US2416286A - Signal transmission system - Google Patents

Signal transmission system Download PDF

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Publication number
US2416286A
US2416286A US461143A US46114342A US2416286A US 2416286 A US2416286 A US 2416286A US 461143 A US461143 A US 461143A US 46114342 A US46114342 A US 46114342A US 2416286 A US2416286 A US 2416286A
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US
United States
Prior art keywords
pulse
pulses
circuit
wave
tuned
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Expired - Lifetime
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US461143A
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English (en)
Inventor
Henri G Busignies
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STC PLC
Federal Telephone and Radio Corp
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Standard Telephone and Cables PLC
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Publication date
Priority to BE474051D priority Critical patent/BE474051A/xx
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to US461143A priority patent/US2416286A/en
Priority to GB17229/44A priority patent/GB593139A/en
Application granted granted Critical
Publication of US2416286A publication Critical patent/US2416286A/en
Priority to FR951032D priority patent/FR951032A/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K9/00—Demodulating pulses which have been modulated with a continuously-variable signal
    • H03K9/08—Demodulating pulses which have been modulated with a continuously-variable signal of duration- or width-mudulated pulses or of duty-cycle modulated pulses

Definitions

  • SIGNAL TRANSMISSION SYSTEM Filed' Oct. '7, 1942 2 sheets-sheet 2 v F 81+ J INVENTOR. HEN/Pl G; BUS/GN/ES ATTORNEY Patented Feb. 25, 1947 SIGNAL TRANSMISSION SYSTEM Henri G. Busignies, Forest Hills, N. Y., assignor to Federal Telephone and Radio Corporation, a
  • This invention relates to radio receiving systems and more particularly to time modulated impulse receivers.
  • the object outlined above and others are accomplished by providing means responsive to the received pulse formations for producing wave trains of a given frequency and an amplitude dependent upon the duration of the pulse formation and further means for terminating the wave trains prior to the reception of the succeeding pulse formation.
  • FIG. l is a block diagram of a receiver embodying the features of my invention
  • Fig. 2 is a set of curves used to explain the operation of the receiver in accordance with my invention
  • Fig. 3 is a circuit diagram of a tuned oscillating circuit which may be part of the circuit of Fig.1;
  • Fig. 4 is a modified tuned oscillating qcircuit system which may be part of the system of Fig. 1; and Fig. 5 is a set of curves used to explain further features of my invention.
  • a receiver element 10 for receiving and amplifying pulse modulation signals in the manner of the usual R. F. and I. F. stages.
  • Thesepulse modulation signals may be passed to demodulator and reshaper circuit H and from there passed to a tuned oscillation circuit l2 preferably a shock excited circuit which is provided with means such as the inherent damping of the circuit for terminating the produced wave prior to the reception of the succeeding group of pulses.
  • the waves produced in tuned circuit l2 are then detected in a detector amplifier circuit I3 and applied to headphones M.
  • an auxiliary amplitude modulation detector amplifier I5 may be provided with suitable translating apparatus l6.
  • the wave trains produced in the tuned oscillating circuit [2 are given amplitude characteristics dependent upon the spacing of the received pulse formations but substantially independent of the recurrence frequency of these pulse formations;
  • curve A represents pulse formations which are produced in a known manner in the output of demodulator reshaper II in response to pulse signals received at H].
  • These pulses may be substantially square wave formations as shown in curve A for the most efficient operation. It should be understood, however, that the system described is operative for other pulse formations as well.
  • Pulses 20 and 21 form one pulse formation and pulses 22 and 23 correspond to the succeeding pair of pulses'of the chain of received signal pulses have been reshaped, the recurrence period R of the pulse formations may be any desired amount. For example, this period R. may be varied from 39 to microseconds, this variation, of course, being controlled at the source of the signal pulses. Pulses 20 and 2
  • the intervalbetween the two pulses which as measured between leading edges thereof is indicated as P varies according to the intelligence with which the received signal pulses are modulated."
  • pulse 2'0 When pulse 2'0 is applied to the shock excited tuned 'cir'cuit, it immediately produces therein "a waveformation' shown"at- 30, curve B.
  • the circuit is tuned to one'megacycle frequency so that one alternate or half a wavelength of the-wave produced in the circuit will occur duringthe pulse width pe'ri'od D.
