US2395467A - Multiplex telephone system - Google Patents

Multiplex telephone system Download PDF

Info

Publication number
US2395467A
US2395467A US506803A US50680343A US2395467A US 2395467 A US2395467 A US 2395467A US 506803 A US506803 A US 506803A US 50680343 A US50680343 A US 50680343A US 2395467 A US2395467 A US 2395467A
Authority
US
United States
Prior art keywords
terminal
pulses
line
channel
energy
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
US506803A
Other languages
English (en)
Inventor
Edmond M Deloraine
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
Priority to BE462299D priority Critical patent/BE462299A/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US506803A priority patent/US2395467A/en
Priority to GB18684/44A priority patent/GB587489A/en
Priority to FR941112D priority patent/FR941112A/fr
Application granted granted Critical
Publication of US2395467A publication Critical patent/US2395467A/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
    • H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
    • H04J3/1676—Time-division multiplex with pulse-position, pulse-interval, or pulse-width modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/14—Relay systems
    • H04B7/15—Active relay systems
    • H04B7/155—Ground-based stations
    • H04B7/17—Ground-based stations employing pulse modulation, e.g. pulse code modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J1/00—Frequency-division multiplex systems
    • 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
    • H04J3/08—Intermediate station arrangements, e.g. for branching, for tapping-off

