US2468059A - Pulse time modulated multiplex system - Google Patents

Pulse time modulated multiplex system Download PDF

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US2468059A
US2468059A US625649A US62564945A US2468059A US 2468059 A US2468059 A US 2468059A US 625649 A US625649 A US 625649A US 62564945 A US62564945 A US 62564945A US 2468059 A US2468059 A US 2468059A
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pulse
wave
pulses
complex
signal
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US625649A
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Donald D Grieg
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STC PLC
Federal Telephone and Radio Corp
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Standard Telephone and Cables PLC
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems

Definitions

  • This inventidfl relates to a; multichannel cm- Inurllc'atn SYStem fO'f t'reinslrittln'g'Y and receiving a signal inodl'ilatedA cdnplexpulse Wave. More particularly, it deals" ⁇ with the' I'n'ethodV and means for multiplexing trains' of complex pulses'to form a complex' pulsevave in which both a' leading edge andv a trailing edge o'f each complex pulse is tlle rrofleltd ao'cdlllg t0 different signals.
  • Another'olijet is trv'sl't lld receive Such a multiplexed complex oul'sejwave;
  • Another object is tournul'tiple'x trains of such complex pulses( vrtic" lly'v by stacking tvvo' or'more trains of tl'leno'n' tpff each' tl'le to produce single train of step'shapd pulses".
  • Allotlle" Object is t 50th' vertically” and' holzontally multiplex o'f such complex pulses to produce a Single train of step'sha'ped' complex pulses.
  • Anothf olo'jeo't is'to separate and demodulate such r'nl'lltilvle'xed pulse va'ves'.
  • Another object is to time modulate different signals on the edgesof eacl'l coipl'ex'y pulse.
  • Another' object is topovide the' means for carrying out the objects" mentioned alive.
  • the SOllllcs 0f Sig'l'gy which zle rndllated onl tl'e coin'plex pulses" may he vfrom code signals, audio signals, vidosig'nals, Orth-e like.
  • the means fofproduoiiig the trains of complex pulses modulated according tothe energy from said signal sourdes" include es a base Wave source, such as a sine' Wave, savftootl Wave, pulse Wave, or the like, having a constant frequency and at Claims. (Cl. 179-15) least one sloping edge on each pulse or undulation of the Wave. This base Wave then may be clipped along the sloping edge', its undulations at different levels varying in accordance with the energy in a given signal. The resulting train of pulses clipped from' the base vvavel thus are time modulated in accordance with the energy of said signal.
  • a base Wave source such as a sine' Wave, savftootl Wave, pulse Wave, or the like, having a constant frequency and at Claims. (Cl. 179-15) least one sloping edge on each pulse or undulation of the Wave.
  • This base Wave then may be clipped along the s
  • Other trains of pulses, out-of-ph'ase with at least one time' modulated edge of any other pulse train may beproduc'ed by clipping the base Wave at other levels and/or by' delaying the base Wave so' that a delayed base Wave is produced which is out-of-phase with the original base Wave and clipping the resulting delayed hase Wave at the original or' at other levels in accordance with the energy Afrom' another signal.
  • Two pulse trains having time' modulated edges out-of-phase with each other may be combined to ⁇ form a nev'v and complex pulse train in which the leading edge of each pulse thereof is time modulated according to one" signal and the trailing edge of each pulse thereof is time modulated according to another signal channel.
  • Tvvo or more trains of these new complex pulses are then multiplexed to form a single con'plex pulse Wave'.
  • the multiplexing of trainsy of' these complex pulses may .be (l) by vertically stacking one or more pulsesv from diiierent pulse trains to produce a step shaped pulse (each one of the complex pulses having a dilierent Width to permit such stacking) or (2) by horizontally interleaving groups of two or more complex pulse trains the number lo'eing dependent upon the duration of the complex pulse; or (.3) byA both vertically and horizontally multiplexing trains of suchv :conplex pulses.
  • a synchronizing' pulse may be interleaved between the complex' pulses at regularv intervals, such as between each similar group of diiiererlt signal channels.
  • the resulting complex pulse vave having complex pulses multiplexed thereon', may be transinitted and received loyl any suitable high frequency means such as by radio, by Wires or the like.
  • the received multiplexed complex pulse Wave is then separated into pulse trains corresponding to each signal channel transmitted on the complex pulse Wave.
  • Horizontally multiplexed pulses may be separated by providing a blocking Wave to" select only those complex pulses from a given' train' or ⁇ grou'p'of signal channels'.
  • Thefwthus" sep'arratedv complex pulse train is then further separated into pulse ⁇ A trains corresponding to each signal channel thereon, either by clipping means (if the complex pulse is also vertically multiplexed) and/or by differentiating means to separate the leading edges from the trailing edges of each complex pulse.
  • clipping means if the complex pulse is also vertically multiplexed
  • differentiating means to separate the leading edges from the trailing edges of each complex pulse.
  • the vertically multiplexed, or step shaped pulses may rst be separated by clipping means before being horizontally separated by a suitable blocking wave.
  • Fig. l is a schematic wiring diagram partially in block of one embodiment for producing a vertically multiplexed complex wave of this invention
  • Fig. 2 is a graph of the wave forms useful in describing the operation of the system of Fig. 1;
  • Fig. 3 is a schematic wiring diagram of another system for producing a vertically multiplexed complex wave similar to that produced by the system of Fig. 1;
  • Fig. 4 is a graph of the wave forms useful in describing the operation of the system of Fig. 3;
  • Fig. 5 is a schematic wiring diagram mostly in block of a system for separating and demodulating a vertically multiplexed wave produced according to the system of Fig. 1 or 3;
  • Fig. 6 is a graph of the wave forms useful in describing the operation of the system of Fig. 5;
  • Fig. 7 is a schematic block wiring diagram of a system for producing a horizontally multiplexed complex pulse wave
  • Fig. 8 is a graph of the wave forms useful in describing the operation of the system of Fig. 7;
  • Fig. 9 is a schematic wiring diagram partially in block of a system for separating and demodulating the complex pulse wave produced in the system of Fig. 7;
  • Fig. 10 is a graph of the wave forms useful in describing the operation of the system of Fig. 9;
  • Fig. 11 is a schematic block wiring diagram of a system for producing a vertically and horizontally multiplexed complex pulse wave
  • Fig. 12 is a graph of the wave forms useful in describing the operation of the system of Fig. 11;
  • Fig. 13 is a schematic wiring diagram partially in block of a system for separating and demodulating the complex wave produced in the system of Fig. 11;
  • Fig. 14 is a graph of wave forms useful in describing the operation of the system of Fig. 13.
  • Chapter I illustrated in Figs. 1-6
  • Chapter II illustrated in Figs. 7-10
  • Chapter III illustrated in Figs. 11-14, discloses a vertical and horizontal multiplexing system.
  • CHAPTER I Vertical multiplexing system Referring to Figs. 1 and 2, there is shown a base Wave generator I for producing a base wave such as the sine wave 2, which is connected through lines 3 to a modulator clipper 4 which clips a segment 5 out of a sine wave 2 between limits 6 in accordance with the energy in the signal a introduced through the line I into the modulator clipper 4.
  • the clipped segment producing the pulse train 8 is then passed through line 9 to the differentiator clipper I8 and thence to the mixer II.
  • the details of the modulator clipper 4 and differentiator clipper IEB are shown in connection with the circuit for modulating sig- 'nal b below.
  • the edges of the pulses I2 on pulse train 8 vary toward and away from each other in accordance with the signal energy a, i. e., the edges of the pulses I2 are time modulated according to the energy in signal a.
  • the pulses multiplexed in the system of this invention are complex, i. e., having a different signal modulated on the leading edge from that of the trailing edge, only one edge of the pulse I2 is needed in producing the complex pulse. Therefore, the leading edge of pulse I2 is separated from the trailing edge thereof, by differentiating the pulse train 8 to produce the differentiated pulse train I3 wherein only the leading edges of the pulses I2 appear as positive pulses Ill. These pulses Ill are removed from the rest of the train I3 by clipping it along the line I5.
  • the clipping level limits 6 of the different signals may be varied within, different voltage ranges along the sloping edge of the wave, as shown and described later in Fig. 4 or the phase of the base wave may be changed and the clipping may take pulses at the same levels 6 as shown in Fig. 2.
  • the base wave from the generator I is passed through line I6 to the delay mechanism, such as the phase shifter I'I comprising a condenser 8 or a variable resistor I9, to produce the delayed base wave 26 shown in dotted lines in Fig. 2.
  • the delay mechanism such as the phase shifter I'I comprising a condenser 8 or a variable resistor I9
  • the wave 2t is shown delayed an amount so that the leading edge of a pulse train clipped therefrom is in synchronism with the trailing edge of the p ulse train of the original base wave no overlap occurs because only the leading edges of each clipped pulse train are used.
  • Such a delay is not necessary lprovided there is no overlap between the time modulated signal channels of the different signals a. and b.