  • this pulse when applied. to .the same shock excited circuit tends to produc'e'an oscillation 180 out of phase with theoscillationproduced by pulse as shownvby the light line curve 3
  • This pulse accordingly serves to modify wave and substantially kills the oscils lation producing the resultant wave shown in the heavy line curve 3.2.
  • pulses 20 and 2-! move toward one another asshown by therdotte'd lines 44 and of curve A. Accordingly, the successive eifects ofpulses!!!) and 2
  • Curves B' and C may be considered as. representing the extreme modulation positions of pulses 20 and 2!.
  • the-successively received pulse formations serve to produce wave trains varying in amplitude in accordance with the duration of the'pulse formation interval independently ofthe recurrencefrequency R between thepulses.
  • the tuned oscillating circuit be controlled so that the wave formations produced thereindo not endure for a period greater than the time spacing" of these pulse formations.
  • the curves shown in Fig. 2 are all shown as being, highly damped to assure termination of the wave trains at a desired interval. In some cases, however, it may be preferable to use a tuned circuit which is nothighly damped and toprovide means for terminating oscillation of this circuit at a. desired period after the reception of pulses. By using the higher Q tuned circuit, greater amplitude of thereceived signals will be assured and the system therefore will be more sensitive to-the reception of signals.
  • FIG. 4 shows a paroscillations bythe succeeding received pulse formation. This action is indicated by the dotted 1 triangles 33; 33' shown in curves B and C respectively.
  • I providefurthera connection '56 from theinput of circuit i2'to the grid ?5 of tube l'i so that the received pulses will be applied to this tube causing it to be conductive and thoroughly damping any oscillations in tuned circuit BI, 62;
  • the delay line iii is-made of sufflcient length to permit passage of these pulses from the grid of tube 'il prior tothe application of the pulses 'to the tuned circuit over tube 68.
  • the pulses first are applied to the grid of tube H overtime constant circuit "l2, which includes condenser 71 and resistor '18, causing a damping of any oscillations in the circuit. Then these pulses are successively applied to the tuned circuit to produce the desired wave train. This wave train then persists for a period of time until the succeeding pulse formation reaches the receiver. These succeeding pulses are i l-- mediately applied to tube H damping out all signs of oscillation from circuit El, 62 after which this,
  • the length of the delay period may be controlled at will. It should, be also clear that instead of putting the delay line in the input circuit of the tuned circuit, the delay line could be placed in In this case, the period would be such as to terminate produced oscillations at a fixed time after arrival. ofthe pulses instead. of a fixed time prior to application of thezsucceeding pulses. This latter system, however, is generally less desirable sinceitrequires a much longer delay. period. for the pulse. I
  • the system as described above wherein the pulses are varied in spacing with respect to one another is preferred, but the principles of my invention apply also to other types of pulse modulation systems.
  • the type of pulse modulation system wherein one of the pulses is fixed in time and the other one is varied in accordance with the modulation is illustrated in curves J and K. of Fig. 5.
  • Curve J illustrate the fixed pulse 80 and variable pulse 8
  • this type of modulation is used.
  • pulse modulation comprises the product on of long pulses, the variation in len th of wh ch serves to indicate thetime modulation.
  • Such type of waves may also be used with a receiver embodying the principles of my shown at M.
  • the leading edge of pulse 90 tends to produce an oscillation in the shock excited circuit while the trailing edge of the pulse serves to modify the amplitude of this wave.
  • the pulse will produce a solid line curve 92 shown in curve M while in the dotted line position, the dotted curve 93 will be produced.
  • the leading edge When pulse is applied to the tuned oscillating circuit, the leading edge will tend to-prcduce oscillations therein.
  • the trailing edge will tend to produce oscillations in the opposite direction but since the trailing edge is much less steep than is the leading edge, the harmonic content thereof is much less so that this edge will serve'only to reduce the amplitude of the produced oscillations but will not cause extinction thereof.
  • the leading edge of pulses 25 will also serve to produce oscillations serving to modify those produced by the leading edge of pulse 25.
  • the harmonic frequency need not be limited to the odd harmonics as in the case of the square wave pulses. Accordingly, the two pulses 25 and 28 may serve to produce an to utilize pulses transmitted so that this is not" the case.
