US2403726A - Pulse transmission system - Google Patents

Pulse transmission system Download PDF

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US2403726A
US2403726A US454660A US45466042A US2403726A US 2403726 A US2403726 A US 2403726A US 454660 A US454660 A US 454660A US 45466042 A US45466042 A US 45466042A US 2403726 A US2403726 A US 2403726A
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line
energy
circuit
wave
pulse
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US454660A
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Nils E Lindenblad
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RCA Corp
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RCA Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/10—Auxiliary devices for switching or interrupting
    • H01P1/15—Auxiliary devices for switching or interrupting by semiconductor devices

Definitions

  • the present invention relates to a method of and apparatus for producing carrier wave pulses of short duration.
  • Oneof the objects of the invention is to en able the production of substantially constant magnitude pulses from stored radio frequency energy
  • a pulse type transmitter in accordance with one embodiment of the invention, comprising an ultra high frequency oscillator O which feeds-into a low impedanceline TL of highQ.
  • Line TL is matched to a load, here shown as an antenna comprising a radiating dipole D in the focus of a parabolic reflector R.
  • a load here shown as an antenna comprising a radiating dipole D in the focus of a parabolic reflector R.
  • Across the line TL at point 'B there is a section of coaxial line TL which terminates in a cavity resonator CR, in turn resonant to the frequency of oscillator O.
  • the length of the circuit including line section 'I'-L',-as measured from the point 'B to the remote wall of the cavity resonatorl is an odd multiple including unityof a quarter wave at the frequency of oscillator O.
  • cavity resonator will be a high impedance at the end of line T'L' and thus produce a'short-circuit or extremely low impedance across the main transmission line at the location B. This is the normal condition of the system in the absence of any detuning efiects on the resonator.
  • the line TL acts as a storing device to store up energy fed into it by the oscillator 0 and has a length equivalent to half the length of space travel of the pulse to be transmitted.
  • Such a line generally speaking, has a large continuous phase distribution or phase angle, and may be made up of lumped inductances and capacitances, an ordinary coaxial line, or a wave guide.
  • the line TL has such an electrical length that the time required for a wave to travel thalength of the of compactness, the line TL can be coiled or of the type described in Fig. 1a of my copending application -Serial No. 441,311, filed May 1, 1942.
  • the energy stored up in the line TL is in the form of a standing wave, the nature of which is that it consists of'two wave components traveling in upposite directions. It will thus be seen that the line system must have such length that resonance exists during the building up or storage interval.
  • a gas dischargetube G having helium or argon gas
  • an ignition coil switch circuit Efed by .an alternating current source S I am able to detune the cavity resonator whenever the spark gap in the tube G breaks down.
  • This detuning of the cavity resonator CR-producedrby a discharge in tube G will change the short circuit at B to a high impedance, thus permitting the energy stored in; .line TL to how into the antenna as a burst of power.
  • the line TL and resonator CR can thus be looked at as a valve or a quarter wave modulation switch which controls the passage of energy .from the main transmission line TL to the load.
  • the interval between pulses, or between times of breakdown of the spark gap in tube G should be as large compared to the pulse duration as the output power to the antenna'is compared to the oscillator output.
  • the apparatus at E contains a switch for excit ing an ignition coil and can have any desired rate of closure. If desired, the switch can be eliminated, and sharp pulses employed to break down the spark-gap in the discharge tube G.
  • Fig. 2 is similar to Fig. 1 except that the gas discharge tube of Fig. l is replaced by a'sp'ark gap G. Both of the connections from apparatus E to the spark gap G" are capacitively coupled 'to there'sonator by means of metallic plates from a radio frequency standpoint. Such an arrangement constitutes in efiect a blocking condenser for the radio frequency energy in the resline is substantially one-half the duration of the onator.
  • oscillator O can be designed to generate oscillations in the Wavelength range of to cm.
  • I'he radiated pulses may be of the order of one-halfv microsecond or less and repeated at the rate of preferably not more than 1000 per second.
  • the output of oscillator O can be modulated or keyed, in which case the pulse rate from the system should be higher than the modulation frequency.
