US2485591A - Pulse time division multiplex system - Google Patents

Pulse time division multiplex system Download PDF

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Publication number
US2485591A
US2485591A US625650A US62565045A US2485591A US 2485591 A US2485591 A US 2485591A US 625650 A US625650 A US 625650A US 62565045 A US62565045 A US 62565045A US 2485591 A US2485591 A US 2485591A
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US
United States
Prior art keywords
pulses
synchronizing
pulse
wave
pulse wave
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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
US625650A
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English (en)
Inventor
Donald D Grieg
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.)
STC PLC
Federal Telephone and Radio Corp
Original Assignee
Standard Telephone and Cables PLC
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 Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US625650A priority Critical patent/US2485591A/en
Priority to FR927287D priority patent/FR927287A/fr
Priority to CH281291D priority patent/CH281291A/fr
Priority to BE469507D priority patent/BE469507A/xx
Priority to FR55321D priority patent/FR55321E/fr
Priority to FR57766D priority patent/FR57766E/fr
Application granted granted Critical
Publication of US2485591A publication Critical patent/US2485591A/en
Priority to DEF4324A priority patent/DE938554C/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0602—Systems characterised by the synchronising information used
    • H04J3/0614—Systems characterised by the synchronising information used the synchronising signal being characterised by the amplitude, duration or polarity
    • 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
    • H04J3/045—Distributors with CRT
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/10—Arrangements for reducing cross-talk between channels