  • the oscillations produced in the tuned circuit will be such that the output signal will be similar to the side bands without any carrier, as inordinary suppressed carrier audio-modulation signalling. In such case, it is necessary to supply locally the carrier oscillations prior to detection in order that the envelope may be properly reproduced.
  • the receiving system in accordance with my invention is readily operable for reception of pulses regardless of the recurrence period as stated above. Accordingly, means may be provided at the transmitter for continuously varying this recurrence period. With such variation of recurrence, it is much more diflicult for an unauthorizedperson to intercept and translate the message or to produce jamming, pulses to obliterate the indication.
  • pulse formations representing periods of time comprise pairs of pulses variably, displaced with respect to one another, and said first named means comprises a shock excited tuned circuitand means for applying said pulses thereto.
  • a receiving system according to claim l wherein said first named means comprises ashock excited tuned circuit, and said second named means comprises the inherent damping characteristics of said tuned circuit.
  • a receiving system for receiving time modulated pulse energy in which the signal amplitudes are represented by the relative time dising each of said wave trains prior to the production of the succeeding wave train, and means for detecting said wave trains to produce the module.
  • a receiver for producing the modulation envelope offa received wave said wave comprising a seriesof pairs of pulses of radio frequency controlled in time position in accordance with a modulating wave, comprising means for receiving and reshaping said pulses, a shock excitation oscillatory circuit, means for causing excitation of said circuit to produce a wave train of a given frequency in response to reception of the first pulse of said pair, means responsive to the second pulse of said pair for modifying the amplitude of said wave train in accordance with the time position of said second pulse, means for substantially terminating said wave train prior to reception of the succeeding, pulse pair, and means for detecting said modified wave trains to reproduce said modulation envelope.
  • a receiver according to claim wherein said means for terminating said modified wave trains comprises the inherent damping characteristics of said circuit.
  • a receiver according to claim 5-wherein said means for terminatingsaid modified wave trains comprises, normall high impedance means connected across said circuit, and means responsive to received signals for effectively lowering the impedance of said normally high impedance wavetrains, and delay means for producing a'relative time delay between application of said pulse formations to said respective circuit means.
  • a receiver comprising a tuned circuit shock excited into oscillation by the first pulse of said pairs to produce Wave trains and excited by the second pulse of said pair to modify the produced wave trains in accordance with the spacing of said pulses.
  • a receiver comprising a pair of pulses
  • said first named circuit means comprising a tuned circuit shock excited into oscillation by the first pulse of said pairs to produce waves forming said trains and excited by the second pulse of said pair to modify the produced wavesin accordance with the spacing of said pulses
  • saidsecond named circuit means comprise a variable impedance shunt connected across said tuned circuit, and s means in said shunt connection for reducing said impedance in response to said applied pulse formations.
  • detector means for detecting said generated terminated wave trains to produce the envelope frequencies of said series of pulse formations.
  • a receiver comprising a pair of pulses, said first named circuit means comprising a tuned circuit shock excited into oscillation by the first pulse of said pairs to produce wave trains and excited by the second pulse of said pair to modify the produced wave trains in accordance with the spacing of said pulses, and said second named circuit means comprise a variable impedance shunt connected across said tuned circuit, and means in said shunt connection for reducing said impedance in response to said applied pulse formations, further comprising detector means for detecting said generated terminated wave trains to produce the envelope frequencies of said series of pulse formations.
  • a receiving system for receiving trains of pulse formations representing variable periods of time in accordance with a modulating envelope, means for producing wave trains representing'the initiation of said periods, means for modifying the amplitude of the produced Wave trains in accordance with the termination of said periods, and means for detecting the produced wave trains to obtain said modulating envelope.
  • a method according to claim 17 further inc uding the'step of substantially terminating each of said wave trains prior to initiation of the succeeding wavetrain.