  • the delayed base wave 2S then passes through line 2
  • the signal b is then connected to transformer 24 through line 25 and its energy varies the level of the clipping segment 5 between the limits 6.
  • the width of the segment 5 is determined by the adjustment of the variable resistors 26 and 2l.
  • From the plate 28 of the tube 23 is withdrawn the clipped pulse train 29 having pulses 28u. with leading and trailing edges time modulated in accordance with the signal b.
  • This pulse train 29 then passes through line 30 to a diiferentiator clipper 3l, which may comprise a diiferentiator circuit consisting of condenser 32 and resistor 33, for producing the differentiated pulse train 34.
  • Diiferentiated pulse train 34 isthen passed on to one of the grids of the clipper tube 35 which is biased through the resistor 33 so as to pass only the positive pulses 36 of the differentiated pulse trains S4 by clipping them olf along the line 3l. These Ipositive pulses 36 are then withdrawn from the plate of tube 35 through the line 38 into the mixer II.
  • the mixer may comprise two triodes 39,:the grids of which are coupled-in parallel with :the lines from the differentiator clippers l and 3
  • the train .40 ⁇ is passed to a trigger circuit 42 from which is withdrawn the complex pulse train 43 through line 44.
  • the trigger circuit 42 may comprise .a pair of triodes ⁇ 45 .coupled in such a manner that an'odd numbered pulse causes one of the tubes to nre aneven numbered pulse fires the other tube'which then remains conductive until the next odd numbered pulse fires the first tube again, and so on.
  • this circuit produces the complex wave 43, which then is. passed through line 441 to the mixer45.
  • Signals c and d may be similarlymodulated on further delayed base waves 41 and 48 respectively, produced from the base wave 2 in phase Shifters 49 and 50 connected to generator
  • These delayed waves ,41 and 48 are modulated and clipped in circuits and 5,2 (similar to circuit 22) from the energy of signals c and d introduced through linesr 53. and 5'4, respectively.
  • From the modulator clippers 5t and 52A are ⁇ withdrawn pulse trains 55 and 56 which are separately differentiated and.v clipped in circuits 51 and'. 58 (similar to. differentiatorf clipper circuit 3
  • These pulses 59 and 60 are mixed in a mixer 0
  • a trigger circuit 83 (similar to 42) -to produce the complex .pulse train 64 which passes to the mixer 45, (similar tothe mixer It). From the mixer 46 isvwithdrawn ⁇ a vertically multiplexed complex step shaped pulse wave 65 through line 65 for transmission by a suitable ultra frequency apparatus.
  • a trigger circuit 83 similar to 42
  • the mixer 45 passes to the mixer 45, (similar tothe mixer It).
  • From the mixer 46 isvwithdrawn ⁇ a vertically multiplexed complex step shaped pulse wave 65 through line 65 for transmission by a suitable ultra frequency apparatus.
  • pulsetrain from pulse lator iclipped to form pulse trains Ahaving rtimed modulated pulses.
  • ⁇ Leading edge wave shaper 10 produces from the base pulse wave 68 inverted wave 12 having pulses or undulations with a leading sloping edge 13 through themeans of a tube 14 and condenser 15. .
  • the shaped base wave 12 is then connected through line 18 to a network of modulator clippers 11, 18 and 19 (similar to modulator clipper 22 shown in Fig. 1) wherein the wave 12 is modulator clipped Vat the different channel levels shown in Fig. 4 to produce pulse trains having time modulated leading edges only (since trailing edge 8
  • the resulting pulse trains (not shown) are separately passed to the mixer 89 (similar to'mixer shown in Fig. 1).
  • comprises a delay device 83, a phase inverter 84, and a differentiator clipper .85.
  • the delay device 83 may comprise a network of inductances and condensers to yassimilate the transmission line.
  • the phase inverter 84 may comprise a triode 80, from the plate of which is withdrawn the delayed and inverted pulse wave 81 through line 88. This wave 81 is thenpassed to the danderrentiator.
  • clipper 85 (similar to 3
  • Wave 89 is then clipped along the line 90 in the tube 85a, to produce a second shaped base wave of positive undulations having vertical leading edges 9
  • pulse trains (not shown) corresponding, respectively, to signals d, e and f introduced into these modulator clippers, (also similar to the modulator clipper 22).
  • the separate pulse trains are then passed into the mixer 80 from which is withdrawn, through line 91 for transmission, a vertically multiplexed complex step shaped pulse wave 98 similar to the wave 65.
  • Figs. 5 and 6 a system for separating and demodulating a vertically multiplexed complex step shaped pulse wave of the type produced in the system of Fig. 1 or 3.
  • Such a complex wave is shown again in Fig. 6 at 99, which is received over line
  • each clipped step comprises a complex pulse train (such as train
  • 03 are then respectively passed to the diiierentiators
  • 104 is shown at
  • the diierentiated pulsetrains are then slipped to remove the positive pulses corresponding to signal channel a, c and e in clippers
  • 01 are passed through the phase inverters
  • the pulse time demodulators may include a harmonic generator
  • CHAPTER II Horizontal multiplexing system In Figs. 7 and 8 is shown a system for horizontally multiplexing a series of complex pulses in which each pulse has one signal modulated on its leading edge and another signal modulated on its trailing edge.
  • This system comprises a base wave generator
  • the signals to be transmitted are modulated from different delayed base waves out-of-phase with the wave
  • These different delayed base Waves are produced from the series of delay devices
  • the base waves are then modulator clipped, respectively according to signals a, b, c, d, e and f in modulator clippers
  • Figs. 9 and 10 disclose a system for separating and demodulatingthe signals on a horizontally multiplexed complex pulse Wave of the type of
  • the pulse width selector 11 (similar to that disclosed in my copending joint application Ser. No. 487,072, led May 15, 1943, U. S. Patent No. 2,440,278, granted April 27, 1948) separates the synchronizing pulses S on Wave
  • This pulse width selector may comprise an amplifying tube
  • 82 are damped through damping tube
  • 81 may comprise two tubes
  • 86 is then withdrawn through line
  • the resulting delayed blocking Waves withdrawn from the delay devices are then respectively coupled to pulse trainselectors
  • the mixer clipper circuit may comprise two triodes
  • This selected complex pulse train is then withdrawn through line 200 and passed through the diierentiator 20
  • the resulting separated signal channels are pulse time demodulatedto reproduce the signals a and b withdrawn through lines 206 and 201, respectively.
  • 18 is the same as that disclosed for the separation and demodulation of the complex pulses described in Fig. above and will be referred to hereinafter as a channel separator and demodulator circuit.
  • 80 and the channels thereon are separated and demodulated in the channel separator and demodulator circuits 209, 2
  • Other pulse trains may be selected in a similar manner and connected to lines 2 I 5, and 2
  • the vertically multiplexed step Ishaped complex pulses produced by the systems disclosed in Chapter I may also be horizontally multiplexed according to the system In Figs. 11 and 12 there is shown such a system comprising a base wave generator 2
  • the vertical multiplexing circuits may be similar to those disclosed in Fig. 1 or Fig. 3 above.
  • 8 is also passed through line 224 to a suitable delay device 225 from which is withdrawn the delayed base wave 226, which is then connected to group II vertical multiplexing circuits 221 from which is withdrawn a vertically multiplexed pulse wave 228 which is passed through line 229 of the mixer 223. Still other delay devices and vertical multiplexing circuits may be connected to line 230 to produce other then connected to the mixer 223. From mixer 223 is withdrawn the resulting vertically and horizontally multiplexed complex pulse wave 23
  • Figs. 13 and 14 is shown a system for separating the channels on a ⁇ complex pulse wave oi' the type ⁇ shown at 23
  • a wave is passed through line 232 and connected both to a blocking wave circuit 233 and to groups I, II and III, etc., separator circuits 234, 235, 236, etc.
  • This system does not disclose the use of a synchronizing pulse for separating similar groups of complex pulses as described in the system of Chapter II, but instead discloses a circuit whereby a blocking wave may be produced directly from the complex pulses on the wave 23 I.
  • the blocking Wave circuit 233 ' consists of a high-Qcircuit 231, a variable sine wave phaser 238, a double clipper 239, a differentiator 240, and a multivibrator circuit 24
  • the high-Q- circuit 231 may comprise a tube 242 and a time constant circuit 243 for smoothing out the sharp corners on the wave 23
  • the variable sine wave phaser is so adjusted that the leading edge of each positive undulation on the Waves 241 and 250are in synchronism with 4the group pulse waves which arek disclosed in Chapter II.
  • the double diode 249 also may act as an amplifier as Well as a clipper for clipping off the round ends of the wave 241 and thereby produce the rectangular shaped Wave 250 which is withdrawn from theplate 25
  • the resistors 253 and 254 may be adjusted and biased to aid in shaping the square wave 256. rIhe wave 250 is then passed to the difierentiator circuit 240 from which is withdrawn the pulse wave 256.