Definitions

  • This invention relates to a multichannel communication system. More particularly it deals with a method and means for producing synchronizing pulses along an electromagnetic wave carrying a plurality of signal modulated undulations.
  • synchronizing pulses were distinguished from signal time modulated ⁇ pulses or undulations on a multichannel pulse wave by their width, which was usually constant and greater than that of the substantially instantaneous signal modulated pulses. These synchronizing -pulses were separated 'from multichannel pulse waves by means of a Width discriminator ⁇ and then su-bsequently utilized in establishing the base waves for channel separation, demodulation, and synchronization of return signal channels.
  • width synchronizing pulses have certain disadvantages under practical operating conditions.
  • One disadvantage is that, with some types of repeater equipment, critical adjustment is necessary in order to prevent a cumulative loss of the width characteristic of the synchronizing pulse through decrease in the slopes ⁇ of its leading and trailing edges.
  • Another object is to produce synchronizing pulses of substantially the same shape as the sigpulses on a multichannel pulse wave which are 2 not ⁇ adversely vdistorted Iby repeater equipment, or by diierentiation.
  • Another object is to produce synchronizing pulses on a multichannel pulse wave which are of such a characteristic as to greatly minimize the usual distortion effects of noise.
  • Another object is to separate such a, pair of synchronizing pulses from a multichannel pulse wave in a novel and effective manner.
  • Another object of this invention is to provid-e means for carrying out the previo-us objects.
  • this invention relates to a multichannel communication system having a multichannel pulse wave containing spaced pairs of synchronizing pulses located at intervals between groups .of signal modulated pulses.
  • the multichannel pulse wave may be composed of a plurality of trains of ldifferent signal modulated pulses.
  • Means may be provided for producing a plurality of such signal modulated pulse trains from the same pulse wave source ⁇ and Afor combining the plurality 0f pulse trains on a single multichannel pulse wave wherein the trains of pulses may be interleaved or similarly combined so that the pulses of one -channel will not interfere with those of other channels. It is desirable, that the signal channel modulated puls-es ⁇ are time modulated either with respect to a.
  • the pair of synchronizing pulses of this invention may be produced from Aany pulse sources, but preferably the same source as used for producing the signal modulated pulses.
  • the' pulse wave may be coupled to a suitable reecting delay line to produce two pulses of very short duration and spaced very closely together, usually not further .apart than the two edges of the previously used width synchronizing pulses mentioned above. It is important that the time space between the two Ipulses of the marker pair is less than the space between them and any other Ipulses or between any other pulses in said multichannel pulse wave. This is necessary to readily distinguish the synchronizing pulses from the other or signal modulated pulses on the multichannel pulse waves.
  • the pair of synchronizing pulses have substantially the same shape as :the signal channel modulating pulses.
  • the signal modulated pulses to be synchronized may differ in shape from the synchronizing pulses of this invention, i. e., the synchronizing pulses may be of any desired shape and amplitude. If the ⁇ pulses are only timed displaced on the multichannel pulse wave, both the signal time modulated pulses and the double synchronizing pulses may be shaped to insure sharpness before and/or after being combined on the multichannel pulse wave.
  • Another method for producing the pair of synchronizing pulses may involve a cathode ray device similar to the one disclosed in my joint application, E. Labin et al., Ser. No. 591,065, led April 30, 1945.
  • the synchronizing pulse aperture in the target plate consists of two parallel narrow slits instead of one wide slit as shown in said application.
  • the resulting multichannel pulse wave may be transmitted, repeated and received over suitable communication means such as by radio or by wire, etc.
  • suitable communication means such as by radio or by wire, etc.
  • the pulses thereof may be processed and sharpened such as by a differentlator and clipper, if the pulses are of the same duration as the channel pulses.
  • One method for separating the synchronizing pulses may be to pass them through a suitable trigger circuit to make a width pulse out of each pair (providing there is an even number of pulses in between each pair of synchronizing pulses).
  • the resulting width synchronizing pulses may have their leading edges corresponding to the rst of the pair of the synchronizing pulses vand their trailing edges corresponding to the second of the pair of the synchronizing pulses.
  • These width synchronizing pulses then may be separated by known width discriminating means.
  • Another system for separating the synchronizing pulses is to renect the received multichannel pulse wave in a delay line in which the delay is sui'lcient to cause the first of the synchronizing pair to be superimposed or stacked upon the second of the synchronizing pair of the received pulse wave.