Definitions

  • This invention relates to multiplex communication systems and more particularly to communicationsystems using time modulated pulses to convey the wanted intelligence.
  • the system may include a pair of terminal stations interconnectedby a common line. At an intermediate' point in the line may be provided an intermediate or branch terminal which may be arranged to communicate with either or both the regular terminals over one or more channels.
  • a power source at one terminal may furnish power at the intermediate terminal and to line repeaters in the line. At the same ⁇ time the energy from the power source may serve to synchronize operation of the transmitter and receiver equipment at the intermediate terminal and the other terminal of the system.
  • the signals may be carried in one direction by simple modulation of pulses, preferably in time, and in the other direction by a carrier frequency wave modulated by the modulated pulses.
  • Figs. l, 2 and 3 taken together, illustrate schematically a complete multi-channel pulse ⁇ coina branch circuit repeater or terminal in ⁇ Fig,2 and the other terminal in Fig, 3. f r
  • Fig. 1 is umstratecii; terminal equipment I0 coupled over line I I and' through a repeater ⁇ I2 to the intermediate or branch terminal equipment I3, 'shown in Fig.2.
  • the intermediate branch terminal I3 is coupled overY line
  • terminal I0 At terminal I0 are shown in full lines three terminal connectors I, 2 and 3 which may be coupled to two-Way transmission voice linesover a selector switch, if desired. Additional .channels may be provided, as indicated bythe dotted .2 and 3 are lcoupled over hybrid coils IUI,
  • an alternating current ⁇ power source which should be well regulated ⁇ to maintain a constant frequency.
  • the ⁇ frequency of tin alternating ⁇ current from :this power source is Ypreferably asubmultiple frequency .of the cadence frequency of the impulses transmitted from mod. ulators
  • the power source may be 3000 cycles. It is clear that lower or higher frequencies for the power source may be provided, if desired.
  • Energy from power source 0 is used tol control synchronizing source l
  • Line II serves as a two-way communication line, the incoming signals to terminal I being supplied by way'of a carrier frequency sufliciently high to carry the signal bearing pulses.
  • I passes over high pass filter III and band pass separating mier
  • 35 serves to detect the impulsesv incoming over line II [and removes the carrier frequency therefrom.
  • 35 are applied to demodulators
  • the proper timing of the demodulators for separating the incoming channels is achieved by energy from synchronizing source II2.
  • This synchronizing energy is passed over a phase shifter II6 and line A
  • v-Fig..2 is shown an intermediate or branch terminal repeater. serving to select one or more of the channels incoming over line II from both directions.
  • line I I are coupled high passi-liter 2I4 and low pass filter 2I5 serving to separate the signal. frequencies and the low frequency power energy from line II.
  • Band pass lters 2 I3 and 2:33 coupled over to separate out energy from terminal I0 and from terminal I respectively.
  • Energy from the output of low pass filter 2I5 is applied tothe rectifier 2IIvwhich, in turn, supplies operating power to demodulator 201,V modulator 221, demodulator 22,8,fmodulator 208, synchronizing oscillator 2I2, and to,other modulators and demodulators, as requiredover lines 210, ergy from the output to synchronireA the operation of synchronizing control oscillator 2I2 which serves to switch into operation the modulators and demodulators in proper sequential order to select the desired transmission channel and to assure application of energy fromthe modulator to line II in proper timed relation for reception at either of the terminals I0 or I5 over lines 260, 26
  • en-V of low pass filter 2 I5 serves high pass lter 2I4 serve e ergy from synchronizing oscillator 2 I 2.
  • shifter 231 is adjusted properly to time the pulses ringing relay 244 is operated, intermittently closing contacts 245, and applying ringing signals to outgoing voice line 246.
  • the demodulated voice signals are passed over high pass filter 24
  • Incoming voice signals over line 246 are applied to hybrid coil 242 which is provided with balancing network 243 and from hence to pulse modulator 221.
  • Pulse modulator 221 is controlled by phase shifter 231 also in turn controlled by en- Phase of ⁇ this channel to t into the return trains of channels for-suitable selection at terminal I0.
  • These pulses from the output of modulator 221 are applied to carrier modulator 235 which serves to provide the carrier frequency for communication to terminal I0.
  • the output from carrier modulator 235 is then applied over band pass filter 233 to line II and hence back over repeater I2 to terminal I0.