  • This pulse wave is then passed into the multivibrator circuit 24
  • This multivibrator circuit is similar to the multivibrator circuit
  • the blocking wave 251 is then passed through line 26
  • the wave 262 is produced and clipped along the line 263 to separate the cornplex vertically multiplexed pulses 264 of group I. These pulses 264 are then passed through line 265 to the group I channel separator and demodulator circuits 266 similar to those previously described and from which are withdrawn the reproducedr signals a, b, c, d, etc.
  • the group II separator circuits 235 comprises, in addition-to a mixer clipper 261, a delay device 268 for delaying the blocking wave 261 to produce the delayed blocking wave 269.
  • This delayed wave 269 is mixed in the mixer clipper v251 to produce the Wave 210 which is clipped along the line ⁇ 21
  • the resulting clipped pulses 212 are then passed through line 213 to the group II channel separator and demodulator circuits 214 which may be similar to those of 256 and from which are withdrawn the reproduced signals e, f, c, h. etc.
  • Group III separator 236 is similar to the group II separator 235 and the group III channel separator and demodulator circuits 215 are similar to those of group I at 266 lor group II at 214. Still further, group separator and demodulator circuits may be connected to the lines 216 and 211, if desired.
  • the foregoing systems may be extended to multiplex channels other than those specifically shown, provided a sulcient free .space is maintainedV between each of the signal channels to avoid cross talk from one signal channel to the other. This applies both to the vertical multiplexing and to horizontal multiplexing of vthe time modulated edges of the complex pulsesA produced by the systems of this invention and my copending application, Serial No. 614,019, led September ⁇ 1, 1945.
  • a multichannel system means to produce a pulse having vertically disposed portions yof different Widths and means to time modulate the leading edge with one signal and the trailing edge with another signal of each such portions.
  • a system for multiplexing signal modulated pulses to produce a complex pulse wave wherein each pulse carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: at least two sources of signal energy, means to produce a plurality of pulse trains respectively time modulated with energy from said signal sources, said pulses being out-of-phase ⁇ with each other, means to combine two pulses from diierent pulse trains to form a single new pulse train, and means to multiplex a plurality of said new pulse trains to produce said complex pulse wave.
  • the means for multiplexing includes means to superimpose the pulses of said new pulse trains to produce a step shaped pulse on said complex pulse wave.
  • the means for multiplexing includes means to interleave the pulses of said new pulse trains on said complex pulse wave.
  • the means for multiplexing includes means to superimpose the pulses of said new pulse trains to produce step shaped pulses and means to interleave said step shaped pulses on said complex pulse wave.
  • said means for producing a plurality of pulse trains includes means to produce a base wave having a sloping edge, and means to clip said base wave along said sloping edge at various levels corresponding to the energy from said signal sources.
  • the means for producing a plurality of pulse trains includes a base wave source, and means to produce two similar waves, out-of-phase with each other, from said base wave.
  • a system for multiplexing signal modulated pulses to produce a complex pulse wave wherein each pulse carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: at least two sources of signal energy, a base wave source, means to change the phase of said base wave, means to produce pulse trains from the original base wave and the base waves out-of-phase with the original base wave, means for respectively modulating the pulses of said trains with energy from said signal sources, means to interleave the pulses of said pulse trains to produce a new pulse wave means to combine successive pairs of pulses on said new pulse wave to form a series of single pulses each bearing two modulated signal channels, and means to multiplex a plurality of the resulting new pulse waves to produce said complex pulse wave.
  • said means to produce one of said pulse trains includes a diierentiating means and a clipping means.
  • a system for multiplexing'signal modulated pulses to produce a complex pulse wave wherein each pulse carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: at least two sources of signal energy,
  • said means to produce a plurality of pulse trains includes a base wave source, means for separating said base wave to produce two base pulse waves one of which has pulses with a sloping leading edge and the other of which has pulses with a sloping trailing edge, said base pulse waves being outof-phase with each other.
  • a communication system for transmitting and receiving a complex pulse wave having more than two signal channels modulated thereon comprising: more than two sources of signal energy, means to produce a plurality of pulse trains respectively time modulated with energy from said signal sources, said pulses being out-ofphase with each other, means to interleave the pulses of said pulse trains to produce a, new pulse wave, means to combine successive pairs of pulses in said new pulse waves to form a series of single pulses each bearing two signals, means to multiplex a plurality of the resulting combining pulse waves to produce a complex pulse wave wherein each pulse carries at least one time modulated signal in a leading edge thereof and another time modulated signal on the trailing edge thereof, means to transmit said complex pulse wave, means to receive the complex pulse wave, means to separate said complex pulse wave into pulse trains corresponding to each of said signals modulated thereon, and means for demodulating each of said pulse trains.
  • said means for multiplexing includes means to superimpose the pulses of said new pulse trains to produce a step shaped pulse on said complex pulse wave.
  • the means for multiplexing includes means to interleave the pulses of said new pulse train on said complex pulse wave.
  • said means for multiplexing includes means to superimpose the pulses of said new pulse trains to produce step shaped pulses and means to interleave said step shaped pulses on said complex pulse wave.
  • a communicating system for transmitting and receiving a complex pulse wave having horizontally multiplexed pulses thereon wherein each of said pulses carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: more than two sources of signal energy, a base wave source, means controlled by said base wave to produce a synchronizing pulse, means controlled by said base wave to produce a plurality of pulse trains respectively time modulated with energy from said signals, all the edges of said pulses produced from said base wave being out-of-phase with each other, means to combine two pulses from ⁇ dilerent pulse trains to form a single new pulse train, means to horizontally multiplex a plurality of said new pulse trains to produce a complex pulse wave having a synchronizing pulse interleaved at regular intervals between the complex pulses thereon,
  • means to transmit said complex pulse wave means to receive said complex pulse wave, means to separate the signals modulated on said complex pulse Wave comprising a blocking wave controlled by the synchronizing pulse on said complex pulse wave, means for separating the signal channels on the separated pulses to produce pulse trains corresponding to each signal carried by said complex pulse wave, and separate means to demodulate each of said separated pulse trains.
  • a method of communicating a complex pulse Wave carrying a plurality of multiplexed time modulated signals, wherein each pulse on said wave carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: producing a plurality of pulse trains respectively time modulated with energy from said signals, said pulses being out-of-phase with each other, combining two pulses from different pulse trains to form a single new pulse train, multiplexing a plurality of said new pulse trains to produce said complex pulse wave, transmitting said complex pulse wave, receiving said complex pulse wave separating the signals on said received complex pulse wave into separate pulse trains corresponding to each of said signals, and separately demodulating said separated pulse trains to reproduce said signals.
  • a communication system for receiving a complex pulse wave having multiplexed complex pulses thereon, said complex pulses having one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof, said complex pulses being horizontally multiplexed in an interleaved manner, means for separating the wave into pulse trains corresponding to each signal modulated on said complex wave, said separating means including means for producing a blocking Wave having the same frequency as a given train of complex pulses to separate a given pair of signal channels, and means for separating said separated pairs of signals comprising diierentiating means, and means for demodulating each of said separated pairs of signals.
  • a communication system for receiving a complex pulse Wave having multiplexed complex pulses thereon, said complex pulses having one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof, said complex pulses being both vertically and horizontally multiplexed on said complex pulse wave, means for separating the wave into pulse trains corresponding to each signal modulated on said complex Wave, said separating means including a blocking wave for separating the horizontally multiplexed complex pulses, a clipping means for separating the vertically multiplexed pulses, and a diierentiating means for separating the leading edge from the trailing edge of the pulses of the resulting separated pulse train to thereby separate the signal channels, and means for demodulating each of said separated edges to reproduce the signal.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Time-Division Multiplex Systems (AREA)
  • Small-Scale Networks (AREA)
  • Selective Calling Equipment (AREA)

Description

April 26, 1949. I?. DQ GRIEG 2,468,059
PULSE TIME MODULATED MULTIPLEX SYSTEM Filed Oct. 30,' 1945 7 Sheets-Sheet l I A Hz BASE wAvE GENERATOR 7`;|NAL a (4 a 3, MOOULATOR o DF'gf' CLIPPER cLIRPER SIGNAL c ,4r 53 5I 5I F a PHASE MOOULATOR D'Fg ,6| SI-IIFrER cLIPRER CLIPPER M 5( TRIGGER SIGNAL d E @.RCU'T fsc 54 52 se R PHASE MODULA mnqrl FROM OTHER SIGNAL SYSTEMS sI-IIFTER cLIPRER cLIPPER x I TO OTHER SIGNAL SYSTEMS FIG. I
ATTORNEY April 26, 1949. D. DL GRIEG l `ULSE TIME MODULATED MULTIPLEX SYSTEM '7 Sheets-Sheet 2 Filed Oct. 30, 1945 NGE mm Tl Nm m mD D A N O D aux-2 A TTORNEV April 26,y 1949.
Filed OCI.4 30,V 1945.
