US2490801A - Electrical pulse time modulation circuit - Google Patents

Electrical pulse time modulation circuit Download PDF

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Publication number
US2490801A
US2490801A US651650A US65165046A US2490801A US 2490801 A US2490801 A US 2490801A US 651650 A US651650 A US 651650A US 65165046 A US65165046 A US 65165046A US 2490801 A US2490801 A US 2490801A
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United States
Prior art keywords
pulses
circuit
wave
pulse
signal
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Expired - Lifetime
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US651650A
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English (en)
Inventor
Donald D Grieg
Arnold M Levine
Moskowitz Sidney
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Federal Telecommunication Laboratories Inc
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Federal Telecommunication Laboratories Inc
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Priority to BE478822D priority Critical patent/BE478822A/xx
Application filed by Federal Telecommunication Laboratories Inc filed Critical Federal Telecommunication Laboratories Inc
Priority to US651650A priority patent/US2490801A/en
Priority to FR950155D priority patent/FR950155A/fr
Priority to ES0182340A priority patent/ES182340A1/es
Application granted granted Critical
Publication of US2490801A publication Critical patent/US2490801A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • 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 pulse time modulation system. More particularly, it deals with a multichannel system for time modulating interleaved trains of pulses with respect to audio or other frequencies' of intelligence.
  • An object of this invention is to time modulate pulses in a simple, novel and effective manner.
  • the pulse time modulation system of this invention comprises the following essential elements: (l) a base wave generator for producing a train of regularly recurring undulations, each of which undulations has a sloping, leading or trailing edge preferably of substantially constant slope; (2) a signal input circuit which may contain a limiter to limit the amplitude of the input signal; (3) a double clipper or gate modulator circuit in which the undulations on the base waveiare clipped along theirl sloping 'edges at different amplitudes corresponding to 'the output from the signal input circuit; and (4) a pulse Shaper circuit for producing time modulated pulses corresponding to the sloping edges 'of the portionsclipped by the gate modulator from the base wave.
  • this system is employed for producing a multichannel pulse wave wherein a plurality of trains of pulses corresponding to different signal channels are interleaved on a separate base waves for each signal channel, means for producing a marker or synchronizing pulse on the multichannel pulse wave so that the diierent channels may be separated therefrom at the receiver, and suitable means for mixing or interleaving the separate trains of pulses corresponding to each signal channel, as well as the train of marker pulses.
  • This latter mixing means may be combined with the Shaper element (4) for mixing the trains of time modulated pulses, and/or a separate mixer means may be provided for mixing the marker pulses with the time modulated pulses.
  • Fig. 1 is a schematic block Wiring diagram of a preferred embodiment of the multichannel time modulation system of this invention.
  • Fig. 2 is a graph of wave forms useful in explaining the operation of the system shown in Fig. 1.
  • I is a base wave generator and a separator circuit from which may be withdrawn one or more base Waves 2, 3, 4 and 5 (see Fig. 2), each of which contains a regular recurring undulation having a sloping edge, the leading edge, for example.
  • base Waves 2, 3, 4 and 5 each of which contains a regular recurring undulation having a sloping edge, the leading edge, for example.
  • Each one of the separate waves 2, 3, 4 and '5 is shown to be reserved for a different signal channel (as indicated in Fig. 2), namely, wave 2 is for the marker or synchronizing channel M, and Waves 3, 4, 5, etc., are for signal channels a, b, c, d. e,
  • the circuit I A may comprise a plurality of separate saw-tooth wave generators or Shapers or each Shaper may be connected to a single Wave generator from which each of the separate channel waves are delayed different amounts so as to be out of phase with each other. This delay may be accomplished by a plurality of taps along a suitable del-ay line or by an electronic distributor means such as a Cyclophon described in the copending application of D. D. Grieg et al., Ser. No. 651,651, filed March 2, 1946.
  • triangular shaped pulses are shown onthe waves 2, 3, 4, 5, any shaped pulse which has a leading or trailing sloping edge, the slope of which is substantially constant on the recurring pulses, could 8, in the double clipper and modulator circuit- 9.
  • the signal to be modulated is also applied to the grid 1 through the audio--input circuitl IIJ coupled to line 6 at the point II.
  • the amount of modulation producedincircuit 9 may be limited by limiting the amplitude of the signal a before it is introduced into the circuit 9. This is particularly advantageous in the case of @multichannel pulse timer... modulation system whereinthe higher amplitude signals often produce ⁇ cross-talk -betweenadjacent channels along the multichannel-gpulse, ⁇ waves.; Thus, by limiting theamplitude ofthe. input signal and thereby the amountAofftimevv modulationY of-'each pulse. the amount of such ⁇ cross-,talkis 4materially reduced.
  • Theflclrclvlitafor limiting this amplitude may comprise a coupling condenser Ilfin the line I5 from the.
  • These.reotiiie rs ,,WandA l'I may comprise.
  • the output from plate 22 of gate modulator tube 8 in line 23 is similar to that shown on wave 24 in Fig. 2.
  • the pulses on this wave 24, for example, correspond to the shaded clipsection 25 from undulation 26 on wave Svafter it has been'amplied to produce the pulse 21 on Wave 24.
  • the important part of this pulse 2 is the time position of its leading edge 28 which corresponds respectively to the portion along the sloping leading edge of the pulse 25 at which the gate ZI clips the pulse 26.
  • the signals applied at point Il from the circuit I0 therefore, moves the gate 2
  • the amplitude signal from the circuit i@ thereby is converted into a time, modulated signal by the double clipper or gate modulator circuit 5 to pro- ⁇ cute the pulse wave 24.