  • This combination of the synchronizv ing pulses produces output pulses of substantially double amplitude, and may be obtained from the pulse train by amplitude discrimination. From the synchronizing pulses thus obtained, suitable deblocking means or phasing means may be operated for separating the channels on the original multichannel pulse wave.
  • the separating and demodulating circuits may be of any suitable design, such as a multivibrator circuit for producing a deblocking wave for separating the pulses, or a cathode ray separating device such as disclosed in my joint copendingapplication, E. Labin et al., Ser. No. 565,152, lled November 25, 1944, now Patent No. 2,465,380, issued March 29, 1949.
  • Fig. l is a schematic wiring diagram of a system for producing multichannel pulse waves containing the double synchronizing pulses of this invention
  • Fig. 2 is a graph of Wave forms useful in explaining the operation of the system of Fig. 1;
  • Fig. 3 is a schematic wiring diagram partially in block of a system for separating the synchronizing pulses from a multichannel pulse Wave of the type produced in the system of Fig. 1 and for separating and demodulating the signal channels on such a multichannel pulse wave;
  • Fig. 4 is a graph of wave forms useful in explaining the operation of the system of Fig. 3;
  • Fig. 5 is a schematic showing of a further embodiment of the invention.
  • the base pulse Wave I may be produced in a suitable pulse wave generator 2 and may be then passed through line 3 to a synchronizing pulse generator circuit 4 and also through line 5 to a suitable system of modulator circuits 6. f
  • the synchronizing pulse generator circuit 4 may comprise a suitable coupler 'I, a delay line 8, and, if desired-a shaper 9, such as a differentiator and/or amplier, or the like.
  • the coupler I may comprise a pentode I0 with suitable circuits to prevent the reiiected pulses from the delayed line 8 from being fed back through the lines 3 and 5.
  • the output from the tube I0 is passed through line II and is joined to the B+ terminal I2 through an impedance I3 across one end of the delay line 8. This .impedance I3 is matched with that of the delay line 8 to prevent distortion and reflection of the reflected pulses.
  • the delay line 8 may comprise a network of inductances and condensers which are coupled in series and parallel respectively, to assimulate a transmission line. It -is important that the end I4 ofthe delay line opposite the impedance I3 be open so that the pulses .are relected without inversion.
  • the reiiected pulses.. together with the pulses of wave I, Fig. 2., are combined at junction vI5 to produce the synchronizing pulse wave I6 comprising a train fof double pulses vI'I and I8.
  • Wave I6 is then passed through line I9, and may be passed through shaper 9, before being withdrawn from the synchronizing pulse generator ⁇ circuit 4 through line 20 to a suitable mixer 2l. As seen from iFig.
  • the first of the pair of pulses I'I. corresponds to the pulses on the wave I while the second pulse L8 ofthe pair of pulses corresponds ,to thedelayed and reiiected train of pulses from the delay line 8.
  • the 'spacing ⁇ between the pair of pulses -IfI and I8 may be very small.
  • the .modulator circuits t may comprise a delay device 22 having taps therea'long .23, 24, and
  • the mixer 2'! should comprise a. suitable device for combining .the trains vof' pulses yfrom the separated pulse channelswa, b,
  • Suitable means for doing this is to provide a parallel network of triodes in which the pulse trains are applied to the grids and the plate circuits are combined.
  • the resulting combined multichannel trains of synchronizing and signal modulated pulses 31 is withrawn through line 38 for transmission.
  • a system for the separation and demodulation of the multichannel pulse Waves produced by the system shown in Fig. l is shown in Figs. 3 and 4.
  • the multichannel pulse wave 31, shown in Fig. 2 may be slightly distorted as shown by the wave 39 in Fig. 4.
  • a suitable processing circuit 4i which may comprise a dilerentiator 42 and a double clipper 43.
  • the differentiator 42 may, comprise a condenser 44 and resistor 45. to the input circuit of the double diode 45 of the double clipper circuit 43.
  • the clipping level line 41 shown in Fig.
  • a suitable sharpened pulse train i comprise a coupler 55, and a delay line 51 coupled thereto in a manner similar to coupler 1 and delay line 8 with one end of the delay line coupled across a matched impedance while the other end is open as shown in Fig. 1.
  • the delay in line 8 is sufcient to cause the second pulse of the pair of synchronizing pulses of Wave 53 to be aligned with the first pulse of the synchronizing pulses of wave 58.
  • 'Fliese two pulse waves 53 and 58 are then combined to produce the pulse wave 59 wherein the two aligned synchronizing pulses above mentioned are superimposed, one upon the other, to produce the increased amplitude pulses 50.
  • Wave 59 is withdrawn through line 6I into a suitable clipper 52 for clipping the pulses 69 from the wave 59 above the line 53 to produce a synchronizing pulse wave 64 which is withdrawn from the clipper through line 65.
  • Wave 64 is a synchronizing pulse wave similar to and in synchronism with the wave I produced in the pulse generator 2 of Fig. 1. With this pulse wave 54, suitable deblocking and separating circuits may be operated for separation of the different channels on the multichannel pulse Wave 53'.