FROM RECEIVER lOl loo
\ CHANN EL CLIPPER CHANNEL c ld. CLIPPER CHANNEL c 'F CLIPPER 05 DIFFEREN IATOR DIFFERENT IATOR 07 DI FFEREN IATOR FIG. 5
D. D. GRIEG PULSE TIME IIIODULIATED MULTIPLEX SYSTEM IGNAL a.
IMODULATOR l cLI PP E R -I ao SIGNAL b Monu ATon cLIPPER IGNALE 78 MoDuLAToR CLIPPER E GNALy 94 R SIGNAL 'F 95 MoDuLAToR l cLIPPER 97 IGNALI "9 x 1,
To TRANSMITTER MODULATOR CLIPFER MODULATOR C LI PPER PHASE INVERTER CLIPPER CLIPPER IIE 22 PULSE TIME [I IA PHASE INVERTER IIC I2 PULSE TIME DEMoDULATo SGNA'- III |25 PULSE TIME Cl" PPER DEMoDuLAToR SIGNAL PHASE INVERTER IIe as PULSE TIME CLPPER DEMoDuLAToR ")SIGNAI- 4 IN VEN TOR. DONALD D. GRI EG A T'TORNEI/ April 2 6, 1949.
Filed oct. :5o. .1945
'7' Sheets-Sheet 4 R M I x E R M -H-I U I LI I@ P m u n. a o m A RT w RT HRT R El El El R I GU GU GU E Gc. Gc Gc G m mm mm ma m Tc T.c Tc m w 7 .Ib .m MIXER MIXER `IMIXER O M r m I R. s R w m e F o 5 T M T T T.. T 3 MR lR AR MR MR MR I, TE TE ne TE TE IE NP NP NP NP NP NP EP EP EP EP EP EP RH. RI RI RI RU RU EC EL EL EL EC EC F FC FC FC F F, u .u F. W W w D D D D D D 5 5. ,l IM l, ...non IRR vIR lR 3 0 O 3 Tm. TW TW TE ,TH TE R Mp mp. MP up P up BE uw um Uw.. um um. um UP DL DL DL DL DL DL Om 0c oc OC `0 OC OC DI. M M M M. ..M M C u. c d F L L L L L A A A. A N N M N N M w m m m m s w s s s s m D w 2 .r 1. l u ER 3 3 w 4 4 E 1 No I A I M MD T YE E E IR wm @L mm a SE EH Ev Rv HV T Am DD DM DN. DM O BG o INVENTOR. DONALD D. GRIEG A TToR/vgy '7 sheets-sheet 5 I DELAY DEVICE |93 --I PULSE TIME al. DEMODULATOR oIe l *t 2o;
DELAY DEVICE PULSE TIME DEMODU LATOR PULSE TIME DEMODULATOR cLIPPER PuLsE TIME l'l'wed-VDEMODULATDR D. D. GRIEG PULSE TIME MODULATED MULTIPLEX SYSTEM PHASE DIFFER- ENTIAT- OR PULSE r 209 TRAIN l SELECTOR I a DIFFER- ENTIATDR l L April '26, 1949.
Filed OCI. 5o, 1945 IF RDM RECEIVER `2I\| I-EI'cL IZ DELAY DEVICE |96 PULSE TIME DEMODULTOR zIa PULSE TIME DEMODULATOR CLIPPED LEVEL INVENTOR. DONALD D. GRIEG BY ATTORNEY MINDER PHASE DIFFER- ENTIATDR TIME PU LSE TRAIN SELECTOR CHAN NEL NUMBERSI RECEIVED WAVE To OTHER MIXER cLIPPERs WIDTH sELEc'TED MULTI-VIBRAToR-..
DELAYED MIxED a cLIPRER.-
DIFFERENTIATED E CLIPPED April 26, 1949. D, D, GRIEG I 2,468,059
PULSE TIME MODULATED IVIULTIPLEX vSYSTEM Filed OGI.. l150, 1945 '7 Sheets-Sheet 6 +21 L234 239 f2 40 fail F OM' l I RECEIVER 24 2145 23a II I 242 243 l E 233 l f I l y GROUP 1 MIXER CHANNEL c d CLIPPER 265 sEPARATOR a La 4 DEMODULA'roRs V--P-i---f---P--- 214 I I' l GROUP 1r ip I DELAY MIXER l CHANNEL .9h I DEVICE CLIPPER sEPARAToR a l 6B :273 OEMODULAToRs 235 GROUP m GROUPnI CHANNEL j; l sEPARAToR sEPARA-IOR a En 275*DEIAOIzIULA-roRs E 277 TO OTHER GROUP SEPARATORS Y TO TRANSMITTER TO OTHER DELAY DEVICES AND MULTI-PLEXING CIRCUITS FIG. II
INVENTOR. DONALD D, GRI EG BY /57 i April 26, 1949. D. D. GRIEG PULSE TIME MODULATED MULTIPLEX SYSTEM 7 Sheets-Sheet '7 Filed Oct. 50, 1945 FROM RECEIVER CHAN FROM BLOCKING CIRCUIT FROM HIGH Q' CIRCUIT a PI-IAsER-.
FROM MU LTI-VIBRATOR GROUP I FROM M|XERCL|PPER DELAYED BLOCKING WAVE.
GROUP II'.
FROM MIXER-CLIPPER.
TIME
m m n LY N f. 6 a n m L E m T E V A .m W n m m m w 5 B S U A D N W PN E PN P D E UN M UN U .E S OA L OA O X A RH E RH R I B GC D GC G M FIG. I2
f@ lA T TORN E Y Patented Apr. 26, 1949 PULSE TIME MODULATED MULTIPLEX SYSTEM noualu D; Grieg,
Forest Hills, kN. Y., assigner to Federal Telephone andrRadio Corporation, New York,` N. Y., a corporation of Delaware pplication ctober 30, 194.5., Serial No. 625,649
This inventidfl relates to a; multichannel cm- Inurllc'atn SYStem fO'f t'reinslrittln'g'Y and receiving a signal inodl'ilatedA cdnplexpulse Wave. More particularly, it deals"` with the' I'n'ethodV and means for multiplexing trains' of complex pulses'to form a complex' pulsevave in which both a' leading edge andv a trailing edge o'f each complex pulse is tlle rrofleltd ao'cdlllg t0 different signals.
lt isV an object of this invention to produce a complex signal modulated puls and to multiplex such pulses on a ciiplexpulse WaveV in an lecuve manner'. Y,
Another'olijet is trv'sl't lld receive Such a multiplexed complex oul'sejwave;
Another object is tournul'tiple'x trains of such complex pulses( vrtic" lly'v by stacking tvvo' or'more trains of tl'leno'n' tpff each' tl'le to produce single train of step'shapd pulses".
Allotlle" Object is t 50th' vertically" and' holzontally multiplex o'f such complex pulses to produce a Single train of step'sha'ped' complex pulses.
Anothf olo'jeo't is'to separate and demodulate such r'nl'lltilvle'xed pulse va'ves'.
Another object" is to time modulate different signals on the edgesof eacl'l coipl'ex'y pulse.
Another' object is topovide the' means for carrying out the objects" mentioned alive.
Still other objects" ldlf'ealtllltesl of this invention WillA appear" fln tln'et' tine in the descrip?- tiOn" WhchvllOWS':
Generally sleakilg]-y this invention" crnpises the steps df (1)' pls()(llicir'gV a. c'ollplex pulse wherein its lelicllrlijg dg-eis modulated according t one signal' and its trailingV edge is modulated according t0 a d'iffet signal," as desoriloed in iiiy co`peidilg`v` appltir'lf, Sei. No. 614,079,1le'd Septnbef'l, 1911-5', and of (2) vertically', lo'ifzv'ntally or veftcally' and l'i'nfi'zillfallfyAr` multiplexing such complex pulses to f'rri a complex pulse Wave. y
The SOllllcs 0f Sig'l'gy which zle rndllated onl tl'e coin'plex pulses" may he vfrom code signals, audio signals, vidosig'nals, Orth-e like.
The means fofproduoiiig the trains of complex pulses modulated according tothe energy from said signal sourdes" inclu es a base Wave source, such as a sine' Wave, savftootl Wave, pulse Wave, or the like, having a constant frequency and at Claims. (Cl. 179-15) least one sloping edge on each pulse or undulation of the Wave. This base Wave then may be clipped along the sloping edge', its undulations at different levels varying in accordance with the energy in a given signal. The resulting train of pulses clipped from' the base vvavel thus are time modulated in accordance with the energy of said signal. Other trains of pulses, out-of-ph'ase with at least one time' modulated edge of any other pulse train, may beproduc'ed by clipping the base Wave at other levels and/or by' delaying the base Wave so' that a delayed base Wave is produced which is out-of-phase with the original base Wave and clipping the resulting delayed hase Wave at the original or' at other levels in accordance with the energy Afrom' another signal. Two pulse trains having time' modulated edges out-of-phase with each other, may be combined to` form a nev'v and complex pulse train in which the leading edge of each pulse thereof is time modulated according to one" signal and the trailing edge of each pulse thereof is time modulated according to another signal channel.
