US3612899A - Generator for short-duration high-frequency pulse signals - Google Patents

Generator for short-duration high-frequency pulse signals Download PDF

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Publication number
US3612899A
US3612899A US65551A US3612899DA US3612899A US 3612899 A US3612899 A US 3612899A US 65551 A US65551 A US 65551A US 3612899D A US3612899D A US 3612899DA US 3612899 A US3612899 A US 3612899A
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Prior art keywords
transmission line
line means
frequency
switch
pulse
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US65551A
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English (en)
Inventor
Gerald F Ross
Joseph D De Lorenzo
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Unisys Corp
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Sperry Rand Corp
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03K—PULSE TECHNIQUE
    • H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
    • H03K3/80—Generating trains of sinusoidal oscillations

Definitions

  • the invention pertains to means for producing pulses of high-frequency or microwave sine wave electromagnetic signals of duration of the order-of one nanosecond and more particularly to apparatus for producing such pulse signals having abrupt initial rise and terminal fall characteristics with sub stantially no energy emission before or following the pulse.
  • the present invention is an apparatus for generating pulsemodulated, high-frequency carriersignals having pulse durations of the order of a nanosecond and-having sharply rectangular envelopes.
  • the invention preferably employs excitation of TEM-mode electromagnetic wave propagation in a novel pulse-forming network having time-limited response characteristics in response to a gated pulse or step modulated highfrequency input wave.
  • FIG. I is a schematic circuit representation of one form of the invention.
  • FIG. 2 is an explanatory graph used in understanding FIG. 1.
  • FIGS. 3, 4, and 5 are graphs showing output waveforms generated by variously adjusting the circuit of FIG. 1'.
  • FIGS. 6 and 7 are equivalent circuits used in explaining the operationof the circuit of FIG. 1.
  • FIG. 8 is, like FIG. 1, a schematic circuit representation of one form of the invention.
  • FIG. 9 is a partially schematic top view of one preferred form of the invention.
  • FIG. 10 is a partially sectioned top view of a presently preferred form of the invention.
  • the invention is a high-frequency transmission line circuit for generatint! impulse modulated signals having an impulse envelope duration of the order of a nanosecond.
  • the generator employs a pulse forming network having a time-limited response driven by a source of step modulated high-frequency energy. Passive properties inherent in the network may be employed to cause sharp terminal fall of the impulse for production of a sharply rectangular pulse envelope.
  • a lossless two-wire transmission line 3, 31 having a surge or characteristic impedance 2 extends a distance D between impedance reference planes 4 and 5.
  • Stub transmission line 7, .741 has a surge impedance Z. and fonns a pulseforming network 10 in cooperation with the main transmission line 3, 3a.
  • Various known types of. low loss, nondispersive transmission lines may be used to form lines 3, 3a and 7, 7a, including transmission lines that propagate traveling highfrequency or microwave signals in nondispersive modes, such as in the TEM mode.
  • the normalized surge or characteristic impedance Z, of transmission line 3, 3a may be 1 ohm, while that of line 7, 7a must have a characteristic impedance onehalf that of line 3, or 0.5 ohms.
  • Networks 10 may be excited at its input terminals in plane 4 by an impulse or repetitive train of impulses furnished at said input by a known-type of impulse generator I1 having an internal resistance indicated by resistor 12 of R, ohms. A normalized value of 1 ohm may be chosen for the parameter R,.
  • An impulse supplied by generator 11 travels through pulseforming network 10 to a resistive or terminating load 15 which may be a radiating antenna or other matched utilization device.
  • Load 15 has a resistance R which may also have a normalized value of 1 ohm.
  • the significance of such a type of time-limited response becomes evident uponexamination of the output of pulse-forming network 10 for a step-modulated excitation having a nominal carrier frequency f centered at f,,, where f,, may take values such and where k is an integer.
  • the output of network 10 for t T seconds is identically zero, regardless of the starting phase of the sinusoidal input impulse.
  • the time period following the end of interval T represents a forbidden era in which the input wave cannot contribute energy to an output signal.
  • FIG. 4 like FIG. 3, represents a pattern in which the exciting pulse starts with zero phase, but the value of f,, is now 9/2T.
  • the same forbidden region is represented by dotted line waveforms.
  • pulse-forming network 10 has been somewhat idealized in the sense that certain practical considerations have been neglected. Most important, particularly for frequencies above those lying in the X-band, the leakage capacity of the gating switch within generator 11 which controls the start and stop of the pulse emanating form signal source 11 has been neglected. According to the present invention, the effects of switch leakage are recognized and are beneficially used.
  • pulse forming network 10 is connected to the sine wave generator 11a when switch 22 is open through the generators source resistance 12 and the leakage capacity of switch 22, which capacitance may be represented by a capacitor 23 of value C,.