  • This carrier energy is then passed over high pass lter II4 and selected by band pass filter
  • the proper signals for channel I are' selected in demodulator
  • phase Shifters 2I1 and 231 may be adjusted by means of a common control 20
  • phase Shifters 2I1 and 231. are preferably made to operate in steps so that each step constitutes substantially the normal time displacement between pulse signal channels.
  • the switching may be made at terminals I, 2 and 3, so that the desired voice line may be connected to a permanent trunking channel for branch terminal I3.
  • the signals selected at the branch terminal also traverse the line to the other terminals but if desired the equipment there may be disabled under control of an operator.
  • rIfhe signals from terminal I0 after passing intermediate or branch terminal I3, may pass over a further repeater I4 and over line II to terminal I 5.
  • the high pass and low pass filters 3I4 and 3I5 which serve to separate the power energy from the incoming pulse signals.
  • the power energy may operate through a synchronizer 334' synchronously to control a local power source 3
  • operating power could be the incoming power signals but it is preferable to provide the local power source 3
  • 0 may be applied directly to the demodulators 301, 308, 309 and modulators 321, 320 and 329 and to group modulator 335.
  • the synchronizing signals from synchronizer 334 may be applied to synchronizing source 3I2 which serves to control the switching into operation of the demodulators and modulators in proper timed relation over phase Shifters 3
  • an additional phase shifter 336 is provided to take care of the difference in transderivecl directly from mission time between the modulator and demodulator groups.
  • the various channels from terminal I are thus selected at terminal I5 and applied over hybrid coils 30
  • voice signals incoming over line 256 are applied to hybrid coil 252 which is also provided with balancing network 253 to modulator 208.
  • Modulator 208 is controlled by phase shifter 2 I 8 to produce the proper 'time spacing for the incoming pulse channel.
  • the modulated impulses are then applied over band pass lter 2
  • the impulses pass over line Ii and repeater I2 to terminal i0.
  • the incoming signals pass over high pass filter
  • lrepeaters I2 and I4 must be arranged suitably to pass not only the impulse energy and the carrier frequency but also the energy from power source H0. Accordingly, these repeaters cannot readily be made as simple pulse repeaters but instead may be straight linear repeaters. In any case it may be desirable to bypass the power energy about repeaters I2 and I4 by means of low pass lters 22 and 23, respectively.
  • 0 serves the double pur- Dose of supplying power at the repeater stations and of synchronizing operation of the terminal equipment at the branch terminals and at the far terminals of the system.
  • a multiplex signaling System comprising rst andl second terminals with a two-way transmis- ⁇ sion system therebetween, each of said terminals having 'a plurality of stations, each station having a transmitting circuit and a receiving circuit, each transmitting circuit ⁇ having means for generation of a train of time modulated pulses representing.
  • control means at said first terminal to control the timing of the transmissionof pulses from stations thereoi ⁇ to sandwich the pulses together with a given timing characteristic between ⁇ successive pulses of the resulting train of channel pulses, means for applying said resultant train of channel pulses and energy from said control means to said transmission system for transmission to said second terminal, means at said second terminal responsive to energy from said control means to control the alignment of the'receiving ⁇ circuitsl thereof with the proper 'channel pulses from said rst terminal, and furtherto control the timing of the transmitting circuits of said second terminal for channel communication back to said first terminal, a branch terminal having one nr more stations each having a transmitting circuit and a receiving circuit, a line junction connecting said branch terminal to said two-way transmission system, and means for placing anyone of said channels of communication in service be tween any station of said first and second terminals and a station of said branch terminal.
  • the means ⁇ for placing any one of said channels of given timing 'characteristic communication in service between any station of said first and second terminals and a station of said branch terminal includes means for determining at the branch terminal the pulse timing of any given channel, and means responsive to energy from said control means to time the transmittingand receiving circuits of a branch station in accordance with the timing of said given channel.