Tvvo or more trains of these new complex pulses are then multiplexed to form a single con'plex pulse Wave'. The multiplexing of trainsy of' these complex pulses, may .be (l) by vertically stacking one or more pulsesv from diiierent pulse trains to produce a step shaped pulse (each one of the complex pulses having a dilierent Width to permit such stacking) or (2) by horizontally interleaving groups of two or more complex pulse trains the number lo'eing dependent upon the duration of the complex pulse; or (.3) byA both vertically and horizontally multiplexing trains of suchv :conplex pulses. In order to facilitate modulation-and separation of horizontal multiplexed pulse trains, a synchronizing' pulsemay be interleaved between the complex' pulses at regularv intervals, such as between each similar group of diiiererlt signal channels.
The resulting complex pulse vave, having complex pulses multiplexed thereon', may be transinitted and received loyl any suitable high frequency means such as by radio, by Wires or the like. The received multiplexed complex pulse Wave is then separated into pulse trains corresponding to each signal channel transmitted on the complex pulse Wave. The thus separated pulse trairiskare separately time demo'dulated. Horizontally multiplexed pulses may be separated by providing a blocking Wave to" select only those complex pulses from a given' train' or `grou'p'of signal channels'. Thefwthus" sep'arratedv complex pulse train is then further separated into pulse`A trains corresponding to each signal channel thereon, either by clipping means (if the complex pulse is also vertically multiplexed) and/or by differentiating means to separate the leading edges from the trailing edges of each complex pulse. If desired, when the complex pulse wave contains both horizontally and vertically multiplexed pulse trains, the vertically multiplexed, or step shaped pulses, may rst be separated by clipping means before being horizontally separated by a suitable blocking wave.
These and other features and objects of the invention will become more apparent upon consideration of the following detailed description of several embodiments of the invention to be read in connection with the accompanying drawings in which:
Fig. l is a schematic wiring diagram partially in block of one embodiment for producing a vertically multiplexed complex wave of this invention;
Fig. 2 is a graph of the wave forms useful in describing the operation of the system of Fig. 1;
Fig. 3 is a schematic wiring diagram of another system for producing a vertically multiplexed complex wave similar to that produced by the system of Fig. 1;
Fig. 4 is a graph of the wave forms useful in describing the operation of the system of Fig. 3;
Fig. 5 is a schematic wiring diagram mostly in block of a system for separating and demodulating a vertically multiplexed wave produced according to the system of Fig. 1 or 3;
Fig. 6 is a graph of the wave forms useful in describing the operation of the system of Fig. 5;
Fig. 7 is a schematic block wiring diagram of a system for producing a horizontally multiplexed complex pulse wave;
Fig. 8 is a graph of the wave forms useful in describing the operation of the system of Fig. 7;
Fig. 9 is a schematic wiring diagram partially in block of a system for separating and demodulating the complex pulse wave produced in the system of Fig. 7;
Fig. 10 is a graph of the wave forms useful in describing the operation of the system of Fig. 9;
Fig. 11 is a schematic block wiring diagram of a system for producing a vertically and horizontally multiplexed complex pulse wave;
Fig. 12 is a graph of the wave forms useful in describing the operation of the system of Fig. 11;
Fig. 13 is a schematic wiring diagram partially in block of a system for separating and demodulating the complex wave produced in the system of Fig. 11; and
Fig. 14 is a graph of wave forms useful in describing the operation of the system of Fig. 13.
IIhe following description is divided into three chapters: Chapter I, illustrated in Figs. 1-6, discloses a vertical multiplexing system; Chapter II, illustrated in Figs. 7-10, discloses a horizontal multiplexing system; and Chapter III, illustrated in Figs. 11-14, discloses a vertical and horizontal multiplexing system.
CHAPTER I Vertical multiplexing system Referring to Figs. 1 and 2, there is shown a base Wave generator I for producing a base wave such as the sine wave 2, which is connected through lines 3 to a modulator clipper 4 which clips a segment 5 out of a sine wave 2 between limits 6 in accordance with the energy in the signal a introduced through the line I into the modulator clipper 4. The clipped segment producing the pulse train 8 is then passed through line 9 to the differentiator clipper I8 and thence to the mixer II. The details of the modulator clipper 4 and differentiator clipper IEB are shown in connection with the circuit for modulating sig- 'nal b below. Since the base wave 2 is clipped along its sloping edge at different levels corresponding to the energy in signal a, the edges of the pulses I2 on pulse train 8 vary toward and away from each other in accordance with the signal energy a, i. e., the edges of the pulses I2 are time modulated according to the energy in signal a.
Since the pulses multiplexed in the system of this invention are complex, i. e., having a different signal modulated on the leading edge from that of the trailing edge, only one edge of the pulse I2 is needed in producing the complex pulse. Therefore, the leading edge of pulse I2 is separated from the trailing edge thereof, by differentiating the pulse train 8 to produce the differentiated pulse train I3 wherein only the leading edges of the pulses I2 appear as positive pulses Ill. These pulses Ill are removed from the rest of the train I3 by clipping it along the line I5. To prevent overlapping of the pulses of one signal with those of another, the clipping level limits 6 of the different signals may be varied within, different voltage ranges along the sloping edge of the wave, as shown and described later in Fig. 4 or the phase of the base wave may be changed and the clipping may take pulses at the same levels 6 as shown in Fig. 2.
For producing the edge pulse time modulated in accordance with the signal b, the base wave from the generator I is passed through line I6 to the delay mechanism, such as the phase shifter I'I comprising a condenser 8 or a variable resistor I9, to produce the delayed base wave 26 shown in dotted lines in Fig. 2. Although the wave 2t is shown delayed an amount so that the leading edge of a pulse train clipped therefrom is in synchronism with the trailing edge of the p ulse train of the original base wave no overlap occurs because only the leading edges of each clipped pulse train are used. Such a delay, however, is not necessary lprovided there is no overlap between the time modulated signal channels of the different signals a. and b. The delayed base wave 2S then passes through line 2| into the modulator clipper 22 which may comprise a double diode 23 and an audio frequency transformer 2li. The signal b is then connected to transformer 24 through line 25 and its energy varies the level of the clipping segment 5 between the limits 6. The width of the segment 5 is determined by the adjustment of the variable resistors 26 and 2l. From the plate 28 of the tube 23 is withdrawn the clipped pulse train 29 having pulses 28u. with leading and trailing edges time modulated in accordance with the signal b. This pulse train 29 then passes through line 30 to a diiferentiator clipper 3l, which may comprise a diiferentiator circuit consisting of condenser 32 and resistor 33, for producing the differentiated pulse train 34. Diiferentiated pulse train 34 isthen passed on to one of the grids of the clipper tube 35 which is biased through the resistor 33 so as to pass only the positive pulses 36 of the differentiated pulse trains S4 by clipping them olf along the line 3l. These Ipositive pulses 36 are then withdrawn from the plate of tube 35 through the line 38 into the mixer II.
The mixer may comprise two triodes 39,:the grids of which are coupled-in parallel with :the lines from the differentiator clippers l and 3|. These triodes 39 prevent venergy in the pulses of one differentiator clipper circuit Vfrom feedingA back into the circuit of the other diiferentiator clipper. From the plates of the triodes 39 .is withdrawn a combined complex pulse train 40 through line 4|. The odd numbered pulses .on this train 40 corresponding to the time modulated .signal channel d and the even numbered vpulses correspond to time modulated signal channel b. In order to combine these two pulsesv into a. single wider complex pulse, the train .40 `is passed to a trigger circuit 42 from which is withdrawn the complex pulse train 43 through line 44. The trigger circuit 42 may comprise .a pair of triodes `45 .coupled in such a manner that an'odd numbered pulse causes one of the tubes to nre aneven numbered pulse fires the other tube'which then remains conductive until the next odd numbered pulse lires the first tube again, and so on. Thus, this circuit produces the complex wave 43, which then is. passed through line 441 to the mixer45.
Signals c and d may be similarlymodulated on further delayed base waves 41 and 48 respectively, produced from the base wave 2 in phase Shifters 49 and 50 connected to generator |v through'line I6. These delayed waves ,41 and 48 are modulated and clipped in circuits and 5,2 (similar to circuit 22) from the energy of signals c and d introduced through linesr 53. and 5'4, respectively. From the modulator clippers 5t and 52A are `withdrawn pulse trains 55 and 56 which are separately differentiated and.v clipped in circuits 51 and'. 58 (similar to. differentiatorf clipper circuit 3|) to produce trains of positive pulses l5.9 and 60, respectively. These pulses 59 and 60 are mixed in a mixer 0| to produce the pulse train 62 which is. passed to a trigger circuit 83 (similar to 42) -to produce the complex .pulse train 64 which passes to the mixer 45, (similar tothe mixer It). From the mixer 46 isvwithdrawn` a vertically multiplexed complex step shaped pulse wave 65 through line 65 for transmission by a suitable ultra frequency apparatus. In order to vertically stack the complex pulses produced on wave trains 43 andl 64, it is` necessary thaty the basic width of the pulses in each train be different. However, if the pulses had the same width and were sufficiently out-oif-phase with each other to partially overlap a complex step pulse could be formed wherein theleading edge of one pulse train would be on the leading edge of the first step of the step shaped pulse, and thev trailing edge of that pulse on the same pulse' train would be. on the trailingedge of the second step of the step shaped pulse, and correspondingly the leading edge of each pulse of the second pulse` train would be the leading edge on the second' step of the step shaped pulse and the trailing edge of that pulseon the same second pulse train would be the trailing edge of; the rst step ofj the step shapedpulse. Complex step shaped pulses of this type may be employed4 in scrambling signal channels for secrecy.
