US3452429A - Compensation of coaxial cables - Google Patents

Compensation of coaxial cables Download PDF

Info

Publication number
US3452429A
US3452429A US577919A US3452429DA US3452429A US 3452429 A US3452429 A US 3452429A US 577919 A US577919 A US 577919A US 3452429D A US3452429D A US 3452429DA US 3452429 A US3452429 A US 3452429A
Authority
US
United States
Prior art keywords
cable
compensation
coaxial
voltage standing
locations
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US577919A
Inventor
Arthur Liebscher
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.)
Electronics Inc of Pennsylvania
Original Assignee
Electronics Inc of Pennsylvania
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Electronics Inc of Pennsylvania filed Critical Electronics Inc of Pennsylvania
Application granted granted Critical
Publication of US3452429A publication Critical patent/US3452429A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01PWAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P5/00Coupling devices of the waveguide type
    • H01P5/02Coupling devices of the waveguide type with invariable factor of coupling
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B11/00Communication cables or conductors
    • H01B11/18Coaxial cables; Analogous cables having more than one inner conductor within a common outer conductor
    • H01B11/1895Particular features or applications
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49002Electrical device making
    • Y10T29/49004Electrical device making including measuring or testing of device or component part
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10TTECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00Metal working
    • Y10T29/49Method of mechanical manufacture
    • Y10T29/49002Electrical device making
    • Y10T29/49016Antenna or wave energy "plumbing" making

Definitions

  • This invention relates to the compensation of coaxial interconnecting cables of any desired length.
  • a well known type of coaxial cable includes an inner conductor surrounded by an insulating layer which is in turn surrounded by an outer conductor in the form of a braided cover or tubing which is corrugated or spirally Wound and with an outer insulating and protecting layer.
  • These cables include connectors, and those known as Military Type N and BNC.
  • Various plug type end connections for such cables are employed, these commonly including a plug and jack or a plug and socket, with a pin and socket connection for the inner conductor.
  • Coaxial cables with their end connectors dependent upon their use, must have a voltage standing wave ratio, referred to as VSWR, below a predetermined limit for satisfactory performance of such cable.
  • VSWR voltage standing wave ratio
  • Sweep frequency methods are commonly used in production testing, wherein the voltage standing wave ratio or VSWR response of an entire band of frequencies is simultaneously depicted as an oscilloscope pattern. This permits observation of dynamic changes in the VSWR response due to mechanical changes or adjustments in cable or connector construction.
  • FIG. 3 is a transverse sectional view taken approximately on the line 3-3 of FIG. 2;
  • FIG. 4 is a drawing of an oscilloscope pattern for a particular uncompensated coaxial cable and with the same cable compensated.
  • the particular coaxial cable to be compensated has a resistance load applied to one end thereof.
  • a sweep generator is coupled to a wave guide through a first transducer and calibrating means and connected to the cable, with a second transducer interposed between the wave guide and the cable.
  • the wave guide has a directional coupler which picks up the combination of a reflected wave and a forward wave which is detected for observation on an oscilloscope.
  • Pressure is preliminarily applied to the cable by squeezing the cable around the circumference at locations spaced from the connectors and as determined visually on the oscilloscope for the best reduction of VSWR, and a permanent correction is preferably then applied at the selected locations.
  • the correction can be applied in any suitable manner to effect a permanent deformation at one or more selected locations, one suitable correction being provided by compressing and permanently deforming continuous bands or rings into engagement with the exterior of the cable.
  • a coaxial cable 10 having end connections 11 and 12 has a resistance load 13 connected thereto.
  • the cable 10 may be of the type which includes an inner or central conductor 14 surrounded by an insulating and spacing layer 15 which in turn is surrounded by a conducting layer 16 with a surrounding insulating and protecting layer 17.
  • the conducting layer 16 may be of single or double braided metallic strands, may be of metallic tubing, and may be of metal corrugated or spirally wound.
  • a sweep generator 20 of any suitable type is provided, having a sweep range determined by the ultimate use to be made of the cable 10.
  • the range may be from megahertz (megacycles) to high gigahertz (gigacycles) of a level which the cable 10 can carry.
  • the frequencies may be from 4 to 12 gigacycles.
  • the sweep generator 20 is connected through a filter or attenuating device 21 and through a transducer 22 to one end of a wave guide 23 to which, at the opposite end, the cable 10 is connected through a transducer 24.
  • the wave guide 23 preferably includes a directional coupler 25 which is connected in any suitable manner,
  • the cable 10 before the attachment thereto of the end connectors 11 and 12 has a plurality of loose continuous rings or bands 30 slid thereon.
  • the bands 30 are of copper, aluminum or any other material of adequate strength and capable of permanent deformation as hereinafter explained.
  • the sweep generator 10 is activated to apply the desired frequency range, say 4 to 8 gigacycles, 8 to 12 gigacycles or 4 to 12 gigacycles through the filter 21 and transducer 22, wave guide 23 and transducer 24 to the loaded cable 10.
  • the directional coupler 25 will pick up a combination of a reflected wave and a forward wave and the trace of this is available, after detection by the detector 26, for observation at the oscilloscope 27.
  • this figure represents the screen of the oscilloscope 27, with ordinates representative of the voltage standing wave ratio, and the abscissas repreabove it is preferred to correct first for the end of the sentative of the progression of the combination wave.
  • the i curve 32 shown as a broken line, may be taken as a curve showing the condition of the cable 10 as manufactured and with the connectors 11 and 12 thereon. If an acceptable voltage standing wave ratio of the order of 1.2 be taken as the standard, it will be noted that the peaks of the curve 32 extend beyond that ratio value.
  • the compensation is effected by compressing the cable 10 at one or more locations with any desired implement, such as pliers, and observing the effect of the compressing as shown by the oscilloscope trace.
  • the locations which tend to improve the ratio and flatten out curve 32 are determined by trial and error both as to the distance from the connectors 11 and 12 and as to the extent of this initial compression.
  • the rings are preferably moved to the lengthwise locations on the cable 10 as indicated by the initial compressing and are then compressed by any suitable compressing or collapsing tool.
  • the curve 33 shows a trace obtained for a particular cable 10 having an initial trace at 32, after compensation.
  • an elfort is made to reduce all the high points but the locations giving the best reduction are preferably used.
  • the rings 30 will not ordinarily be required.
  • the method of compensating a coaxial cable to an acceptable voltage standing wave ratio which comprises:
  • said deformation includes an initial trial deformation.
  • said ring is squeezed to provide a permanent squeeze deformation of said outer conductor.
  • said deformation includes an additional subsequent permanent deformation affecting the voltage standing wave ratio as determined upon reversal of the cable.