  • the output voltage a(t) from network 10 appearing across matched termination 15 is zero regardless of the values of C, and V, because of the effective short circuit imposed by stub transmission line 3, at f--f,,.
  • the magnitude and carrier phase of the output pulse depends critically on the steady state voltage V, across leakage capacitor 23 at the time at which switch 22 is to be closed.
  • Z is defined as the steady state sinusoidal driving point impedance as measured at the input port of the pulse forming network at any frequency f.
  • the value of the steady state driving point impedance Z.,, for network 10 is:
  • the factor Q is the conventional quality factor of the resonating circuit.
  • the voltage V is given by:
  • the signal a(t) closely resembles the pulse wave shown in FIG. 5.
  • the unsynchronized step modulated sine wave generator 11 of FIG. 1 may be any convenient relatively stable high-frequency oscillator, and it may internally include a series connected controlling or gating switch 22 which may be either a singlepole, single throw mercury-wetted mechanical switch or a voltage controlled semiconductor switch of conventional nature. Switches suitable for such applications are illustrated, for example, in the pending G. F. Ross Pat. application Ser. No. 843,945, entitled High Frequency Switch" and filed July 23, 1969, now U.S. Pat. No. 3,569,877, issued Mar. 9, 1971, as well as in the H. C. Maguire Pat. application Ser. No.
  • FIG. 8 represents schematically the form of a two-wire transmission line system in a practical instrumentation of the invention and is further to be discussed in connection with the apparatus of FIG. 9 which is illustrated in the form of a coaxial transmission line system.
  • FIG. 8 is significantly similar to part of FIG. 1, and corresponding parts are identified by similar reference numerals.
  • two-wire transmission line 3, 3a extends between impedance reference planes 4 and 5 and has branching from it a two-wire opemcircuited transmission line 7, 7a of length L whose junction with line 3, 3a is located in reference plane 6 a distance d from plane 4, as previously defined.
  • the value d is again adjusted substantially to the m d called for by equation (3).
  • FIG. 9 One practical embodiment of the invention is shown in FIG. 9 as having an internally impulse modulated generator 111 similar to generator 11 of FIG. 1 and coupled at a reference plane 104 to a coaxial transmission line network 110a whose output impulse wave a(t) is coupled at reference plane 105 to matched termination 115.
  • parts of network 110a corresponding to parts of network a of FIG. 8 have similar reference numerals with the factor of I00 added to them.
  • the network 110a is conveniently formed of readily available coaxial transmission line components to form a cross-shaped configuration. It includes a main coaxial transmission line 103, 103a whose center conductor 103 is connected to generator 111 and to terminal load 115. The opposite lead of generator 111 and of load 115 are grounded, as is the outer conductor 103a of line 103, 103a.
  • the network is formed with radially or oppositely branching coaxial lines 107, 107a and 117, 117a. The latter are shown cut away at junction 125 lying in plane 106 to emphasize the joint connection at point 125 of inner conductors 107 and 117 to inner conductor 103 of the main transmission line 103, 103a.
  • FIG. 10 represents a modification ll0b of the network 110a of FIG. 9 having additional features desirable in certain applications.
  • the structure is electrically equivalent to that of FIG. 9, but radially extending coaxial lines 107, 107a and 117, 117a, which may be in the from of flexible coaxial cables, are bent into a generally circular loop. Then, the respective opencircuited ends 123 and 123a of lines 107, 107a and 117, 117a are directly joined in conductive relation, as in the plane 126 of FIG. 10. It is understood that part of the loop lies above the plane of the drawing of FIG. 10.
  • FIGS. 9 and 10 Operation of FIGS. 9 and 10 is similar, since all signals again travel the same distances in both embodiments. Those signals which return to junction 125 in FIG. 9 from the stub lines along the same paths as they originally left it, return thereto in FIG. 10 along the opposite branch transmission line. In the apparatus of FIGS. 9 and 10, all transmission line elements may conveniently be commercially standard 50-ohm components.
  • An additional advantage of the FIG. 10 structure is that the output pulse duration is dependent upon the length of a single continuous cable loop. F Urther, no leadage of energy can occur because of an imperfect open circuit 123 or 1230 and counterflowing signals must travel over equal paths.
  • first high-frequency transmission line means having a predetermined characteristic impedance Z, and input and output means,
  • high-frequency sine wave oscillator means for supplying a train of high-frequency sine wave cycles at said input means
  • said distance d so adjusted as substantially to provoke resonance between said input means and the leakage capacitance C, of said switch.
  • B fJ and where f, is the operating frequency of said oscillator means and c is the velocity of wave propagation is said first transmission line means.
  • said open-circuited branch transmission line means joined to said first transmission line means comprises radially extending coaxial transmission line means open-circuited at ends remote from said first transmission line means.