Another system for producing trains of complex. pulses and vertically modulating them on a, com plexwave similar to wave 8,5.isl disclosed inl Figs.. 3 and 4,.wherein61. is. a pulse generatpr producing; 31 91.115@A Wave. 63 -WhCh StIaIlSmtiled; 13112011.5511 lille. 69 t0 leading. edge andl trailing edsewave. Shapers, 1'0 and 1| respectively., v'lhese Shapers` produce waves having sloping, .edgeswhich may be media:-`
differentiated. pulsetrain from pulse lator iclipped to form pulse trains Ahaving rtimed modulated pulses.
`Leading edge wave shaper 10 produces from the base pulse wave 68 inverted wave 12 having pulses or undulations with a leading sloping edge 13 through themeans of a tube 14 and condenser 15. .The shaped base wave 12 is then connected through line 18 to a network of modulator clippers 11, 18 and 19 (similar to modulator clipper 22 shown in Fig. 1) wherein the wave 12 is modulator clipped Vat the different channel levels shown in Fig. 4 to produce pulse trains having time modulated leading edges only (since trailing edge 8| is vertical) corresponding to the energy in signals a,-b and c, respectively. The resulting pulse trains (not shown) are separately passed to the mixer 89 (similar to'mixer shown in Fig. 1).
The .trailing edge wave shaper 1| comprises a delay device 83, a phase inverter 84, and a differentiator clipper .85. The delay device 83 may comprise a network of inductances and condensers to yassimilate the transmission line. The phase inverter 84 may comprise a triode 80, from the plate of which is withdrawn the delayed and inverted pulse wave 81 through line 88. This wave 81 is thenpassed to the diilerentiator. clipper 85 (similar to 3| shown in Fig..1 without transformer 24) contains circuit elements of suiiicient magnitude to produce a wave of the form 89. Wave 89 is then clipped along the line 90 in the tube 85a, to produce a second shaped base wave of positive undulations having vertical leading edges 9|, in exact alignment and synchronism with the trailing'edge 8| of wave 12, and having a sloping trailing edge 92 complementary to the edge 13 of wave 12. Since the tube 85a inverts the wave 89, a phase inverter 84a similar to 84 is required to produce the positive undulations of wave 89. These positive undulations are then passed through line 93 to the modulator clippers 94, 95 and 96 and clipped at the different channel levels shown in Fig. 4 to produce pulse trains (not shown) corresponding, respectively, to signals d, e and f introduced into these modulator clippers, (also similar to the modulator clipper 22). The separate pulse trains are then passed into the mixer 80 from which is withdrawn, through line 91 for transmission, a vertically multiplexed complex step shaped pulse wave 98 similar to the wave 65.
In Figs. 5 and 6 is shown a system for separating and demodulating a vertically multiplexed complex step shaped pulse wave of the type produced in the system of Fig. 1 or 3. Such a complex wave is shown again in Fig. 6 at 99, which is received over line |00 in Fig. 5 and coupled to the separate channel clippers |0|`, |02, and |03.
The channel clippers |0|, |02 and |03 may be similar to the double clipper circuit 22 shown in Fig. 1 without the transformer 24 therein. A schematic Wiring diagram of such a double clipper is disclosed later in Fig. 13. These channel clippers clip off the different steps of the complex pulses on wave 99 as shown between the horizontal lines in Fig. 6. Since both the leading edge and the trailing edge of each step carries a difierent signal channel, each clipped step comprises a complex pulse train (such as train |04 for signal channels a and b) wherein each pulse carries two signal channels. r'Ihe complex pulsetrains from the clippers |0|, |02 and |03 are then respectively passed to the diiierentiators |05, |08, and |01 to separate the leading from the trailing edges of each pulse on the pulse trains. For example, the train |104 is shown at |08. The diierentiated pulsetrains are then slipped to remove the positive pulses corresponding to signal channel a, c and e in clippers |09, I and respectively. To separate the edge pulses of channels b, d and f, respectively, the diiierentiated trains from |05, |06 and |01, are passed through the phase inverters ||2, ||3 and H4' to produce an inverted train (similar. to |5 which corresponds to channel b) which trains are then clipped in clippers ||6, Ill, ||8. (The clipped time modulated pulse channels for signals a and b are shown by Waves ||9 and |20 respectively.) The separated pulse train channels are then each separately demodulated in the pulse time demodulators |2|, |22, |23, |24, |25 and |26 from which are withdrawn reproduced signals a, b, c, d, e, and f, respectively. The pulse time demodulators may include a harmonic generator |21 which produces a wave having sloping edges and preferably is a harmonie of the original base wave y6| produced in the system of Fig. 1 or 3. The addition of a pulse -channel train to the sloping edges of such a harmonic wave, produces amplitude modulated pulses on the. wave, which may be clipped off in tube |28 and passed through the low pass filter |29 from which is withdrawn the desired signal, which in this :case is a. More details of such a time demodulator are disclosed in my copending application Serial No. 459,959, led September 28, 1942, U. S. Patent No. 2,416,306, granted Feb. 25, 1947.
CHAPTER II Horizontal multiplexing system In Figs. 7 and 8 is shown a system for horizontally multiplexing a series of complex pulses in which each pulse has one signal modulated on its leading edge and another signal modulated on its trailing edge. This system comprises a base wave generator |30 for producing the wave |3| which passes through line |32 into a double clipper |33 (similar to that shown in Fig. 13 described later) which cuts the top oil of the undulations of wave |3|, to produce a train of synchronizing pulses |34 that are passed through line |35 to the mixer |36.
The signals to be transmitted are modulated from different delayed base waves out-of-phase with the wave |3|. These different delayed base Waves are produced from the series of delay devices |31, |38, |39, |40, |4|,`|4'2 and are shown in dotted lines in Fig. 8 at |43, |44, |45, |46, |41 and |48, respectively. The base waves are then modulator clipped, respectively according to signals a, b, c, d, e and f in modulator clippers |49, |50, I5 |52, |53, |54, to produce a series of pulse trains similar to those for signal channels a, and b shown in Fig. 8 as trains |55 and |56. Since the next complex pulse train is composed of pulses corresponding only to the leading edges of the pulses on trains |55 and |56 these trains are diierentiated to form trains |55a and |56a and then clip- Vvped to remove only their positive pulses in the" 'rst two of the diferentiator clippers |51, |58,
|59, |60, |6|, |62, respectively. The resulting positive pulse trains from the clippers |51 and |58 are then mixed in mixer |63 (similar to mixer in Fig. 1) from which is withdrawn the pulse train |64 which is then passed into trigger circuit |65 (similar to trigger circuit |42 in Fig. 11) to produce the complex pulse train |66 which is passed to the mixer |36. Likewise the pulse trains of signal channels c and d are mixed in mixer |61, triggered in circuit |68, and passed to mixer |36, and similarly pulse trains of signal channels e and f are mixed in mixer |69, triggered in circuit |10, and passed to mixer |36. From mixer |36 through line 1| is Withdrawn the horizontal multiplexed complex pulse wave |12, having synchronizing pulses S interleaved between each similar group of different complex pulse channels. If desired, further signal channels, besides the six shown, may be produced and interleaved between the synchronizing pulses S. Such additional circuits Would be connected to other delay devices through line |14 and to the mixer |36 through line |15.
Figs. 9 and 10 disclose a system for separating and demodulatingthe signals on a horizontally multiplexed complex pulse Wave of the type of |12. Such a Wave is received through line |16 and connected to the pulse width selector 11 and the complex pulse train selectors |18, |19, |80.