  • a .multiplex 'signaling system Comprising rst'and second terminals with a two-way transmission ⁇ system therebetween, each of saidvterminals having a plurality ofstations, each station having a transmitting circuit and a receiving circuit, eachv transmittingl circuit :having means.
  • a power Source of "alternating current waves at the rst terminal control means at said first terminal timed by said alternating current waves to control the timing of the transmission of pulses from stations thereof to sandwich the pulses together with a given timing characteristic between successive pulses of the resulting train of channel pulses, means for transmitting alternating current waves from said source to said second terminal, means at said second terminal responsive to alternating current waves 'to control the alignment of the receiving circuits thereof with the proper channel pulsesirom said iirst terminal, and further to controlathe timing of ⁇ the transmitting circuits of saidlsecond terminal for channel communication back .to saidl rst terminal, ⁇ a branch terminal :having one or more stations each having a transmitting circuit and a receiving circuit, a line junction connecting said branch terminal tosaid two-'wayftransmission system, means for deriving energy fromfasa-id alternating current Waves to energize-'said
  • a imultiplex signaling system comprising first andsecond terminals with a transmission line therebetween, a plurality of stations at said rst terminal, each station having a transmitting circuit, each transmitting circuit having means 'for generation of a train of time modulated pulses representing one channel of communication, a power source of' alternating current waves at the first terminal for energizing said transmitting circuits, control means at said rst terminal timed by said alternating current waves tocontrol the timing of the transmission of pulses from stations thereof to sandwich the pulses together with a between successive pulses of the resulting train of channel pulses, means for applying said pulses and energy from said source to said transmission line, means at said second terminal responsive to alternating current waves to control the alignment of the receiving circuits thereof with the proper channel pulses from said first terminal, a branch terminal 'having one or morestations each vhaving a transmitting circuit anda receiving circuit, a line junction connecting said branch terminal to said transmission line, means for deriving energy from said alternating current waves to
  • a multiplex signaling system comprising irst and second terminals with a two-Way transmission system therebetween, each of said terminals having a plurality of stations, each station having a transmitting circuit and a receiving circuit, each transmitting circuit having means for generation of a.
  • a multi-channel communication system wherein a plurality of timed pulse trains each representing a separate channel and a power wave are transmitted from a given terminal station over a common medium; a second terminal coupled to said common medium means at said second terminal responsive to said power wave for energizing the circuits at said second terminal, and selector means timed under control of said power wave for selecting a pulse train representing a predetermined channel from said common medium at said second terminal.
  • a multiplex transmitter means means for transmitting a plurality of pulse channels from said energy from a rst terminal comprising a multiple transmitter means and means responsive to said received control wave for timing the transmission of said pulses from said transmitter.
  • a multi-channel communication system wherein a plurality of timed pulse trains each representing a separate channel and a power Wave are transmitted from a given terminal station over a common medium; a second terminal coupled to said common medium, means at said second terminal responsive to said power 'wave for energizing the circuits at said second terminal, and selector means timed under control of said power wave for selecting a pulse train representing a predetermined channel from said common medium at said second terminal, and means for adjusting said selector means to alter the selection of channels.
  • a second terminal coupled to said common medium comprising means for receiving said pulses and said -power wave, means at said second terminal responsive to said power wave for energizing the circuits at said second terminal, means synchronized in response to said power wave for selectively segregatingl 'the pulses representing different received channels, a multiplex transmitter means at said second terminal, means for transmitting a plurality of pulse channels from said transmitter means and means responsive to said received powerwave for timing the transmission of said pulses from said transmitter.

