulse modulation system Expired - Lifetime US2403210A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB17308/42A GB584729A (en) 1942-12-04 1942-12-04 Improvements in or relating to electrical signalling systems

Publications (1)

Publication Number Publication Date
US2403210A true US2403210A (en) 1946-07-02

Family

ID=10092897

Family Applications (1)

Application Number Title Priority Date Filing Date
US522350A Expired - Lifetime US2403210A (en) 1942-12-04 1944-02-14 Multiplex pulse modulation system

Country Status (3)

Country Link
US (1) US2403210A (en, 2012)
FR (1) FR959084A (en, 2012)
GB (1) GB584729A (en, 2012)

Cited By (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2447233A (en) * 1943-04-07 1948-08-17 Standard Telephones Cables Ltd Pulse time modulation multiplex receiver
US2453461A (en) * 1946-06-19 1948-11-09 Bell Telephone Labor Inc Code modulation communication system
US2468703A (en) * 1946-09-26 1949-04-26 Serdex Inc Chronometric electronic radiosonde system
US2469066A (en) * 1946-06-01 1949-05-03 Rca Corp Pulse multiplex receiver
US2489302A (en) * 1944-05-26 1949-11-29 Int Standard Electric Corp Multichannel time modulated electrical pulse communication system
US2490801A (en) * 1946-03-02 1949-12-13 Fed Telecomm Lab Inc Electrical pulse time modulation circuit
US2497411A (en) * 1946-07-25 1950-02-14 Stromberg Carlson Co Pulse transmission system
US2499844A (en) * 1947-01-16 1950-03-07 Philco Corp Receiver for pulse-position-modulation systems
US2509064A (en) * 1945-08-23 1950-05-23 Bell Telephone Labor Inc Reduction of noise in pulse position modulation systems
US2513335A (en) * 1944-11-25 1950-07-04 Standard Telephones Cables Ltd Demodulator system
US2517579A (en) * 1945-12-28 1950-08-08 Int Standard Electric Corp Multichannel pulse receiving system
US2521710A (en) * 1947-05-21 1950-09-12 Int Standard Electric Corp Pulse time demodulator system
US2523279A (en) * 1943-04-07 1950-09-26 Int Standard Electric Corp Multiplex high-frequency electrical pulse signaling system
US2524789A (en) * 1946-07-27 1950-10-10 Standard Telephones Cables Ltd Multichannel time modulated pulse receiving system
US2529564A (en) * 1946-09-17 1950-11-14 Rca Corp Pulse multiplex receiving system
US2531817A (en) * 1945-08-04 1950-11-28 Rca Corp Compensated channel selector
US2532719A (en) * 1944-10-16 1950-12-05 John H Homrighous Dimensional radio communication system
US2535048A (en) * 1944-04-29 1950-12-26 Standard Telephones Cables Ltd Communication and radio guidance system
US2536654A (en) * 1947-01-04 1951-01-02 Rca Corp Pulse multiplex transmission system
US2537991A (en) * 1945-05-14 1951-01-16 Standard Telephones Cables Ltd Pulse multiplex drop channel system
US2541076A (en) * 1944-08-07 1951-02-13 Standard Telephones Cables Ltd Multichannel pulse communicating system
US2541134A (en) * 1943-02-20 1951-02-13 Products & Licensing Corp System for distributing successive electrical impulses to a multiplicity of output channels
US2542991A (en) * 1945-03-01 1951-02-27 Int Standard Electric Corp Pulse modulation communication system
US2546974A (en) * 1941-12-16 1951-04-03 Int Standard Electric Corp Pulse multiplex signaling system
US2548795A (en) * 1947-04-22 1951-04-10 Rca Corp Pulse multiplex system
US2567203A (en) * 1946-02-05 1951-09-11 Marcel J E Golay Multiplex communication system utilizing successive, different pulse modulation techniques
US2588930A (en) * 1947-04-22 1952-03-11 Gen Railway Signal Co Airway traffic control system
US2604592A (en) * 1947-10-21 1952-07-22 Standard Telephones Cables Ltd Pulse demodulator system
US2605360A (en) * 1947-03-10 1952-07-29 Rca Corp Time division multiplex system utilizing a step-wave generator in the distributor circuit
US2616975A (en) * 1947-02-06 1952-11-04 Rca Corp Time division multiplex system
US2628274A (en) * 1944-06-27 1953-02-10 John H Homrighous Multiplex television system
US2643333A (en) * 1945-11-29 1953-06-23 Us Navy Data transmission system
US2657269A (en) * 1947-01-02 1953-10-27 Int Standard Electric Corp Electric pulse modulation system of communication
US2682575A (en) * 1944-10-19 1954-06-29 Bell Telephone Labor Inc Time division multiplex system
US2736007A (en) * 1956-02-21 Teledata system
US2740839A (en) * 1946-04-16 1956-04-03 Int Standard Electric Corp Multiplex electric communication system
US2974281A (en) * 1957-11-01 1961-03-07 Bell Telephone Labor Inc Selective signal recognition system
US3194889A (en) * 1960-12-23 1965-07-13 Itt Time division multiplex system
US3720790A (en) * 1973-01-31 1973-03-13 Amp Inc Data transmitting system
US4396801A (en) * 1946-06-11 1983-08-02 Bell Telephone Laboratories, Incorporated Multiplex communication system employing pulse code modulation