Landscapes

  • Measurement Of Resistance Or Impedance (AREA)

Description

- July 1 1969 A. LI EBSCHER COMPENSATION OF COAXIAL CABLES Filed Sept. 8, 1966 M/VENTOI? ARTHUR L/EBSCHER N WE u YQQR bwnsQ ATTORNEY I United States Patent 3,452,429 COMPENSATION OF COAXIAL CABLES Arthur Liebscher, Jenkintown, Pa. Electronics Inc. of Pennsylvania, 2440 Maryland Road, Willow Grove, Pa. 19090) Filed Sept. 8, 1966, Ser. No. 577,919 Int. Cl. G01r 27/26 U.S. Cl. 29593 6 Claims ABSTRACT OF THE DISCLOSURE A method of compensating coaxial cable in which the outer conductor of the cable is squeeze deformed at selected locations to modify the capacitive relation of the outer conductor to the inner conductor and thereby bring the voltage standing wave ratio within predetermined limits.
This invention relates to the compensation of coaxial interconnecting cables of any desired length.
A well known type of coaxial cable includes an inner conductor surrounded by an insulating layer which is in turn surrounded by an outer conductor in the form of a braided cover or tubing which is corrugated or spirally Wound and with an outer insulating and protecting layer. These cables include connectors, and those known as Military Type N and BNC. Various plug type end connections for such cables are employed, these commonly including a plug and jack or a plug and socket, with a pin and socket connection for the inner conductor.
Coaxial cables with their end connectors, dependent upon their use, must have a voltage standing wave ratio, referred to as VSWR, below a predetermined limit for satisfactory performance of such cable.
Various tests have heretofore been applied to determine the VSWR, including the time domain test which sends a pulse down the line. Some of the pulse energy is refiected back and the equipment shows the location of any change in impedance in the line as well as the effect of any correction which may be attempted. This equipment requires interpretation of impedance reading to calculate the voltage standing wave ratio.
Another test heretofore employed was by a conventional slotted line with a single frequency applied at a desired level.
Wide departures in use from the applied frequency tended to render uncertain the results of such a test unless time consuming multiple points are also tested.
Sweep frequency methods are commonly used in production testing, wherein the voltage standing wave ratio or VSWR response of an entire band of frequencies is simultaneously depicted as an oscilloscope pattern. This permits observation of dynamic changes in the VSWR response due to mechanical changes or adjustments in cable or connector construction.
It is the principal object of the present invention to compensate for deviations by simple but effective procedures thereby to provide the best coaxial condition or linear capacity relation between the outer and inner conductors.
It is a further object of the present invention to improve the performance characteristics of coaxial cables in a simple but effective manner with a preliminary determination of the preferred locations for compensation and with a permanent correction applied at such locations.
It is a further object of the present invention to compensate coaxial cables by bringing the voltage standing wave ratio within predetermined limits and retaining the ratio within such limits.
a coaxial cable with well known type of end connections I attached thereto and with compensating elements applied thereto;
FIG. 3 is a transverse sectional view taken approximately on the line 3-3 of FIG. 2; and
FIG. 4 is a drawing of an oscilloscope pattern for a particular uncompensated coaxial cable and with the same cable compensated.
It should, of course be understood that the description and drawings herein are illustrative merely and that various modifications and changes can be made in the structure and methods herein set forth without departing from the spirit of the invention.
Like numerals refer to like parts throughout the several views.
In accordance with a preferred mode of practicing the invention the particular coaxial cable to be compensated has a resistance load applied to one end thereof. A sweep generator is coupled to a wave guide through a first transducer and calibrating means and connected to the cable, with a second transducer interposed between the wave guide and the cable. The wave guide has a directional coupler which picks up the combination of a reflected wave and a forward wave which is detected for observation on an oscilloscope.
Pressure is preliminarily applied to the cable by squeezing the cable around the circumference at locations spaced from the connectors and as determined visually on the oscilloscope for the best reduction of VSWR, and a permanent correction is preferably then applied at the selected locations.
The correction can be applied in any suitable manner to effect a permanent deformation at one or more selected locations, one suitable correction being provided by compressing and permanently deforming continuous bands or rings into engagement with the exterior of the cable.
Referring now more particularly to FIG. 1 of the drawings, a coaxial cable 10 having end connections 11 and 12 has a resistance load 13 connected thereto. The cable 10 may be of the type which includes an inner or central conductor 14 surrounded by an insulating and spacing layer 15 which in turn is surrounded by a conducting layer 16 with a surrounding insulating and protecting layer 17. The conducting layer 16 may be of single or double braided metallic strands, may be of metallic tubing, and may be of metal corrugated or spirally wound.