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
US506803A 1943-10-19 1943-10-19 Multiplex telephone system Expired - Lifetime US2395467A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE462299D BE462299A (pt) 1943-10-19
US506803A US2395467A (en) 1943-10-19 1943-10-19 Multiplex telephone system
GB18684/44A GB587489A (en) 1943-10-19 1944-09-29 Multiplex telephone system
FR941112D FR941112A (fr) 1943-10-19 1945-08-02 Système de téléphonie multiplex

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US506803A US2395467A (en) 1943-10-19 1943-10-19 Multiplex telephone system

Publications (1)

Publication Number Publication Date
US2395467A true US2395467A (en) 1946-02-26

Family

ID=24016071

Family Applications (1)

Application Number Title Priority Date Filing Date
US506803A Expired - Lifetime US2395467A (en) 1943-10-19 1943-10-19 Multiplex telephone system

Country Status (4)

Country Link
US (1) US2395467A (pt)
BE (1) BE462299A (pt)
FR (1) FR941112A (pt)
GB (1) GB587489A (pt)

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429608A (en) * 1942-03-12 1947-10-28 Int Standard Electric Corp Multichannel pulse communication system
US2468085A (en) * 1946-08-24 1949-04-26 Fed Telecomm Lab Inc Two-way pulse multichannel system employing cathode-ray tube modulators
US2468703A (en) * 1946-09-26 1949-04-26 Serdex Inc Chronometric electronic radiosonde system
US2472705A (en) * 1944-07-17 1949-06-07 John H Homrighous Time division carrier multiplex telephone system
US2474244A (en) * 1944-05-19 1949-06-28 Standard Telephones Cables Ltd Amplitude modulated time modulated pulse system
US2497411A (en) * 1946-07-25 1950-02-14 Stromberg Carlson Co Pulse transmission system
US2498688A (en) * 1946-06-22 1950-02-28 Fed Telecomm Lab Inc Demodulator and channel separator system
US2517579A (en) * 1945-12-28 1950-08-08 Int Standard Electric Corp Multichannel pulse receiving system
US2520534A (en) * 1945-08-18 1950-08-29 Bell Telephone Labor Inc Multiplex pulse repeater
US2523703A (en) * 1946-06-25 1950-09-26 Research Corp System for transmitting signal modulated pulses
US2524789A (en) * 1946-07-27 1950-10-10 Standard Telephones Cables Ltd Multichannel time modulated pulse receiving system
US2527558A (en) * 1945-12-31 1950-10-31 Int Standard Electric Corp Two-way pulse multiplex communication system
US2541076A (en) * 1944-08-07 1951-02-13 Standard Telephones Cables Ltd Multichannel pulse communicating system
US2541932A (en) * 1948-05-19 1951-02-13 Bell Telephone Labor Inc Multiplex speech interpolation system
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
US2557581A (en) * 1947-02-15 1951-06-19 Rock Ola Mfg Corp Remote control system
US2570207A (en) * 1945-01-03 1951-10-09 Int Standard Electric Corp Synchronizing arrangement for multiplex electrical pulse communication systems
US2587734A (en) * 1947-12-22 1952-03-04 Meguer V Kalfaian Modulator tube and circuits
US2597038A (en) * 1947-11-19 1952-05-20 Int Standard Electric Corp Two-way electric pulse communication system
US2610295A (en) * 1947-10-30 1952-09-09 Bell Telephone Labor Inc Pulse code modulation communication system
US2610254A (en) * 1947-12-07 1952-09-09 Int Standard Electric Corp Mixed modulation in pulse intercommunication systems
US2616977A (en) * 1952-11-04 Sheetsxsheet i
US2627553A (en) * 1946-11-21 1953-02-03 Gen Electric Multichannel signaling system
US2655652A (en) * 1948-06-28 1953-10-13 John H Homrighous Multiplex time division telephone systems
US2658189A (en) * 1948-01-09 1953-11-03 Bell Telephone Labor Inc Signaling system based on orthogonal functions
US2680153A (en) * 1949-01-14 1954-06-01 Philco Corp Multichannel communication system
US2721899A (en) * 1946-07-25 1955-10-25 Gen Dynamics Corp Pulse communication system
US2731512A (en) * 1949-10-26 1956-01-17 Gen Electric Co Ltd Multichannel communication systems
US2736007A (en) * 1956-02-21 Teledata system
US2750566A (en) * 1948-06-04 1956-06-12 Raytheon Mfg Co Telemetering transmission system
US3924074A (en) * 1945-05-19 1975-12-02 Bell Telephone Labor Inc Pulse position modulation key signaling system
US3934078A (en) * 1946-05-01 1976-01-20 Bell Telephone Laboratories, Incorporated Key generating system
US4396801A (en) * 1946-06-11 1983-08-02 Bell Telephone Laboratories, Incorporated Multiplex communication system employing pulse code modulation