  • One circuit for separating the pulses of the wave 53 may comprise the cathode ray device described in my joint copending application E. Labin et al., Ser. No. 565,152, namelyd November 25, 1944, previously mentioned. A schematic reproduction of such a separating circuit is shown at 66 in Fig. 3. Since this circuit comprises a cathode ray device, the synchronizing pulse wave 64 is passed through a phase wave generator 61 for producing a base wave which in turn is passed through line 58 into a phase shifter and splitter circuit 69 for generating the rotary sweep potentials for the electron beam in the cathode ray tube 10.
  • the energy from the phase shifter and splitter circuit 69 is connected to the vertical and horizontal plates 1l and 12 respectively
  • the differentiator is coupled CFI of tube 10.
  • the time modulated pulses from the pulse wave 53 is withdrawn from processing circuit 4l through line 13 to the grid 14 of the tube 10.
  • the tube also comprises a suitable electron gun 15 and accelerating electrodes 15 for projecting a beam of electrodes between the plates 1l and 12 so that it may be rotated around the path of the separate target plates at the opposite target end of the tube.
  • Each target plate 11, 18, 19, Bil-8i corresponds to a diiierent ,channel a, b, c, d, e, *if* n, respectively.
  • the pair of synchronizing pulses may be produced in a cathode ray device similar to that shown in my joint copending application, Ser. No. 591,065, filed April 30, 1945, Such a cathode.
  • ray device is schematically shown in Fig. 5 of the drawings wherein the device comprises a cathode ray tube 81 having a suitable electrode gun 88, control grid 89 and accelerating electrode 9D, as well as horizontal and vertical deflecting plates 9
  • an aperture plate 93 containing two difierent types of slots, those which are at an angle to the radius of the plate, which are the signal channel modulating slot S4, and the pair of synchronizing slots 95, which are narrow, close together, and substantially radially disposed on the plate 93.
  • the target plate 96 which may be a collector or a secondary omission electrode.
  • a radial delecting electrode 91 having disposed therearound a series of channel deiiecting electrodes 98 corresponding to each signal channel modulating slots 94.
  • the electron beam is deflected radially by the different signal energies applied to the electrodes 98 as it is swept around past each of them and across the slots 94 in the plate 93.
  • the time modulation of the signal channel pulses is measured with respect to the time positions of the synchronizing pulses produced when the rotating electron beam passes over the slots 95.
  • the cathode ray device as shown in Fig. 5 may be employed instead of the modulator circuitv shown. in Fig. 1.
  • a pulse source for delaying ⁇ the pulses from said pulse source, a plurality of sources of signal energy, a plurality of pulse modulators for time modulating pulses from said delay device according t'o said signal energy to produce a plurality of time modulated pulse trains, means to produce a pair of synchronizing pulses of the same polarity spaced at intervals along saidl pulse wave, the spacing between the pulses of said pairv being less than the spacing between any other adjacent pulses on said Wave, and means for combining said pail ⁇ of synchronizing pulses and said trains of signal modulated pulses to produce said multichannel pulse wave.
  • said means for producing said pair of pulses comprises an open circuit reflecting delay line with a balanced impedance at the closed end thereof.
  • a pulse source a delay device for delaying the pulses from said pulse source; a plurality of sources of signal energy, a plurality of pulse modulators for time modulating pulses from said delay device according to said signal energy to produce a plurality of time modulated pulse trains, means to produce a pair of synchronizing' pulses of very short duration and of the saniepolarity spaced at intervals along said pulse wave, the spacing between the pulses of said pair being less than tl're spacing between any other adjacent pulses' on said Wave, means for combining said synchronizing pulses and said trainsof signai modulated ⁇ pulses to produce said multichannel pulse wave, means for transmitting and receiving said pulse wave, means for separating the pair oi synchronizing pulses fram the received pulse Wave, means controlled by the separated synchronizing' pulses' for' separating the different. channels ci; signal energy into separate trains of modulated pulsesand means for de'- mndulating said trains to'repro
  • saidmeans for separating said pairs' of synchronizing. pulses comprises an open circuit reflecting delay line with a balanced impedance lat the closedv end thereof.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Particle Accelerators (AREA)
  • Radar Systems Or Details Thereof (AREA)
US625650A 1945-10-30 1945-10-30 Pulse time division multiplex system Expired - Lifetime US2485591A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US625650A US2485591A (en) 1945-10-30 1945-10-30 Pulse time division multiplex system
FR927287D FR927287A (fr) 1945-10-30 1946-05-23 Perfectionnements aux systèmes de communication à voies multiples
CH281291D CH281291A (fr) 1945-10-30 1946-10-30 Procédé de communication à voies multiples par impulsions.
BE469507D BE469507A (enrdf_load_stackoverflow) 1945-10-30 1946-11-29
FR55321D FR55321E (fr) 1945-10-30 1947-04-04 Perfectionnements aux systèmes de communications à voies multiples
FR57766D FR57766E (fr) 1945-10-30 1947-08-07 Perfectionnements aux systèmes de communication à voies multiples
DEF4324A DE938554C (de) 1945-10-30 1950-10-01 Mehrkanalnachrichtenanlage fuer die UEbertragung zeitmodulierter Signalimpulse