  • the shaper circuit 30 comprises aninductance 3
  • is to diierentiate the wide pulses 21 on wave 24 to produce the positive
  • This inductance 3I in the absence of the rectier 32 would also differentiate the trailing edge of pulse 27 to prof prise the negative pulse 35, shown dotted on Wave 361.k
  • the rectiiier-32 is biased to a B+ voltage supply so that all negative undulations Will be shunted out through the rectifier 32 thereby producing a .waveof vonly positive pulses corresponding in timeA to the leading edges of the pulsesI on Wave 22.*
  • This positive pulse wave may then be withdrawn from the circuit 35i through line 36 to any suitable .utilization circuit, such as in avradio transmitter.
  • line 36 may becoupled to a mixer 31 for mixing it with a marker pulse before it is passed on through line 38 to avtrans-mitter. If the trailing edge ,rather thanthe leading edge of the base wave pulses are to be used, the input to Shaper circuit 30 must be pulses of opposite polarity to those shown on the rectifier. 32 must be reversedto pass only negative pulses tothe commonline circuit.
  • a marker pulse or synchronizing pulse may be produced from Aa separate channel base wavel and stabilized in acircuit similar to that employed for channel a described above. Referring to the ',drawings, then/'ave Zmay .be Withdrawn wave. generatori through line 39 into a ⁇ double clipper ⁇ circuit @similar to 9 except that anxed bias is applied tothe grid? through a .suitable resistance coupled between ⁇ the grid'l in.-
  • Circuit i) also may be. followed. by ashapercircuit 4I which may be identical with the circuit 30 de- -scribed above for shaping the pulses.
  • the output from the shaper 4I. through line 43 would therefore be, similar tothe wave lllvshownVV in Fig.p2 except only the first of the .parir of pulses
  • the wave 2d in line 23- would be present.
  • the synchronizing or marker pulse wave then may be passed into a suitable marker pulse generator circuit 45 which may comprise the delay line for producing the double -pulses as shown on wave 44, or may produce a wider pulse or any other shaped pulse which may be distinguished easily from the time modulated pulses on wave S4.
  • a circuit for producing the double or pair of marker pulses shown on wave 44 is described in the copending case of D. D. Grieg, Serial No. 625,650, led October 30, 1945, now U. S. Patent No. 2,485,591, issued October 25, 1949.
  • wave 44 withdrawn from generator 45 through line 46 may be passed into a suitable mixer 31, which may comprise a pair or more of triodes or other vacuum tubes the plates of which may be coupled together so that the waves 44 and 34 will .be combined to a multichannel wave, such as wave 41 shown in Fig. 2 if only a marker pulse M and signal channel a pulses were shown thereon.
  • a suitable mixer 31 may comprise a pair or more of triodes or other vacuum tubes the plates of which may be coupled together so that the waves 44 and 34 will .be combined to a multichannel wave, such as wave 41 shown in Fig. 2 if only a marker pulse M and signal channel a pulses were shown thereon.
  • signal channels b, c, d n may be modulated in circuits similar to circuits 9 and l@ by passing the wave 4 through line 4B into a suitable double clipper modulator 49 (similar to circuit 9) controlled by output of the limiter circuit 50 (similar to circuit l0) coupled through point El and into which signal b is applied through line 52.
  • a suitable double clipper modulator 49 similar to circuit 9
  • the limiter circuit 50 similar to circuit l0
  • signal b is applied through line 52.
  • From the double clipper modulator i9 for signal b may be withdrawn Wave 53 through line 54 which may be then passed to a shaper similar to shaper 39 or to the same shaper 39 coupled to the modulation circuit for signal channel a as is shown.
  • channel demodulator circuits may be coupled to lines 56 from the base wave generator and separator circuit I to other channel signal input or limiter circuits and other channel double clipper modulator circuits to produce waves 51, etc., and from it waves 58, etc., which are then passed through line 59 coupled to the input of the circuit 30.
  • line 36 is withdrawn a wave similar to 41 shown in Fig. 2 without the marker pulses M.
  • marker pulses may be combined or interleaved With the time modulated pulses in the mixer 31 to produce the wave 41 as shown in Fig. 2.
  • This multichannel pulse wave 41 may be passed through line 38 to any suitable utilization circuits such as a transmitter for transmission by radio or over a cable as desired.
  • a pulse time signal modulation system comprising: a signal source, a signal input circuit to limit the amplitude of the signal from said source; means for producing a train of pulses, each of said pulses having a sloping edge; a double clipper means for clipping the pulses at two levels along their sloping edges at various amplitudes determined by the output from said signal input circuit to produce variable width pulses and means for differentiating said variable width pulses to produce time modulated pulses corresponding to the sloping edges of said portions.
  • the slope of the edges of all of said pulses is substantially the same.
  • a pulse time signal modulation system comprising; a signal source, a signal input ⁇ circuit including two ⁇ biased rectifiers to limit the :peak amplitudes of the signal from said source to a given maximum level; means for producing a train of pulses, each of said pulses having a sloping edge; a double clipper means for clipping the pulses of said train at two levels along their sloping edges at various amplitudes determined .by the output from said limited signal input circuit to produce variable width pulses having a maximum variation determined by said maximum level; and means for di'erentiating said variable width pulses to produce time modulated pulses from the sloping edges of said portions.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Pulse Circuits (AREA)
  • Manipulation Of Pulses (AREA)
US651650A 1946-03-02 1946-03-02 Electrical pulse time modulation circuit Expired - Lifetime US2490801A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE478822D BE478822A (enrdf_load_stackoverflow) 1946-03-02
US651650A US2490801A (en) 1946-03-02 1946-03-02 Electrical pulse time modulation circuit
FR950155D FR950155A (fr) 1946-03-02 1947-07-25 Systèmes de modulation en temps d'impulsions
ES0182340A ES182340A1 (es) 1946-03-02 1948-02-13 MEJORAS EN CIRCUITOS DE MODULACIoN DE IMPULSOS EN TIEMPO