A sweep generator 20 of any suitable type is provided, having a sweep range determined by the ultimate use to be made of the cable 10. The range may be from megahertz (megacycles) to high gigahertz (gigacycles) of a level which the cable 10 can carry. As an example of a specific range, the frequencies may be from 4 to 12 gigacycles. The sweep generator 20 is connected through a filter or attenuating device 21 and through a transducer 22 to one end of a wave guide 23 to which, at the opposite end, the cable 10 is connected through a transducer 24.
The wave guide 23 preferably includes a directional coupler 25 which is connected in any suitable manner,
such as through a crystal detector 26 to an oscilloscope 27.
If the outer conducting layer 16 is of braided strands or otherwise lacks the capability of retaining a deformation applied thereto, the cable 10, before the attachment thereto of the end connectors 11 and 12 has a plurality of loose continuous rings or bands 30 slid thereon. The bands 30 are of copper, aluminum or any other material of adequate strength and capable of permanent deformation as hereinafter explained.
The manner of compensating a cable will now be pointed out.
With a cable 10 mounted as shown in FIG. 1, the sweep generator 10 is activated to apply the desired frequency range, say 4 to 8 gigacycles, 8 to 12 gigacycles or 4 to 12 gigacycles through the filter 21 and transducer 22, wave guide 23 and transducer 24 to the loaded cable 10.
The directional coupler 25 will pick up a combination of a reflected wave and a forward wave and the trace of this is available, after detection by the detector 26, for observation at the oscilloscope 27.
Referring now to FIG. 4, this figure represents the screen of the oscilloscope 27, with ordinates representative of the voltage standing wave ratio, and the abscissas repreabove it is preferred to correct first for the end of the sentative of the progression of the combination wave. The i curve 32, shown as a broken line, may be taken as a curve showing the condition of the cable 10 as manufactured and with the connectors 11 and 12 thereon. If an acceptable voltage standing wave ratio of the order of 1.2 be taken as the standard, it will be noted that the peaks of the curve 32 extend beyond that ratio value.
The compensation is effected by compressing the cable 10 at one or more locations with any desired implement, such as pliers, and observing the effect of the compressing as shown by the oscilloscope trace. The locations which tend to improve the ratio and flatten out curve 32 are determined by trial and error both as to the distance from the connectors 11 and 12 and as to the extent of this initial compression. The rings are preferably moved to the lengthwise locations on the cable 10 as indicated by the initial compressing and are then compressed by any suitable compressing or collapsing tool. As the compression of the rings 30 is being effected the trace on the oscilloscope 27 is observed and when the desired trace is obtained further compression of the rings 30 is terminated. The curve 33 shows a trace obtained for a particular cable 10 having an initial trace at 32, after compensation.
In determining the best locations of the squeeze points along the cable 10 an elfort is made to reduce all the high points but the locations giving the best reduction are preferably used.
The compression and permanent deformation of the rings 30 at locations to give improved characteristics of the cable 10, results in a capacitance change between the outer and inner conductors 16 and 14.
If the outer conducting layer 16 is a metallic tube, capable of taking and retaining a permanent set, the rings 30 will not ordinarily be required.
In making the compensating corrections as described cable having the worst condition but in testing a family of cables after the first few have been tested it will soon become apparent which end has the worst condition requiring correction.
It will thus be seen that simple but effective apparatus and methods have been provided for attaining the objects of the invention.
I claim:
1. The method of compensating a coaxial cable to an acceptable voltage standing wave ratio which comprises:
resistance loading the cable,
applying a predetermined frequency to the cable and determining the voltage standing wave ratio, and squeeze deforming at a selected location the outer conductor of the cable to change the capacitive relation thereof to the inner conductor and thereby reduce the voltage standing wave ratio.
2. The method as defined in claim 1 in which:
said deformation includes an initial trial deformation.
3. The method as defined in claim 2 in which:
an endless ring is applied to the cable before said frequency is applied, and
said ring is squeezed to provide a permanent squeeze deformation of said outer conductor.
4. The method of compensating a coaxial cable as defined in claim 1 which includes:
transferring the applied frequency through a wave guide having a directional coupler, and
detecting the voltage standing wave ratio and providing a trace of the ratio. 5. The method as defined in claim 1 in which: said deformation includes a permanent deformation, affecting the voltage standing wave ratio in one direction. 7
6. The method as defined in claim 1 in which:
said deformation includes an additional subsequent permanent deformation affecting the voltage standing wave ratio as determined upon reversal of the cable.
References Cited UNITED STATES PATENTS 2,516,528 7/1950 Purcell 29-600 X 3,158,825 11/1964- Vetter 333-83 3,287,672 11/1966 Heinz 333-83 3,349,479 10/1967 Sewell 29600 OTHER REFERENCES An Accurate Substitution Method of Measuring the VSWR of Coaxial Connections, A. E. Sanderson, The Microwave Journal, January 1962.
JOHN F. CAMPBELL, Primary Examiner.
D. C. REILEY, Assistant Examiner.
US. Cl. X.R. 29-600; 33396
US577919A 1966-09-08 1966-09-08 Compensation of coaxial cables Expired - Lifetime US3452429A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US57791966A 1966-09-08 1966-09-08