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US625650A US2485591A (en) 1945-10-30 1945-10-30 Pulse time division multiplex system

Publications (1)

Publication Number Publication Date
US2485591A true US2485591A (en) 1949-10-25

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ID=24507003

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Application Number Title Priority Date Filing Date
US625650A Expired - Lifetime US2485591A (en) 1945-10-30 1945-10-30 Pulse time division multiplex system

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US (1) US2485591A (enrdf_load_stackoverflow)
BE (1) BE469507A (enrdf_load_stackoverflow)
CH (1) CH281291A (enrdf_load_stackoverflow)
DE (1) DE938554C (enrdf_load_stackoverflow)
FR (3) FR927287A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2609529A (en) * 1950-01-07 1952-09-02 Fed Telecomm Lab Inc Pulse code translator
US2613318A (en) * 1946-03-26 1952-10-07 Ellery P Snyder Counting down circuit
US2739865A (en) * 1950-04-27 1956-03-27 Servo Corp Of America Electronic recorder
US2786100A (en) * 1950-12-01 1957-03-19 Int Standard Electric Corp Pulse communication systems
US2816169A (en) * 1954-10-25 1957-12-10 Myron G Pawley Multiplex communication system
US2840306A (en) * 1952-11-22 1958-06-24 Digital Control Systems Inc Di-function multiplexers and multipliers
US2872520A (en) * 1952-09-06 1959-02-03 Gen Dynamics Corp Multiplex communication system
US2926217A (en) * 1957-07-05 1960-02-23 Byford Labs Inc Communication system
US2945094A (en) * 1954-09-07 1960-07-12 Itt Pulse signalling system
US3037131A (en) * 1959-03-09 1962-05-29 Motorola Inc Transistor pulse circuit
US3055258A (en) * 1951-08-22 1962-09-25 Hurvitz Hyman Bragg diffraction ultrasonic devices

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2217957A (en) * 1939-05-26 1940-10-15 Hazeltine Corp Wave-signal translating system
US2256336A (en) * 1939-01-06 1941-09-16 Int Standard Electric Corp Pulse modulation system
US2401405A (en) * 1944-05-20 1946-06-04 Rca Corp Method of and means for synchronizing wave generators
US2408077A (en) * 1944-08-25 1946-09-24 Standard Telephones Cables Ltd Multichannel system
US2412974A (en) * 1941-08-29 1946-12-24 Int Standard Electric Corp Electric wave communication system
US2416330A (en) * 1944-08-07 1947-02-25 Standard Telephones Cables Ltd Multichannel receiving system

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE705190C (de) * 1937-02-04 1941-04-19 Telefunken Gmbh Verfahren zum Senden und Empfangen hochfrequenter Impulse
GB491728A (en) * 1937-03-10 1938-09-08 Eric Lawrence Casling White Improvements in or relating to circuit arrangements for separating electric signal pulses
BE428656A (enrdf_load_stackoverflow) * 1937-06-18
FR854646A (fr) * 1939-05-12 1940-04-19 Cfcmug Perfectionnements aux systèmes de communications à distance
BE456799A (enrdf_load_stackoverflow) * 1943-06-21

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2256336A (en) * 1939-01-06 1941-09-16 Int Standard Electric Corp Pulse modulation system
US2217957A (en) * 1939-05-26 1940-10-15 Hazeltine Corp Wave-signal translating system
US2412974A (en) * 1941-08-29 1946-12-24 Int Standard Electric Corp Electric wave communication system
US2401405A (en) * 1944-05-20 1946-06-04 Rca Corp Method of and means for synchronizing wave generators
US2416330A (en) * 1944-08-07 1947-02-25 Standard Telephones Cables Ltd Multichannel receiving system
US2408077A (en) * 1944-08-25 1946-09-24 Standard Telephones Cables Ltd Multichannel system

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2613318A (en) * 1946-03-26 1952-10-07 Ellery P Snyder Counting down circuit
US2609529A (en) * 1950-01-07 1952-09-02 Fed Telecomm Lab Inc Pulse code translator
US2739865A (en) * 1950-04-27 1956-03-27 Servo Corp Of America Electronic recorder
US2786100A (en) * 1950-12-01 1957-03-19 Int Standard Electric Corp Pulse communication systems
US2871290A (en) * 1950-12-01 1959-01-27 Int Standard Electric Corp Electric signal communication systems
US3055258A (en) * 1951-08-22 1962-09-25 Hurvitz Hyman Bragg diffraction ultrasonic devices
US2872520A (en) * 1952-09-06 1959-02-03 Gen Dynamics Corp Multiplex communication system
US2840306A (en) * 1952-11-22 1958-06-24 Digital Control Systems Inc Di-function multiplexers and multipliers
US2945094A (en) * 1954-09-07 1960-07-12 Itt Pulse signalling system
US2816169A (en) * 1954-10-25 1957-12-10 Myron G Pawley Multiplex communication system
US2926217A (en) * 1957-07-05 1960-02-23 Byford Labs Inc Communication system
US3037131A (en) * 1959-03-09 1962-05-29 Motorola Inc Transistor pulse circuit

Also Published As

Publication number Publication date
DE938554C (de) 1956-02-02
FR55321E (fr) 1952-01-02
CH281291A (fr) 1952-02-29
BE469507A (enrdf_load_stackoverflow) 1947-05-29
FR57766E (fr) 1953-09-09
FR927287A (fr) 1947-10-24

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