US2195717A - Electrical high frequency signaling system - Google Patents

Electrical high frequency signaling system Download PDF

Info

Publication number
US2195717A
US2195717A US171826A US17182637A US2195717A US 2195717 A US2195717 A US 2195717A US 171826 A US171826 A US 171826A US 17182637 A US17182637 A US 17182637A US 2195717 A US2195717 A US 2195717A
Authority
US
United States
Prior art keywords
frequency
series
resistance
reactance
range
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
US171826A
Other languages
English (en)
Inventor
Cork Edward Cecil
Pawsey Joseph Lade
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.)
EMI Ltd
Electrical and Musical Industries Ltd
Original Assignee
EMI Ltd
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 EMI Ltd filed Critical EMI Ltd
Application granted granted Critical
Publication of US2195717A publication Critical patent/US2195717A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H7/00—Multiple-port networks comprising only passive electrical elements as network components
    • H03H7/38—Impedance-matching networks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P5/00—Coupling devices of the waveguide type
    • H01P5/02—Coupling devices of the waveguide type with invariable factor of coupling

Definitions

  • This invention relates to electrical high frequency systems and is particularly concerned with short wave transmitting and receiving systems and'equipment.
  • the present invention is also concerned with matching impedances which vary with frequencybut has particular reference to cases in which the variation in reactance is substantially linear and the resistance variation is symmetrically parabolic about a mean frequency.
  • the variation of resistance of an aerial over a range'of side-band frequencies is not-symmetrical about a'mean frequency, but a length of transmission line can be chosen such that when terminated by the aerial its input impedance has a series resistive component which is a maximum at'the mid-frequency and a reactive component which varies with frequency in a substantially linear manner, the reactance at the mid-frequency being not necessarily zero.
  • the deviation of resistance with frequency variation from the midfrequency is a parabola and in general a smoothly varying curve closely approximating to a parabola over a required'range of frequencies.
  • correcting reactive elements are provided which render the resistance of said apparatus substantially constant and equal to the resistance at the said frequency.
  • the reactive elements may be constituted by short lengths of transmission line.
  • allel tuned circuit having the correct ratio of inductance and capacity and tuned to frequency Q.
  • An inverse method may be employed for the compensation of "a resistance varying in the manner shown in Fig. .lb.
  • Fig. 2a shows diagrammatically the method of applying the invention.
  • Z represents the aerial impedance with series resistance varying in a parabolic manner as shown by the curve PQP in Fig. 2b and reactance varying linearly as shown by the line L in this figure.
  • the series circuit consisting of inductance ii and condenser 2 is added in series.
  • the series impedance at M has the same resistance/frequency curve as before, but the reactance/frequency curve is now modified to the .line M.
  • a'capacity is positive. This susceptanceis neutralized by the equal and opposite susceptance provided by the tuned circuit consisting of inductance 3 and-capacity 4 so that the impedance at M is a constant pure resistance equal to the original resistance at frequency Q.
  • Fig. 3a shows the equivalent parallel resistance'and'susceptance at Lof the-impedance Z and the modified values at M.
  • the susceptance at L is shown passing through but if this is not the case, the susceptance added at M must be such that the total susceptance at M is zero at the mid-frequency.
  • Fig. 3c shows the series values of resistance and reactance at the point M of Fig.3a'an'd the final value of impedance at N i. e. a constant pure resistance.
  • the reactance at M must pass through zero at the'frequency Q of the peak of the resistance-curve.
  • the reactance am at M must be given by If the reactance, at L is known, theamount to be contributed by'the series tuned circuit at these two frequencies is also known, and determines the values of inductance Land condenser 2 required.
  • the parallel tuned circuit .3, 4 must be tuned to the frequency Qand have a value of inductance capacity to neutralise thev equivalent parallel reactance of TP in series with :2? at the frequency P.
  • the invention may be applied to the compensation of variations of impedance in which the variation of reactance is linear whether or not it passes through zero at the peak of the resistance curve provided'that the rea'ctance at frequency P or P is not already greater than the required value and is in the same sense as the appropriate first tuned circuit. If the reactance at frequency P or P is in the correct sense but greater than that required, then the alternative method can be used.
  • Figs. 4 and 5 of the drawings show circuits utilising approximate quarter wavelength transmission lines to replace the lumped reactances shown in Figs. 2 and 3 in which short lines equal toquarter of a wavelength are employed. I I
  • lines of multiples of a quarter wavelength greater than one may be used.
  • an open circuited multiple half wavelength or a short circuited odd multiple quarter wavelength acts similarlyto a parallel tuned circuit and a short circuited multiple half wavelength or open circuited odd multiple quarter wavelength as a series tuned circuit.