The pulse width selector 11 (similar to that disclosed in my copending joint application Ser. No. 487,072, led May 15, 1943, U. S. Patent No. 2,440,278, granted April 27, 1948) separates the synchronizing pulses S on Wave |12 from the wider time modulated complex pulses carrying the signal channels. This pulse width selector may comprise an amplifying tube |8| for amplifying the current of the pulse Wave |12, which is then passedinto the time constant circuit |82 tuned to be responsive to the width of the synchronizing pulses S. The undulations of the time constant circuit |82 are damped through damping tube |83 so that only the rst undulations having the greatest amplitudes are clipped in clipper circuit of tube |84' to produce the synchronizing wave |85. From this wave |85 is then produced a blocking wave |88 in the multivibrator |81. The circuit of the multivibrator |81 may comprise two tubes |88 and two time constant circuits, comprising: (1) variable resistor |89 and condenser |90 and (2) variable resistor |9| and condenser |92. These latter time constant circuits are adjusted so that the pulses on Wave |85 lires one of the tubes |88 which remains conductive for a time suicient to completely block any one of the signal modulated pulses on wave |12, and then the other tube |88 is red and remains conductive until the next pulse on wave |85 res the rst tube again. This block Wave |86 is then withdrawn through line |93 and connected to the series of delay mechanisms |94, |95 and |96, for delaying the wave 86 so it will bein synchronism with each dilerent train of complex pulses on wave |12.
The resulting delayed blocking Waves withdrawn from the delay devices are then respectively coupled to pulse trainselectors |18, |19 and |80, each of which may comprise a mixer clipper circuit. The mixer clipper circuit may comprise two triodes |91, the grids of which are connected respectively to the delayed blocking wave and to the complex pulse wave. Each one of these tubes are biased suiciently so that the composite wave |98 will be clipped. along the line |99 to remove only the desired train of signal pulses.
This selected complex pulse train is then withdrawn through line 200 and passed through the diierentiator 20| to produce the differentiated pulse train 202 which differentiated pulse train is both (a) clipped along line 203 and (b) inverted (to produce wave 204) and clipped along line 205, to separate signal channels a and b respectively carried on the leading and trailing edges of each pulse of the selected complex pulse train. The resulting separated signal channels are pulse time demodulatedto reproduce the signals a and b withdrawn through lines 206 and 201, respectively. This circuit 208 from pulse train selector |18 is the same as that disclosed for the separation and demodulation of the complex pulses described in Fig. above and will be referred to hereinafter as a channel separator and demodulator circuit.
The other complex pulse separated in the pulse selectors |19, |80 and the channels thereon are separated and demodulated in the channel separator and demodulator circuits 209, 2|9v (similar to circuit 205) from which are withdrawn Signals c, d, e, and f through lines 2| I, 2 I2, 2I3, 2 I4, respectively. Other pulse trains may be selected in a similar manner and connected to lines 2 I 5, and 2|6 carrying the received complex pulse wave and theblocking wave, respectively.
trains are similarly CHAPTER III Vertical and horizontal multiplexing The vertically multiplexed step Ishaped complex pulses produced by the systems disclosed in Chapter I may also be horizontally multiplexed according to the system In Figs. 11 and 12 there is shown such a system comprising a base wave generator 2|1 for generating the Wave 2|8 which is connected through line 2|9 to the group'I vertical multiplexing circuits 223 for producing a vertically multiplexed pulse wave 22| containing signal channels a, b, c, d, etc., which is withdrawn through the line 222 and to a mixer 223 (similar to I I in Fig. 1). The vertical multiplexing circuits may be similar to those disclosed in Fig. 1 or Fig. 3 above. The wave 2|8 is also passed through line 224 to a suitable delay device 225 from which is withdrawn the delayed base wave 226, which is then connected to group II vertical multiplexing circuits 221 from which is withdrawn a vertically multiplexed pulse wave 228 which is passed through line 229 of the mixer 223. Still other delay devices and vertical multiplexing circuits may be connected to line 230 to produce other then connected to the mixer 223. From mixer 223 is withdrawn the resulting vertically and horizontally multiplexed complex pulse wave 23|, through line 232 for transmission.
In Figs. 13 and 14 is shown a system for separating the channels on a `complex pulse wave oi' the type `shown at 23|. Such a wave is passed through line 232 and connected both to a blocking wave circuit 233 and to groups I, II and III, etc., separator circuits 234, 235, 236, etc. This system does not disclose the use of a synchronizing pulse for separating similar groups of complex pulses as described in the system of Chapter II, but instead discloses a circuit whereby a blocking wave may be produced directly from the complex pulses on the wave 23 I.
The blocking Wave circuit 233 'consists of a high-Qcircuit 231, a variable sine wave phaser 238, a double clipper 239, a differentiator 240, and a multivibrator circuit 24|. The high-Q- circuit 231 may comprise a tube 242 and a time constant circuit 243 for smoothing out the sharp corners on the wave 23| and produce a sine wave which is Withdrawn-through line 244 into the variable sine wave phaser 238 consisting of a condenser 245 and a variable resistor 246. The variable sine wave phaser is so adjusted that the leading edge of each positive undulation on the Waves 241 and 250are in synchronism with 4the group pulse waves which arek disclosed in Chapter II.
center of the spaces 255 between the complex pulses on the Wave 23|. From the'sine'vvave phaser 238 is withdrawn the delayed sine wave 241 through line 248 into the double clipper circuit 239, similar to clipper modulator circuit 22 shown in Fig. 1 but without the transformer 24. In circuit- 239, the double diode 249 also may act as an amplifier as Well as a clipper for clipping off the round ends of the wave 241 and thereby produce the rectangular shaped Wave 250 which is withdrawn from theplate 25| of tube 249 through line 252. The resistors 253 and 254 may be adjusted and biased to aid in shaping the square wave 256. rIhe wave 250 is then passed to the difierentiator circuit 240 from which is withdrawn the pulse wave 256. This pulse wave is then passed into the multivibrator circuit 24| to produce the blocking wave 251. This multivibrator circuit is similar to the multivibrator circuit |81 shown in Fig. 9, the resistors 253 and 259 in the time constant circuits thereof being so adjusted as to provide pulses 266 on wave 251 of sufiicient duration to reach from one space 255 to the next adjacent space 255 of the same frequency as a given group complex vertically multiplexed pulse train interleaved on the wave 23|. The blocking wave 251 is then passed through line 26| into a group I separator circuit 234 which in this case comprises a mixer clipper similar to that disclosed at |18 in Fig. 9. In the mixer clipper the wave 262 is produced and clipped along the line 263 to separate the cornplex vertically multiplexed pulses 264 of group I. These pulses 264 are then passed through line 265 to the group I channel separator and demodulator circuits 266 similar to those previously described and from which are withdrawn the reproducedr signals a, b, c, d, etc.
The group II separator circuits 235 comprises, in addition-to a mixer clipper 261, a delay device 268 for delaying the blocking wave 261 to produce the delayed blocking wave 269. This delayed wave 269 is mixed in the mixer clipper v251 to produce the Wave 210 which is clipped along the line` 21|. The resulting clipped pulses 212 are then passed through line 213 to the group II channel separator and demodulator circuits 214 which may be similar to those of 256 and from which are withdrawn the reproduced signals e, f, c, h. etc.
Group III separator 236 is similar to the group II separator 235 and the group III channel separator and demodulator circuits 215 are similar to those of group I at 266 lor group II at 214. Still further, group separator and demodulator circuits may be connected to the lines 216 and 211, if desired.
The foregoing systems may be extended to multiplex channels other than those specifically shown, provided a sulcient free .space is maintainedV between each of the signal channels to avoid cross talk from one signal channel to the other. This applies both to the vertical multiplexing and to horizontal multiplexing of vthe time modulated edges of the complex pulsesA produced by the systems of this invention and my copending application, Serial No. 614,019, led September` 1, 1945.
While the principles of the invention have been described inconnection with several specific systems it is to be clearly understood that these descriptions are made only by way of example and not asa limitation on the scope of the invention as defined in the objects and the -accompanying claims.
I claim:
1. In a multichannel system means to produce a pulse having vertically disposed portions yof different Widths and means to time modulate the leading edge with one signal and the trailing edge with another signal of each such portions.
2. A system for multiplexing signal modulated pulses to produce a complex pulse wave wherein each pulse carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: at least two sources of signal energy, means to produce a plurality of pulse trains respectively time modulated with energy from said signal sources, said pulses being out-of-phase `with each other, means to combine two pulses from diierent pulse trains to form a single new pulse train, and means to multiplex a plurality of said new pulse trains to produce said complex pulse wave.
3. The system of claim 2 wherein the means for multiplexing includes means to superimpose the pulses of said new pulse trains to produce a step shaped pulse on said complex pulse wave.
4. The system of claim 2 wherein the means for multiplexing includes means to interleave the pulses of said new pulse trains on said complex pulse wave.
5. The system of claim 2 wherein the means for multiplexing includes means to superimpose the pulses of said new pulse trains to produce step shaped pulses and means to interleave said step shaped pulses on said complex pulse wave.
6. The system of claim 2 wherein said means for producing a plurality of pulse trains includes means to produce a base wave having a sloping edge, and means to clip said base wave along said sloping edge at various levels corresponding to the energy from said signal sources.
7. 'Ihe system of claim 2 wherein the means for producing a plurality of pulse trains includes a base wave source, and means to produce two similar waves, out-of-phase with each other, from said base wave.