  • a pulse transmitter system including a power storing circuit in the form of a radio frequency wave carrying line circuit of large continuous phase distribution, a high frequency oscillator feeding energy into one end of aid circuit, a load at the other end of said circuit, and means coupled across said circuit at a point intermediate the ends of said circuit for enabling the energy stored in said circuit to be periodically utilized by said load, said line circuit having such parameters that the time it takes a wave to travel the length of the line circuit as measured from the end coupled to the oscillator to said point is equal to one-half th duration of the pulse delivered to said load.
  • a pulse transmitter including a power storing circuit in the form of a transmission line, a high frequency oscillator feeding energy into one end of said line, a load at the other end of said line, a section of line coupled across said transmission line at a point intermediate the ends thereof, a cavity resonator terminating said section at the end removed from said transmission line, said section and resonator having a length equivalent to one-quarter wavelength at the operating frequenc of said oscillator, a circuit for periodically detuning said resonator for alternately producin low and high impedances across said transmission line, whereby said section and resonator constitute a quarter wav modulation switch, said line having such parameters that the time it takes a wave to travel the length of the transmission line as measured from the end coupled to said oscillator to said point is equal to one-half the duration of the pulse delivered to said load.
  • a pulse type radio transmitter including a power storing circuit in the form of a low loss transmission line having such parameters that the time it takes a wave to travel the efiective length of the line is equal to one-half the duration of the pulse to be generated, a source of carrierwave energy coupled to said line near one end thereof, an antenna coupled to the other end of said line and matched to said line from an impedance standpoint, and a modulation switch whoselength is electrically an odd multiple including unity of a quarter wave at the frequency of said source coupled across said line at a point near said antenna.
  • A- pulse type radio transmitter including a power storing circuit in the form of a low loss transmission line havin such parameters that the time it takes a wave to travel the effective length of the line is equal to one-half the duration of the pulse to be generated, an ultra high frequency generator of oscillations whose wavelength is of the order of at least several centimeters coupled to said line near one end, a directive antenna coupled to the other end of said line and matched to said line from an impedance standpoint, and. a quarter wave valve circuit for enabling the periodic utilization of the energy stored in said line by saidantenna, said quarter wave circuit, includinga resonator coupled by means of a suitable feeder system across said line at a point intermediate the ends thereof, there being means fo periodically detuning said resonator.
  • a radio, system having a transmitter arranged to store up alternating current energy and to transmit periodically pulses of stored alternating current energy 'for time periods short compared to the time intervals between transmitted pulses, said system including an energy storing circuitin the form of a section of coaxial transmission line having such parameters that the time it takes a wave to travel the effective length of said line is equal to one-half the duration of the pulses generated.
  • a radio system having a transmitter arranged to store up energy and to transmit periodically pulses of stored energy for time periods short compared to the time intervals between transmitted pulses, said system including an energy storing circuit in the form of asection of coaxial transmission line having such parameters that the time it takes a wave to travel the effective length of said line is equal toone-half the duration of the pulses generated, a. source of high frequency energy coupled to said line near one end thereof, an antenna coupled to said line at the other end thereof and matched thereto, and means coupled across said-line between said antenna and said source for periodically shunting said line with a high and a low impedance for enabling periodic utilization of the energy stored in said line.
  • a radiosystem having a transmitter arranged to store up energy and to transmit periodically pulses of stored energy for time periods short. compared to the time intervals between transmitted pulses, said system including an energ storing'circuit in the form of a line whose effective length is such that the time required for a wave to travelthe length of the line is substantially equal to one-half the duration of the pulses generated.
  • a radio system having a transmitter arranged tostore up energy and to transmit periodically pulses of stored energy for time periods short compared to the time intervals between transmitted pulses, said system including an energy storing circuit in the form of a line whose effective length is such that the time required for a wave to travel the length of the line is substantially equal to one-half the duration of the pulses generated, and a load coupled to one end of said line and matched to said linefrom an impedance t nd NILS E, LINDENBLAD,