Publications (1)

Publication Number Publication Date
US3452429A true US3452429A (en) 1969-07-01

Family

ID=24310684

Family Applications (1)

Application Number Title Priority Date Filing Date
US577919A Expired - Lifetime US3452429A (en) 1966-09-08 1966-09-08 Compensation of coaxial cables

Country Status (1)

Country Link
US (1) US3452429A (en)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711942A (en) * 1968-01-04 1973-01-23 Amp Inc Coaxial connector controlled characteristic impedance process
US4161704A (en) * 1977-01-21 1979-07-17 Uniform Tubes, Inc. Coaxial cable and method of making the same
US4266207A (en) * 1979-11-07 1981-05-05 Uti Corporation Coaxial cable band-pass filter
US4296389A (en) * 1979-05-14 1981-10-20 Sanders Associates, Inc. Crimped coax reflective dispersive delay line
US4310816A (en) * 1979-05-14 1982-01-12 Sanders Associates, Inc. Dispersive delay lines
US4441781A (en) * 1982-08-17 1984-04-10 Amp Incorporated Phase-matched semirigid coaxial cable and method for terminating the same
US6366627B1 (en) 1983-09-28 2002-04-02 Bae Systems Information And Electronic Systems Integration, Inc. Compressive receiver with frequency expansion
US20110111709A1 (en) * 2009-11-06 2011-05-12 Ulun Karacaoglu Radio frequency filtering in coaxial cables within a computer system
US20110154656A1 (en) * 2009-11-06 2011-06-30 Harrison Joe A Systems and methods for manufacturing modified impedance coaxial cables