Cited By (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2616977A (en) * 1952-11-04 Sheetsxsheet i
US2736007A (en) * 1956-02-21 Teledata system
US2546974A (en) * 1941-12-16 1951-04-03 Int Standard Electric Corp Pulse multiplex signaling system
US2429608A (en) * 1942-03-12 1947-10-28 Int Standard Electric Corp Multichannel pulse communication system
US2474244A (en) * 1944-05-19 1949-06-28 Standard Telephones Cables Ltd Amplitude modulated time modulated pulse system
US2472705A (en) * 1944-07-17 1949-06-07 John H Homrighous Time division carrier multiplex telephone system
US2541076A (en) * 1944-08-07 1951-02-13 Standard Telephones Cables Ltd Multichannel pulse communicating system
US2570207A (en) * 1945-01-03 1951-10-09 Int Standard Electric Corp Synchronizing arrangement for multiplex electrical pulse communication systems
US2542991A (en) * 1945-03-01 1951-02-27 Int Standard Electric Corp Pulse modulation communication system
US3924074A (en) * 1945-05-19 1975-12-02 Bell Telephone Labor Inc Pulse position modulation key signaling system
US2520534A (en) * 1945-08-18 1950-08-29 Bell Telephone Labor Inc Multiplex pulse repeater
US2517579A (en) * 1945-12-28 1950-08-08 Int Standard Electric Corp Multichannel pulse receiving system
US2527558A (en) * 1945-12-31 1950-10-31 Int Standard Electric Corp Two-way pulse multiplex communication system
US3934078A (en) * 1946-05-01 1976-01-20 Bell Telephone Laboratories, Incorporated Key generating system
US4396801A (en) * 1946-06-11 1983-08-02 Bell Telephone Laboratories, Incorporated Multiplex communication system employing pulse code modulation
US2498688A (en) * 1946-06-22 1950-02-28 Fed Telecomm Lab Inc Demodulator and channel separator system
US2523703A (en) * 1946-06-25 1950-09-26 Research Corp System for transmitting signal modulated pulses
US2497411A (en) * 1946-07-25 1950-02-14 Stromberg Carlson Co Pulse transmission system
US2721899A (en) * 1946-07-25 1955-10-25 Gen Dynamics Corp Pulse communication system
US2524789A (en) * 1946-07-27 1950-10-10 Standard Telephones Cables Ltd Multichannel time modulated pulse receiving system
US2468085A (en) * 1946-08-24 1949-04-26 Fed Telecomm Lab Inc Two-way pulse multichannel system employing cathode-ray tube modulators
US2468703A (en) * 1946-09-26 1949-04-26 Serdex Inc Chronometric electronic radiosonde system
US2627553A (en) * 1946-11-21 1953-02-03 Gen Electric Multichannel signaling system
US2557581A (en) * 1947-02-15 1951-06-19 Rock Ola Mfg Corp Remote control system
US2610295A (en) * 1947-10-30 1952-09-09 Bell Telephone Labor Inc Pulse code modulation communication system
US2597038A (en) * 1947-11-19 1952-05-20 Int Standard Electric Corp Two-way electric pulse communication system
US2610254A (en) * 1947-12-07 1952-09-09 Int Standard Electric Corp Mixed modulation in pulse intercommunication systems
US2587734A (en) * 1947-12-22 1952-03-04 Meguer V Kalfaian Modulator tube and circuits
US2658189A (en) * 1948-01-09 1953-11-03 Bell Telephone Labor Inc Signaling system based on orthogonal functions
US2541932A (en) * 1948-05-19 1951-02-13 Bell Telephone Labor Inc Multiplex speech interpolation system
US2750566A (en) * 1948-06-04 1956-06-12 Raytheon Mfg Co Telemetering transmission system
US2655652A (en) * 1948-06-28 1953-10-13 John H Homrighous Multiplex time division telephone systems
US2680153A (en) * 1949-01-14 1954-06-01 Philco Corp Multichannel communication system
US2731512A (en) * 1949-10-26 1956-01-17 Gen Electric Co Ltd Multichannel communication systems

Also Published As

Publication number Publication date
BE462299A (pt)
FR941112A (fr) 1949-01-03
GB587489A (en) 1947-04-28

Similar Documents

Publication Publication Date Title
US2395467A (en) Multiplex telephone system
US2418116A (en) Multiplex synchronizing system
US2414265A (en) Multichannel signaling system using delay line to obtain time division
US3205441A (en) Frequency shift signaling system
US2541076A (en) Multichannel pulse communicating system
US5212578A (en) Selection of transmission facilities using optical wavelength division multiplexing
US2213941A (en) Multiplex signaling by phase discrimination
US2547001A (en) Drop channel pulse multiplex system
US2960573A (en) Electric carrier current communication systems
US2468059A (en) Pulse time modulated multiplex system
US1956397A (en) Multiple channel transmission control
US2423466A (en) Time division multiplex
US3590380A (en) Repeater station for information signals containing pseudo-random auxiliary signals
US2509218A (en) Repeater link system
US2860185A (en) Keyed frequency modulation carrier wave systems
US2912508A (en) Repeater station for a pulse multiplex system
US2457986A (en) Synchronization of time division multiplex communication system
US1854247A (en) Multiplex phase discrimination transmission system
US2527558A (en) Two-way pulse multiplex communication system
US2438902A (en) Pulse multiplex system employing fixed pulse-time displacement for signaling
US3255315A (en) Apparatus for synchronizing stereophonic transmission
US1690299A (en) Generation and control of electric waves
US2513291A (en) Multiplex pulse time demodulator
US5406553A (en) Apparatus and method for converting a frequency division multiplex to a time division multiplex
US3899738A (en) System for measuring group delay and/or attenuation in closed signal-transmission loop