Description

y 1946. N. E. LINDENBLAD 0 PULSE TRANSMISSIONQSYSTEM Filed Aug. 13, 1942 Tlzllp ALTERNXT/NG 5 54s DISCHARGE Cums/ T 7/55 I "5 [GMT/0N Con. T
I F n- C I A NTENNA M- T T Q I TL 5 I l V H/qh' fasqualvcy OSCILLATOA 634/?! 6'13 gin m fEsoA/AroR I PARAMETERS DETERMI/VES DURATION or am PULSES 0 FFE UEMY INVENTOR v OSCILLATOR Na fxlb/gsgamo.
ATTORNEY Patented July 9, 1946 s PATENT OFFICE.
.PULSE TRANSMISSION SYSTEM ..Nils E. Lindenblad, Port Jefferson, N. Y., assignor to Radio Corporation of America, a corporation' of Delaware Application August 13, 1942, Serial No. 454,660
10 Claims.
The present invention relates to a method of and apparatus for producing carrier wave pulses of short duration.
Oneof the objects of the invention is to en able the production of substantially constant magnitude pulses from stored radio frequency energy; J
.A more detailed description of the invention follows in conjunction with a drawing, wherein Figs. land .2 illustrate two different embodiments of the invention.
The same parts are represented by the same reference numerals throughout the two figures of the drawing.
Referring to Fig. 1 in more detail, there is shown a pulse type transmitter in accordance with one embodiment of the invention, comprising an ultra high frequency oscillator O which feeds-into a low impedanceline TL of highQ. Line TL is matched to a load, here shown as an antenna comprisinga radiating dipole D in the focus of a parabolic reflector R. Across the line TL at point 'B there is a section of coaxial line TL which terminates in a cavity resonator CR, in turn resonant to the frequency of oscillator O. The length of the circuit including line section 'I'-L',-as measured from the point 'B to the remote wall of the cavity resonatorlis an odd multiple including unityof a quarter wave at the frequency of oscillator O.
In view of the length'of this quarter wave circuit T'L', CR, it will be seen that when the cavity resonator is excited 'by virtue of the small amount Y pulse to be generated and radiated. For the sake of energy in line T'L' obtained from line TL, the
cavity resonator will be a high impedance at the end of line T'L' and thus produce a'short-circuit or extremely low impedance across the main transmission line at the location B. This is the normal condition of the system in the absence of any detuning efiects on the resonator.
The line TL acts as a storing device to store up energy fed into it by the oscillator 0 and has a length equivalent to half the length of space travel of the pulse to be transmitted. Such a line, generally speaking, has a large continuous phase distribution or phase angle, and may be made up of lumped inductances and capacitances, an ordinary coaxial line, or a wave guide. Thus, if it lsdesirEdthat the pulse to be radiated by the antenna be one-tenthof a microsecond duration, 'thel'ine TLsho'uIdbe about fifty feet long electrically; or putting it in other Words, the line TL has such an electrical length that the time required for a wave to travel thalength of the of compactness, the line TL can be coiled or of the type described in Fig. 1a of my copending application -Serial No. 441,311, filed May 1, 1942. The energy stored up in the line TL is in the form of a standing wave, the nature of which is that it consists of'two wave components traveling in upposite directions. It will thus be seen that the line system must have such length that resonance exists during the building up or storage interval.
By means of suitable apparatus such as a gas dischargetube G (having helium or argon gas) and an ignition coil switch circuit Efed by .an alternating current source S, I am able to detune the cavity resonator whenever the spark gap in the tube G breaks down. This detuning of the cavity resonator CR-producedrby a discharge in tube G will change the short circuit at B to a high impedance, thus permitting the energy stored in; .line TL to how into the antenna as a burst of power. The line TL and resonator CR can thus be looked at as a valve or a quarter wave modulation switch which controls the passage of energy .from the main transmission line TL to the load.
By making the losses in line TL reasonably low, there is obtained a constant amplitude pulse which has a time duration corresponding to twice the length of line IL from points B to C, for utilization by th antenna. Putting it in other words, there isa substantially uniform flow of energy from line TL to the antenna until all the stored energy in line TL is used up, while the resonator-is detuned. The length of line TL between points C and B should be a multiple of a half wave.
The interval between pulses, or between times of breakdown of the spark gap in tube G, should be as large compared to the pulse duration as the output power to the antenna'is compared to the oscillator output.
The apparatus at E contains a switch for excit ing an ignition coil and can have any desired rate of closure. If desired, the switch can be eliminated, and sharp pulses employed to break down the spark-gap in the discharge tube G.
Fig. 2 is similar to Fig. 1 except that the gas discharge tube of Fig. l is replaced by a'sp'ark gap G. Both of the connections from apparatus E to the spark gap G" are capacitively coupled 'to there'sonator by means of metallic plates from a radio frequency standpoint. Such an arrangement constitutes in efiect a blocking condenser for the radio frequency energy in the resline is substantially one-half the duration of the onator.
, oscillator O can be designed to generate oscillations in the Wavelength range of to cm. I'he radiated pulses may be of the order of one-halfv microsecond or less and repeated at the rate of preferably not more than 1000 per second.
If desired, the output of oscillator O can be modulated or keyed, in which case the pulse rate from the system should be higher than the modulation frequency.
What is claimed is:
1. A pulse transmitter system including a power storing circuit in the form of a radio frequency wave carrying line circuit of large continuous phase distribution, a high frequency oscillator feeding energy into one end of aid circuit, a load at the other end of said circuit, and means coupled across said circuit at a point intermediate the ends of said circuit for enabling the energy stored in said circuit to be periodically utilized by said load, said line circuit having such parameters that the time it takes a wave to travel the length of the line circuit as measured from the end coupled to the oscillator to said point is equal to one-half th duration of the pulse delivered to said load.