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US651650A US2490801A (en) 1946-03-02 1946-03-02 Electrical pulse time modulation circuit

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US2490801A true US2490801A (en) 1949-12-13

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US651650A Expired - Lifetime US2490801A (en) 1946-03-02 1946-03-02 Electrical pulse time modulation circuit

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US (1) US2490801A (enrdf_load_stackoverflow)
BE (1) BE478822A (enrdf_load_stackoverflow)
ES (1) ES182340A1 (enrdf_load_stackoverflow)
FR (1) FR950155A (enrdf_load_stackoverflow)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2872520A (en) * 1952-09-06 1959-02-03 Gen Dynamics Corp Multiplex communication system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3416717A (en) * 1967-08-15 1968-12-17 Container Corp End closure for lined carton

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2391776A (en) * 1943-05-29 1945-12-25 Rca Corp Intelligence transmission system
US2401384A (en) * 1944-07-17 1946-06-04 Standard Telephones Cables Ltd Television system
US2403210A (en) * 1942-12-04 1946-07-02 Butement William Alan Stewart Multiplex pulse modulation system
US2416329A (en) * 1942-08-24 1947-02-25 Standard Telephones Cables Ltd Push-pull modulation system
US2418116A (en) * 1943-12-20 1947-04-01 Standard Telephones Cables Ltd Multiplex synchronizing system
US2419535A (en) * 1941-11-24 1947-04-29 Standard Telephones Cables Ltd Time-modulated pulse communication system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2419535A (en) * 1941-11-24 1947-04-29 Standard Telephones Cables Ltd Time-modulated pulse communication system
US2416329A (en) * 1942-08-24 1947-02-25 Standard Telephones Cables Ltd Push-pull modulation system
US2403210A (en) * 1942-12-04 1946-07-02 Butement William Alan Stewart Multiplex pulse modulation system
US2391776A (en) * 1943-05-29 1945-12-25 Rca Corp Intelligence transmission system
US2418116A (en) * 1943-12-20 1947-04-01 Standard Telephones Cables Ltd Multiplex synchronizing system
US2401384A (en) * 1944-07-17 1946-06-04 Standard Telephones Cables Ltd Television system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2872520A (en) * 1952-09-06 1959-02-03 Gen Dynamics Corp Multiplex communication system

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Publication number Publication date
FR950155A (fr) 1949-09-20
BE478822A (enrdf_load_stackoverflow)
ES182340A1 (es) 1948-04-01

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