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US65551A 1970-08-20 1970-08-20 Generator for short-duration high-frequency pulse signals Expired - Lifetime US3612899A (en)

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CA (1) CA938004A (ref)
DE (1) DE2141832A1 (ref)
FR (1) FR2104509A5 (ref)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4367415A (en) * 1979-02-24 1983-01-04 Hewlett-Packard Gmbh Pulse generator circuit
US4864258A (en) * 1988-05-02 1989-09-05 The United States Of America As Represented By The Secretary Of The Army RF envelope generator
US6026125A (en) * 1997-05-16 2000-02-15 Multispectral Solutions, Inc. Waveform adaptive ultra-wideband transmitter
US6351246B1 (en) 1999-05-03 2002-02-26 Xtremespectrum, Inc. Planar ultra wide band antenna with integrated electronics
US20030053555A1 (en) * 1997-12-12 2003-03-20 Xtreme Spectrum, Inc. Ultra wide bandwidth spread-spectrum communications system
US6590545B2 (en) 2000-08-07 2003-07-08 Xtreme Spectrum, Inc. Electrically small planar UWB antenna apparatus and related system
US20070196621A1 (en) * 2006-02-02 2007-08-23 Arnold Frances Sprayable micropulp composition
US20070242735A1 (en) * 2006-01-31 2007-10-18 Regents Of The University Of Minnesota Ultra wideband receiver
US7506547B2 (en) 2004-01-26 2009-03-24 Jesmonth Richard E System and method for generating three-dimensional density-based defect map
US7616676B2 (en) 1998-12-11 2009-11-10 Freescale Semiconductor, Inc. Method and system for performing distance measuring and direction finding using ultrawide bandwidth transmissions
US20100026101A1 (en) * 2005-11-09 2010-02-04 Bae Systems Information And Electronic Systems Integration Inc. Bipolar pulse generators with voltage multiplication
USRE44634E1 (en) 1997-05-16 2013-12-10 Multispectral Solutions, Inc. Ultra-wideband receiver and transmitter

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3402370A (en) * 1965-11-30 1968-09-17 Air Force Usa Pulse generator

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3402370A (en) * 1965-11-30 1968-09-17 Air Force Usa Pulse generator