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  • Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
  • Burglar Alarm Systems (AREA)
  • Near-Field Transmission Systems (AREA)
US461143A 1942-10-07 1942-10-07 Signal transmission system Expired - Lifetime US2416286A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
BE474051D BE474051A (fr) 1942-10-07
US461143A US2416286A (en) 1942-10-07 1942-10-07 Signal transmission system
GB17229/44A GB593139A (en) 1942-10-07 1944-09-08 Improvements in or relating to demodulating arrangements in time modulation electricpulse communication systems
FR951032D FR951032A (fr) 1942-10-07 1947-08-05 Systèmes récepteurs radioélectriques

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US461143A US2416286A (en) 1942-10-07 1942-10-07 Signal transmission system

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US2416286A true US2416286A (en) 1947-02-25

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FR (1) FR951032A (fr)
GB (1) GB593139A (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2455639A (en) * 1943-10-26 1948-12-07 Rca Corp Ground speed indicator utilizing doppler effect
US2474244A (en) * 1944-05-19 1949-06-28 Standard Telephones Cables Ltd Amplitude modulated time modulated pulse system
US2499534A (en) * 1950-03-07 A sorber
US2500536A (en) * 1947-02-27 1950-03-14 Bendix Aviat Corp Pulse-time demodulator
US2507176A (en) * 1945-03-15 1950-05-09 Hartford Nat Bank & Trust Co Receiver for pulse modulated waves
US2524251A (en) * 1948-10-26 1950-10-03 Philco Corp Pulse-modulation system
US2541986A (en) * 1945-03-15 1951-02-20 Claud E Cleeton Double pulse generator
US2591856A (en) * 1944-12-09 1952-04-08 Bell Telephone Labor Inc Pulse echo distance indicator
US2592572A (en) * 1946-08-16 1952-04-15 Malbon H Jennings Apparatus for recording and reproducing electrical communication currents
US2634411A (en) * 1947-01-09 1953-04-07 Wallace Navigational system
US2773180A (en) * 1952-11-10 1956-12-04 Boeing Co Alternating voltage modulation suppressors

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2061734A (en) * 1934-09-29 1936-11-24 Rca Corp Signaling system
US2086918A (en) * 1935-08-22 1937-07-13 Rca Corp Method of frequency or phase modulation
US2113214A (en) * 1936-10-29 1938-04-05 Rca Corp Method of frequency or phase modulation
US2273193A (en) * 1938-10-07 1942-02-17 Bell Telephone Labor Inc Wave transmission and shaping

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2061734A (en) * 1934-09-29 1936-11-24 Rca Corp Signaling system
US2086918A (en) * 1935-08-22 1937-07-13 Rca Corp Method of frequency or phase modulation
US2113214A (en) * 1936-10-29 1938-04-05 Rca Corp Method of frequency or phase modulation
US2273193A (en) * 1938-10-07 1942-02-17 Bell Telephone Labor Inc Wave transmission and shaping

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2499534A (en) * 1950-03-07 A sorber
US2455639A (en) * 1943-10-26 1948-12-07 Rca Corp Ground speed indicator utilizing doppler effect
US2474244A (en) * 1944-05-19 1949-06-28 Standard Telephones Cables Ltd Amplitude modulated time modulated pulse system
US2591856A (en) * 1944-12-09 1952-04-08 Bell Telephone Labor Inc Pulse echo distance indicator
US2507176A (en) * 1945-03-15 1950-05-09 Hartford Nat Bank & Trust Co Receiver for pulse modulated waves
US2541986A (en) * 1945-03-15 1951-02-20 Claud E Cleeton Double pulse generator
US2592572A (en) * 1946-08-16 1952-04-15 Malbon H Jennings Apparatus for recording and reproducing electrical communication currents
US2634411A (en) * 1947-01-09 1953-04-07 Wallace Navigational system
US2500536A (en) * 1947-02-27 1950-03-14 Bendix Aviat Corp Pulse-time demodulator
US2524251A (en) * 1948-10-26 1950-10-03 Philco Corp Pulse-modulation system
US2773180A (en) * 1952-11-10 1956-12-04 Boeing Co Alternating voltage modulation suppressors

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Publication number Publication date
BE474051A (fr)
GB593139A (en) 1947-10-09
FR951032A (fr) 1949-10-13

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