8. A system for multiplexing signal modulated pulses to produce a complex pulse wave wherein each pulse carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: at least two sources of signal energy, a base wave source, means to change the phase of said base wave, means to produce pulse trains from the original base wave and the base waves out-of-phase with the original base wave, means for respectively modulating the pulses of said trains with energy from said signal sources, means to interleave the pulses of said pulse trains to produce a new pulse wave means to combine successive pairs of pulses on said new pulse wave to form a series of single pulses each bearing two modulated signal channels, and means to multiplex a plurality of the resulting new pulse waves to produce said complex pulse wave.
9. The system of claim 8 wherein said means to combine successive series of pulses comprises a trigger circuit means.
10. The system of claim 8 wherein said means to produce one of said pulse trains includes a diierentiating means and a clipping means.
11. A system for multiplexing'signal modulated pulses to produce a complex pulse wave wherein each pulse carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: at least two sources of signal energy,
means to produce a plurality of pulse trains respectively time modulated at one edge per pulse with energy from said signal sources, means controlling said pulse trains so that the unmodulated edges of corresponding pulses of said pulse trains coincide, means to combine corresponding pulses from each train into a single pulse on a new pulse train, and means to multiplex a plurality of said new pulse trains to produce said complex pulse wave.
12. The system of claim 11 wherein said means to produce a plurality of pulse trains includes a base wave source, means for separating said base wave to produce two base pulse waves one of which has pulses with a sloping leading edge and the other of which has pulses with a sloping trailing edge, said base pulse waves being outof-phase with each other.
13. A communication system for transmitting and receiving a complex pulse wave having more than two signal channels modulated thereon comprising: more than two sources of signal energy, means to produce a plurality of pulse trains respectively time modulated with energy from said signal sources, said pulses being out-ofphase with each other, means to interleave the pulses of said pulse trains to produce a, new pulse wave, means to combine successive pairs of pulses in said new pulse waves to form a series of single pulses each bearing two signals, means to multiplex a plurality of the resulting combining pulse waves to produce a complex pulse wave wherein each pulse carries at least one time modulated signal in a leading edge thereof and another time modulated signal on the trailing edge thereof, means to transmit said complex pulse wave, means to receive the complex pulse wave, means to separate said complex pulse wave into pulse trains corresponding to each of said signals modulated thereon, and means for demodulating each of said pulse trains.
14. The system of claim 13 wherein said means for multiplexing includes means to superimpose the pulses of said new pulse trains to produce a step shaped pulse on said complex pulse wave.
15. The system of claim 13 wherein the means for multiplexing includes means to interleave the pulses of said new pulse train on said complex pulse wave.
16. The system of claim 13, wherein said means for multiplexing includes means to superimpose the pulses of said new pulse trains to produce step shaped pulses and means to interleave said step shaped pulses on said complex pulse wave.
17. A communicating system for transmitting and receiving a complex pulse wave having horizontally multiplexed pulses thereon wherein each of said pulses carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof, comprising: more than two sources of signal energy, a base wave source, means controlled by said base wave to produce a synchronizing pulse, means controlled by said base wave to produce a plurality of pulse trains respectively time modulated with energy from said signals, all the edges of said pulses produced from said base wave being out-of-phase with each other, means to combine two pulses from `dilerent pulse trains to form a single new pulse train, means to horizontally multiplex a plurality of said new pulse trains to produce a complex pulse wave having a synchronizing pulse interleaved at regular intervals between the complex pulses thereon,
means to transmit said complex pulse wave, means to receive said complex pulse wave, means to separate the signals modulated on said complex pulse Wave comprising a blocking wave controlled by the synchronizing pulse on said complex pulse wave, means for separating the signal channels on the separated pulses to produce pulse trains corresponding to each signal carried by said complex pulse wave, and separate means to demodulate each of said separated pulse trains.
18. A method of communicating a complex pulse Wave carrying a plurality of multiplexed time modulated signals, wherein each pulse on said wave carries one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof comprising: producing a plurality of pulse trains respectively time modulated with energy from said signals, said pulses being out-of-phase with each other, combining two pulses from different pulse trains to form a single new pulse train, multiplexing a plurality of said new pulse trains to produce said complex pulse wave, transmitting said complex pulse wave, receiving said complex pulse wave separating the signals on said received complex pulse wave into separate pulse trains corresponding to each of said signals, and separately demodulating said separated pulse trains to reproduce said signals.
19. In a communication system for receiving a complex pulse wave having multiplexed complex pulses thereon, said complex pulses having one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof, said complex pulses being horizontally multiplexed in an interleaved manner, means for separating the wave into pulse trains corresponding to each signal modulated on said complex wave, said separating means including means for producing a blocking Wave having the same frequency as a given train of complex pulses to separate a given pair of signal channels, and means for separating said separated pairs of signals comprising diierentiating means, and means for demodulating each of said separated pairs of signals.
20. In a communication system for receiving a complex pulse Wave having multiplexed complex pulses thereon, said complex pulses having one time modulated signal on a leading edge thereof and another time modulated signal on the trailing edge thereof, said complex pulses being both vertically and horizontally multiplexed on said complex pulse wave, means for separating the wave into pulse trains corresponding to each signal modulated on said complex Wave, said separating means including a blocking wave for separating the horizontally multiplexed complex pulses, a clipping means for separating the vertically multiplexed pulses, and a diierentiating means for separating the leading edge from the trailing edge of the pulses of the resulting separated pulse train to thereby separate the signal channels, and means for demodulating each of said separated edges to reproduce the signal.
DONALD D. GRIEG.
REFERENCES CITED The following references are of record in the file oi this patent:
UNITED STATES PATENTS Number Name Date 2,266,194 Guanella Dec. 16, 1941 2,406,790 Beatty et al Sept. 3, 1945 2.419.292 Shepard Apr. 22, 1947
US625649A 1945-10-30 1945-10-30 Pulse time modulated multiplex system Expired - Lifetime US2468059A (en)

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US2543738A (en) * 1947-11-15 1951-02-27 Rca Corp Time division pulse multiplex system
US2552496A (en) * 1942-11-30 1951-05-08 Rinia Herre Receiver for modulated radiofrequency pulses
US2566832A (en) * 1946-12-18 1951-09-04 Rca Corp Synchronizing circuit
US2578939A (en) * 1948-03-01 1951-12-18 Moran Instr Corp Telemetering
US2655652A (en) * 1948-06-28 1953-10-13 John H Homrighous Multiplex time division telephone systems
US2697783A (en) * 1946-02-13 1954-12-21 Robert C Miedke Signal generator
US2719187A (en) * 1949-08-17 1955-09-27 Bell Telephone Labor Inc High frequency pulse transmission
US2721938A (en) * 1950-01-27 1955-10-25 Gen Dynamics Corp Pulse generating means
US2773937A (en) * 1949-12-24 1956-12-11 Gen Dynamics Corp Electronic signaling and switching system
US2794071A (en) * 1951-10-20 1957-05-28 Itt Power line fault locator
US2860185A (en) * 1951-01-10 1958-11-11 Int Standard Electric Corp Keyed frequency modulation carrier wave systems
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US2989580A (en) * 1952-09-09 1961-06-20 Rca Corp Television systems
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* Cited by examiner, † Cited by third party
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US2552496A (en) * 1942-11-30 1951-05-08 Rinia Herre Receiver for modulated radiofrequency pulses
US2697783A (en) * 1946-02-13 1954-12-21 Robert C Miedke Signal generator
US2543736A (en) * 1946-06-28 1951-02-27 Rca Corp Pulse multiplex system employing step-wave commutation
US2566832A (en) * 1946-12-18 1951-09-04 Rca Corp Synchronizing circuit
US2543737A (en) * 1947-03-28 1951-02-27 Rca Corp Multiplex system
US2543738A (en) * 1947-11-15 1951-02-27 Rca Corp Time division pulse multiplex system
US2578939A (en) * 1948-03-01 1951-12-18 Moran Instr Corp Telemetering
US2655652A (en) * 1948-06-28 1953-10-13 John H Homrighous Multiplex time division telephone systems
US2719187A (en) * 1949-08-17 1955-09-27 Bell Telephone Labor Inc High frequency pulse transmission
US2773937A (en) * 1949-12-24 1956-12-11 Gen Dynamics Corp Electronic signaling and switching system
US2721938A (en) * 1950-01-27 1955-10-25 Gen Dynamics Corp Pulse generating means
US2860185A (en) * 1951-01-10 1958-11-11 Int Standard Electric Corp Keyed frequency modulation carrier wave systems
US2794071A (en) * 1951-10-20 1957-05-28 Itt Power line fault locator
US2989580A (en) * 1952-09-09 1961-06-20 Rca Corp Television systems
US2883530A (en) * 1954-09-30 1959-04-21 Bendix Aviat Corp Amplitude band selection circuit
US3175160A (en) * 1962-03-15 1965-03-23 Intron Int Inc Controlled current source
US3388214A (en) * 1965-02-03 1968-06-11 Zenith Radio Corp Compatible stereo sound system employing time modulation techniques

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