  • the compensating arrangements described may usefully be combined with the property of transformation, and for this purposethe circuits 'of 'Figs. 2 and 3 for example may be modi fed so that the paralleltuned circuit is appropriately tapped to form an 'auto transformer.
  • a high frequency signaling system including apparatus the impedance of which isasubstantially pure resistance which varies'in an approximately parabolic'manner about a given frequency in the frequency range of signals fedto said apparatus, correcting reactive elements-of such magnitude and being so connected to said apparatus as to renderthe resistance of said apparatus substantially constant over said frequency range and equal to the resistance atthe said given frequency.
  • a high frequency signaling system according to claim 1 wherein said reactive elements comprise inductance and capacity connected in series with each other and in :series with said apparatus.
  • a high "frequency signaling system according to claim 1 wherein said reactive elements comprise inductance and capacity connected in parallel with each other and in parallel with said'apparatus.
  • a high frequency signaling system according to claim 3. wherein order to compensate for reactance due to correcting reactive elements connected in series with said apparatus "additional reactive elements are provided connected in parallel with said apparatus.
  • a high frequency signaling system according to claim 1 wherein in order to compensatefor I reactance due to correcting reactive elements connected to parallel with said appaartus, ad-
  • a shortwave transmitting system including which is such that the total reactance is zero at a selected frequency in said range and atfa side frequency the reactance is such that the equivalent parallel resistance is the same as at the selected frequency in said range.
  • a shortwave transmitting system wherein a parallel tuned circuit resonant at a selected frequency in said range, is
  • a shortwave transmitting system including an aerial connected by a feeder to transmitting apparatus wherein in order to render the resist ance of the said aerial constant over a range of frequencies a parallel resonant circuit is connected in parallel with said feeder, said resonant circuit including inductance and capacity the value of which is such that the total susceptance is zero at a selected frequency in said range and at a side frequency the susceptance is such that the equivalent parallel resistance is the same as at the selected frequency of said range.
  • a short wave transmitting system wherein a series tuned circuit resonant at a selected frequency in said'range is connected in the feeder in order to annul reactance due to said parallel resonant circuit.
  • a shortwave transmitting system wherein said series and parallel resonant circuits are constituted by a short circuited line a multiple of a quarter wavelength long including unity at the selected frequency in said range.
  • a shortwave transmitting system according to claim 7 wherein said series and parallel resonant circuits are constituted by open circuited lines a multiple of a quarter wavelength long including unity at the selected frequency in said range.
  • a high frequency signaling system includconnected together,and the series connected section having its output terminals open, the char- 'acteristic impedances of said line sections being ing apparatus the impedance of which'throughout a range about a given frequency is a substantially pure resistance having an extremum at said given frequency, leadsfrom said apparatus to a pair of terminals, a network between said terminals and said apparatus including a series circuit tuned to said given frequency connected in series with one of said leads and a parallel circuit tuned to said same given frequency in shunt'to said leads,
  • the tuning elements of said circuits being so chosen as to make the impedance between-said ,terminals at a second frequency in said range equal to a pure resistance of the same value as the resistance at the-given frequency.
  • An impedance network for presenting between a pair of terminals a substantially pure resistance over a range of frequencies, comprising a load circuit having resistance whose value passes through an extremum at a frequency within said range and a reactance network comprising series and shunt reactance elements connected respectively in series and shunt to said load with respect to said terminals, said series and shunt elements being so chosen as to make the impedance between said terminals at said extremum frequency and at two other frequencies in said range equal to said extremum of resistance.
  • An impedance network for presenting be tween a pair of terminals asubstantially pure resistance over a range of frequencies, comprising a load circuit having resistance whose value passes through an extremum at a frequency within said range and a reactance network comprising series and shunt reactance elements connected respectively in series and shunt to said load with respect to said terminals, said series and shunt elements being individually so chosen as to make the total reactance between said terminals vanish at the frequency of said extremum,
  • a load circuit having resistance whose value 1 passes through an extremum at a frequency within said range and a reactancenetwork comprising series and shunt reactance elements connected respectively in series and shunt to said load with respect to said terminals, said series and shunt elements being individually so chosen