Cited By (40)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2736007A (en) * 1956-02-21 Teledata system
US2546974A (en) * 1941-12-16 1951-04-03 Int Standard Electric Corp Pulse multiplex signaling system
US2541134A (en) * 1943-02-20 1951-02-13 Products & Licensing Corp System for distributing successive electrical impulses to a multiplicity of output channels
US2523279A (en) * 1943-04-07 1950-09-26 Int Standard Electric Corp Multiplex high-frequency electrical pulse signaling system
US2447233A (en) * 1943-04-07 1948-08-17 Standard Telephones Cables Ltd Pulse time modulation multiplex receiver
US2535048A (en) * 1944-04-29 1950-12-26 Standard Telephones Cables Ltd Communication and radio guidance system
US2489302A (en) * 1944-05-26 1949-11-29 Int Standard Electric Corp Multichannel time modulated electrical pulse communication system
US2628274A (en) * 1944-06-27 1953-02-10 John H Homrighous Multiplex television system
US2541076A (en) * 1944-08-07 1951-02-13 Standard Telephones Cables Ltd Multichannel pulse communicating system
US2532719A (en) * 1944-10-16 1950-12-05 John H Homrighous Dimensional radio communication system
US2682575A (en) * 1944-10-19 1954-06-29 Bell Telephone Labor Inc Time division multiplex system
US2513335A (en) * 1944-11-25 1950-07-04 Standard Telephones Cables Ltd Demodulator system
US2542991A (en) * 1945-03-01 1951-02-27 Int Standard Electric Corp Pulse modulation communication system
US2537991A (en) * 1945-05-14 1951-01-16 Standard Telephones Cables Ltd Pulse multiplex drop channel system
US2531817A (en) * 1945-08-04 1950-11-28 Rca Corp Compensated channel selector
US2509064A (en) * 1945-08-23 1950-05-23 Bell Telephone Labor Inc Reduction of noise in pulse position modulation systems
US2643333A (en) * 1945-11-29 1953-06-23 Us Navy Data transmission system
US2517579A (en) * 1945-12-28 1950-08-08 Int Standard Electric Corp Multichannel pulse receiving system
US2567203A (en) * 1946-02-05 1951-09-11 Marcel J E Golay Multiplex communication system utilizing successive, different pulse modulation techniques
US2490801A (en) * 1946-03-02 1949-12-13 Fed Telecomm Lab Inc Electrical pulse time modulation circuit
US2740839A (en) * 1946-04-16 1956-04-03 Int Standard Electric Corp Multiplex electric communication system
US2469066A (en) * 1946-06-01 1949-05-03 Rca Corp Pulse multiplex receiver
US4396801A (en) * 1946-06-11 1983-08-02 Bell Telephone Laboratories, Incorporated Multiplex communication system employing pulse code modulation
US2453461A (en) * 1946-06-19 1948-11-09 Bell Telephone Labor Inc Code modulation communication system
US2497411A (en) * 1946-07-25 1950-02-14 Stromberg Carlson Co Pulse transmission system
US2524789A (en) * 1946-07-27 1950-10-10 Standard Telephones Cables Ltd Multichannel time modulated pulse receiving system
US2529564A (en) * 1946-09-17 1950-11-14 Rca Corp Pulse multiplex receiving system
US2468703A (en) * 1946-09-26 1949-04-26 Serdex Inc Chronometric electronic radiosonde system
US2657269A (en) * 1947-01-02 1953-10-27 Int Standard Electric Corp Electric pulse modulation system of communication
US2536654A (en) * 1947-01-04 1951-01-02 Rca Corp Pulse multiplex transmission system
US2499844A (en) * 1947-01-16 1950-03-07 Philco Corp Receiver for pulse-position-modulation systems
US2616975A (en) * 1947-02-06 1952-11-04 Rca Corp Time division multiplex system
US2605360A (en) * 1947-03-10 1952-07-29 Rca Corp Time division multiplex system utilizing a step-wave generator in the distributor circuit
US2588930A (en) * 1947-04-22 1952-03-11 Gen Railway Signal Co Airway traffic control system
US2548795A (en) * 1947-04-22 1951-04-10 Rca Corp Pulse multiplex system
US2521710A (en) * 1947-05-21 1950-09-12 Int Standard Electric Corp Pulse time demodulator system
US2604592A (en) * 1947-10-21 1952-07-22 Standard Telephones Cables Ltd Pulse demodulator system
US2974281A (en) * 1957-11-01 1961-03-07 Bell Telephone Labor Inc Selective signal recognition system
US3194889A (en) * 1960-12-23 1965-07-13 Itt Time division multiplex system
US3720790A (en) * 1973-01-31 1973-03-13 Amp Inc Data transmitting system