2. A pulse transmitter including a power storing circuit in the form of a transmission line, a high frequency oscillator feeding energy into one end of said line, a load at the other end of said line, a section of line coupled across said transmission line at a point intermediate the ends thereof, a cavity resonator terminating said section at the end removed from said transmission line, said section and resonator having a length equivalent to one-quarter wavelength at the operating frequenc of said oscillator, a circuit for periodically detuning said resonator for alternately producin low and high impedances across said transmission line, whereby said section and resonator constitute a quarter wav modulation switch, said line having such parameters that the time it takes a wave to travel the length of the transmission line as measured from the end coupled to said oscillator to said point is equal to one-half the duration of the pulse delivered to said load.
3. A pulse type radio transmitter including a power storing circuit in the form of a low loss transmission line having such parameters that the time it takes a wave to travel the efiective length of the line is equal to one-half the duration of the pulse to be generated, a source of carrierwave energy coupled to said line near one end thereof, an antenna coupled to the other end of said line and matched to said line from an impedance standpoint, and a modulation switch whoselength is electrically an odd multiple including unity of a quarter wave at the frequency of said source coupled across said line at a point near said antenna.
4. A- pulse type radio transmitter including a power storing circuit in the form of a low loss transmission line havin such parameters that the time it takes a wave to travel the effective length of the line is equal to one-half the duration of the pulse to be generated, an ultra high frequency generator of oscillations whose wavelength is of the order of at least several centimeters coupled to said line near one end, a directive antenna coupled to the other end of said line and matched to said line from an impedance standpoint, and. a quarter wave valve circuit for enabling the periodic utilization of the energy stored in said line by saidantenna, said quarter wave circuit, includinga resonator coupled by means of a suitable feeder system across said line at a point intermediate the ends thereof, there being means fo periodically detuning said resonator.
5. A radio, system having a transmitter arranged to store up alternating current energy and to transmit periodically pulses of stored alternating current energy 'for time periods short compared to the time intervals between transmitted pulses, said system including an energy storing circuitin the form of a section of coaxial transmission line having such parameters that the time it takes a wave to travel the effective length of said line is equal to one-half the duration of the pulses generated.
6. A radio system having a transmitter arranged to store up energy and to transmit periodically pulses of stored energy for time periods short compared to the time intervals between transmitted pulses, said system including an energy storing circuit in the form of asection of coaxial transmission line having such parameters that the time it takes a wave to travel the effective length of said line is equal toone-half the duration of the pulses generated, a. source of high frequency energy coupled to said line near one end thereof, an antenna coupled to said line at the other end thereof and matched thereto, and means coupled across said-line between said antenna and said source for periodically shunting said line with a high and a low impedance for enabling periodic utilization of the energy stored in said line. l l
7. A pulse transmitter in accordancewith claim 1, characterized in this that said radio frequency wave carrying circuit of large continuous phase distribution is a two-conductor line.
' 8. A pulse transmitter in accordance with claim 1, characterized inthis that said radio frequency wave carrying circuit of large continuous phase distribution is a wave guide.
9. A radiosystem having a transmitter arranged to store up energy and to transmit periodically pulses of stored energy for time periods short. compared to the time intervals between transmitted pulses, said system including an energ storing'circuit in the form of a line whose effective length is such that the time required for a wave to travelthe length of the line is substantially equal to one-half the duration of the pulses generated.
10. A radio system having a transmitter arranged tostore up energy and to transmit periodically pulses of stored energy for time periods short compared to the time intervals between transmitted pulses, said system including an energy storing circuit in the form of a line whose effective length is such that the time required for a wave to travel the length of the line is substantially equal to one-half the duration of the pulses generated, and a load coupled to one end of said line and matched to said linefrom an impedance t nd NILS E, LINDENBLAD,
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2460755A (en) * 1945-06-30 1949-02-01 Bell Telephone Labor Inc Receiver protective circuit for pulse transmission systems
US2564660A (en) * 1946-08-02 1951-08-21 Ollie J Allen Means for interconnecting radio and telephone systems
US2572088A (en) * 1945-12-22 1951-10-23 Sperry Corp Ultra high frequency coded transmitter system utilizing stored energy received by the system
US2632854A (en) * 1947-12-18 1953-03-24 Westinghouse Electric Corp Resonant cavity drive
US4009444A (en) * 1974-08-30 1977-02-22 The United States Of America As Represented By The United States Energy Research And Development Administration Passive radio frequency peak power multiplier

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2460755A (en) * 1945-06-30 1949-02-01 Bell Telephone Labor Inc Receiver protective circuit for pulse transmission systems
US2572088A (en) * 1945-12-22 1951-10-23 Sperry Corp Ultra high frequency coded transmitter system utilizing stored energy received by the system
US2564660A (en) * 1946-08-02 1951-08-21 Ollie J Allen Means for interconnecting radio and telephone systems
US2632854A (en) * 1947-12-18 1953-03-24 Westinghouse Electric Corp Resonant cavity drive
US4009444A (en) * 1974-08-30 1977-02-22 The United States Of America As Represented By The United States Energy Research And Development Administration Passive radio frequency peak power multiplier

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