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2516528A (en) * 1944-03-21 1950-07-25 Edward M Purcell Wave guide coupler
US3158825A (en) * 1962-05-10 1964-11-24 Maurice J Vetter Movable resonant cavity tuning probe in dielectric sleeve having nonuniform outer surface
US3287672A (en) * 1964-11-19 1966-11-22 Marvin L Heinz Disc-loaded waveguide tuning machine which automatically tunes successive cavities by indenting waveguide wall
US3349479A (en) * 1965-02-11 1967-10-31 Dielectric Products Engineerin Method of manufacturing a coaxial electrical transmission line

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2516528A (en) * 1944-03-21 1950-07-25 Edward M Purcell Wave guide coupler
US3158825A (en) * 1962-05-10 1964-11-24 Maurice J Vetter Movable resonant cavity tuning probe in dielectric sleeve having nonuniform outer surface
US3287672A (en) * 1964-11-19 1966-11-22 Marvin L Heinz Disc-loaded waveguide tuning machine which automatically tunes successive cavities by indenting waveguide wall
US3349479A (en) * 1965-02-11 1967-10-31 Dielectric Products Engineerin Method of manufacturing a coaxial electrical transmission line

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3711942A (en) * 1968-01-04 1973-01-23 Amp Inc Coaxial connector controlled characteristic impedance process
US4161704A (en) * 1977-01-21 1979-07-17 Uniform Tubes, Inc. Coaxial cable and method of making the same
US4296389A (en) * 1979-05-14 1981-10-20 Sanders Associates, Inc. Crimped coax reflective dispersive delay line
US4310816A (en) * 1979-05-14 1982-01-12 Sanders Associates, Inc. Dispersive delay lines
US4266207A (en) * 1979-11-07 1981-05-05 Uti Corporation Coaxial cable band-pass filter
US4441781A (en) * 1982-08-17 1984-04-10 Amp Incorporated Phase-matched semirigid coaxial cable and method for terminating the same
US6366627B1 (en) 1983-09-28 2002-04-02 Bae Systems Information And Electronic Systems Integration, Inc. Compressive receiver with frequency expansion
US20110111709A1 (en) * 2009-11-06 2011-05-12 Ulun Karacaoglu Radio frequency filtering in coaxial cables within a computer system
US20110154656A1 (en) * 2009-11-06 2011-06-30 Harrison Joe A Systems and methods for manufacturing modified impedance coaxial cables
US8311503B2 (en) 2009-11-06 2012-11-13 Intel Corporation Radio frequency filtering in coaxial cables within a computer system

Similar Documents

Publication Publication Date Title
DE69026186T2 (en) Method for determining partial discharges in the insulation of an electrical power cable
US7642785B2 (en) Method and device for complex permittivity measurements as a function of frequency
US3452429A (en) Compensation of coaxial cables
US8653905B2 (en) High-voltage wideband pulse attenuator having attenuation value self-correction function
US20030115008A1 (en) Test fixture with adjustable pitch for network measurement
US4471294A (en) Electrical conduit defect location
JPH07198765A (en) Impedance meter
CN105891261A (en) Plating material passive intermodulation online testing device based on dual-mode transmission line structures
US4463309A (en) Method and device for determining the threshold of resistance of an electric or electromagnetic equipment to an external electromagnetic aggression
Lee et al. High frequency partial discharge measurement by capacitive sensor for underground power cable system
US2881389A (en) Measuring device for coaxial cables
CN106501617A (en) The calibration steps of dielectric material measuring piece, short-circuit calibrating device, dielectric material measuring method and device
JP3743225B2 (en) Transmission characteristic measuring probe and transmission characteristic measuring apparatus
Maher et al. High-frequency measurement of Q-factors of ceramic chip capacitors
Lee et al. Characteristics of high frequency partial discharge for artificially defected extra high voltage accessories
Martin et al. Shielding effectiveness of long cables
US2492150A (en) Electrical testing system
US3796949A (en) Slotted line with matched feed detector
DE102012024373B4 (en) Mode swirling chamber for testing electronic circuits
CN111122619B (en) Water content measuring system based on parallel spiral type telescopic time domain reflection probe
Zhong et al. A novel calibration method for PD measurements in power cables and joints using capacitive couplers
CN207798954U (en) A kind of bushing shell for transformer dielectric loss and capacitance test device
Caspers et al. Bench measurements of the LHC injection kicker low frequency impedance properties
Graham et al. The measurement and investigation of ionization level of rubber insulated cables
Selby et al. Coaxial radio frequency connectors and their electrical quality