Cited By (25)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4367415A (en) * 1979-02-24 1983-01-04 Hewlett-Packard Gmbh Pulse generator circuit
US4864258A (en) * 1988-05-02 1989-09-05 The United States Of America As Represented By The Secretary Of The Army RF envelope generator
US6690741B1 (en) * 1997-05-16 2004-02-10 Multispectral Solutions, Inc. Ultra wideband data transmission system and method
US6026125A (en) * 1997-05-16 2000-02-15 Multispectral Solutions, Inc. Waveform adaptive ultra-wideband transmitter
USRE44634E1 (en) 1997-05-16 2013-12-10 Multispectral Solutions, Inc. Ultra-wideband receiver and transmitter
US7408973B2 (en) 1997-12-12 2008-08-05 Freescale Semiconductor, Inc. Ultra wide bandwidth spread-spectrum communications system
US6700939B1 (en) 1997-12-12 2004-03-02 Xtremespectrum, Inc. Ultra wide bandwidth spread-spectrum communications system
US6901112B2 (en) 1997-12-12 2005-05-31 Freescale Semiconductor, Inc. Ultra wide bandwidth spread-spectrum communications system
US6931078B2 (en) 1997-12-12 2005-08-16 Freescale Semiconductor, Inc. Ultra wide bandwidth spread-spectrum communications systems
US20030053555A1 (en) * 1997-12-12 2003-03-20 Xtreme Spectrum, Inc. Ultra wide bandwidth spread-spectrum communications system
US8451936B2 (en) 1998-12-11 2013-05-28 Freescale Semiconductor, Inc. Method and system for performing distance measuring and direction finding using ultrawide bandwidth transmissions
US7616676B2 (en) 1998-12-11 2009-11-10 Freescale Semiconductor, Inc. Method and system for performing distance measuring and direction finding using ultrawide bandwidth transmissions
US6351246B1 (en) 1999-05-03 2002-02-26 Xtremespectrum, Inc. Planar ultra wide band antenna with integrated electronics
US6590545B2 (en) 2000-08-07 2003-07-08 Xtreme Spectrum, Inc. Electrically small planar UWB antenna apparatus and related system
US7856882B2 (en) 2004-01-26 2010-12-28 Jesmonth Richard E System and method for generating three-dimensional density-based defect map
US7506547B2 (en) 2004-01-26 2009-03-24 Jesmonth Richard E System and method for generating three-dimensional density-based defect map
US8093761B2 (en) 2005-11-09 2012-01-10 Bae Systems Information And Electronic Systems Integration Inc. Bipolar pulse generators with voltage multiplication
US7986060B2 (en) * 2005-11-09 2011-07-26 Bae Systems Information And Electronic Systems Integration Inc. Bipolar pulse generators with voltage multiplication
US20100026101A1 (en) * 2005-11-09 2010-02-04 Bae Systems Information And Electronic Systems Integration Inc. Bipolar pulse generators with voltage multiplication
US8093760B2 (en) 2005-11-09 2012-01-10 Bae Systems Information And Electronic Systems Integration Inc. Bipolar pulse generators with voltage multiplication
US8125106B2 (en) 2005-11-09 2012-02-28 Bae Systems Information And Electronic Systems Integration Inc. Bipolar pulse generators with voltage multiplication
US8183716B2 (en) 2005-11-09 2012-05-22 Bae Systems Information And Electronic Systems Integration Inc. Bipolar pulse generators with voltage multiplication
US8098707B2 (en) 2006-01-31 2012-01-17 Regents Of The University Of Minnesota Ultra wideband receiver
US20070242735A1 (en) * 2006-01-31 2007-10-18 Regents Of The University Of Minnesota Ultra wideband receiver
US20070196621A1 (en) * 2006-02-02 2007-08-23 Arnold Frances Sprayable micropulp composition

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Publication number Publication date
FR2104509A5 (ref) 1972-04-14
DE2141832A1 (de) 1972-02-24
CA938004A (en) 1973-12-04

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