Landscapes

  • Measurement Of Resistance Or Impedance (AREA)
  • Transmitters (AREA)
US171826A 1936-11-13 1937-10-30 Electrical high frequency signaling system Expired - Lifetime US2195717A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB31036/36A GB490449A (en) 1936-11-13 1936-11-13 Improvements in or relating to electrical high frequency signalling systems

Publications (1)

Publication Number Publication Date
US2195717A true US2195717A (en) 1940-04-02

Family

ID=10316973

Family Applications (1)

Application Number Title Priority Date Filing Date
US171826A Expired - Lifetime US2195717A (en) 1936-11-13 1937-10-30 Electrical high frequency signaling system

Country Status (5)

Country Link
US (1) US2195717A (fr)
BE (1) BE490449A (fr)
FR (1) FR829280A (fr)
GB (1) GB490449A (fr)
NL (1) NL149432C (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2428485A (en) * 1943-06-30 1947-10-07 Rca Corp Impedance matching device
US2434509A (en) * 1943-06-19 1948-01-13 Westinghouse Electric Corp Ultra high frequency conductor
US2446982A (en) * 1943-02-08 1948-08-10 Us Navy Apparatus for broad-band radio transmission
US2477635A (en) * 1944-11-25 1949-08-02 Standard Telephones Cables Ltd High-frequency switch
US2541836A (en) * 1943-03-11 1951-02-13 Winfield W Salisbury Inner conductor joint for coaxial lines
US2593474A (en) * 1944-10-03 1952-04-22 Us Sec War Antenna matching section
US2677808A (en) * 1946-04-11 1954-05-04 Us Navy Power monitor
US2743422A (en) * 1952-02-20 1956-04-24 Sperry Rand Corp Coaxial stub supports

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE752924C (de) * 1939-04-04 1953-02-23 Telefunken Gmbh Breitbandantenne
DE969386C (de) * 1941-01-01 1958-05-29 Pintsch Bamag Ag Frequenzabhaengiger Blindwiderstand fuer ultrakurze Wellen

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2446982A (en) * 1943-02-08 1948-08-10 Us Navy Apparatus for broad-band radio transmission
US2541836A (en) * 1943-03-11 1951-02-13 Winfield W Salisbury Inner conductor joint for coaxial lines
US2434509A (en) * 1943-06-19 1948-01-13 Westinghouse Electric Corp Ultra high frequency conductor
US2428485A (en) * 1943-06-30 1947-10-07 Rca Corp Impedance matching device
US2593474A (en) * 1944-10-03 1952-04-22 Us Sec War Antenna matching section
US2477635A (en) * 1944-11-25 1949-08-02 Standard Telephones Cables Ltd High-frequency switch
US2677808A (en) * 1946-04-11 1954-05-04 Us Navy Power monitor
US2743422A (en) * 1952-02-20 1956-04-24 Sperry Rand Corp Coaxial stub supports

Also Published As

Publication number Publication date
BE490449A (fr)
NL149432C (fr)
GB490449A (en) 1938-08-15
FR829280A (fr) 1938-06-17

Similar Documents

Publication Publication Date Title
US2270416A (en) Electrical wave system
US2195717A (en) Electrical high frequency signaling system
US2184771A (en) Antenna coupling means
US1907965A (en) Automatic tuning
US2188389A (en) Electrical high frequency signaling system
US2216964A (en) Coupling system
US2125127A (en) Electric phase controlling circuit
US1719052A (en) Single-side-band carrier system
US3049682A (en) Constant bandwidth coupling system
GB1141087A (en) Electrical apparatus exhibiting a substantially constant tunable bandwidth
US2503739A (en) Circuit arrangement producing a phase displacement having a substantially constant value
US3464015A (en) Network for matching an aerial to a radio transmitter
US2541650A (en) Wave length modulation
US1962910A (en) Coupling system
US1835080A (en) Transmission regulation in cable circuits
Sterling et al. The radio manual
US1890034A (en) Electrical coupling system
US2390839A (en) Radio frequency coupling network
US1866456A (en) Coupling device
US2357442A (en) Radio receiver
US1898180A (en) Coupling arrangement
US1725721A (en) Method and means for combining frequencies
US2971161A (en) I.f amplifier with electronically controllable band-pass
US2538544A (en) Hyperfrequency wide-band impedance matching network
US2082587A (en) High-frequency circuit