Also Published As

Publication number Publication date
FR959084A (en, 2012) 1950-03-23
GB584729A (en) 1947-01-22

Similar Documents

Publication Publication Date Title
US2403210A (en) Multiplex pulse modulation system
US2199634A (en) Secret communication system
US2497411A (en) Pulse transmission system
US2462111A (en) Multichannel pulse distributor system
US2447233A (en) Pulse time modulation multiplex receiver
US2550821A (en) Combined television and sound system
US2527638A (en) Pulse skip synchronization of pulse transmission systems
US2662116A (en) Double modulated pulse transmission
US2454815A (en) Multichannel pulse communication system employing complex multivibrator modulators
US2489302A (en) Multichannel time modulated electrical pulse communication system
US3484693A (en) Frequency shifted sliding tone sampled data communication system
US2698896A (en) Pulse communication system
US2671130A (en) Combined television and sound system
US2510987A (en) Multiplex time modulated electrical pulse demodulation system
US2860185A (en) Keyed frequency modulation carrier wave systems
US3789148A (en) Multiplex transmission method
US2582968A (en) Electrical pulse secrecy communication system
US2816163A (en) Synchronizing system for signal receivers
US2567203A (en) Multiplex communication system utilizing successive, different pulse modulation techniques
US2480582A (en) Synchronizing pulse gating system
US2491969A (en) Electric signal transmission system
GB630094A (en) Improvements in or relating to signalling systems
US2517579A (en) Multichannel pulse receiving system
US2616977A (en) Sheetsxsheet i
US2519083A (en) Time division pulse multiplex system