US2002192A - Electrical circuit arrangement - Google Patents

Electrical circuit arrangement Download PDF

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Publication number
US2002192A
US2002192A US581930A US58193031A US2002192A US 2002192 A US2002192 A US 2002192A US 581930 A US581930 A US 581930A US 58193031 A US58193031 A US 58193031A US 2002192 A US2002192 A US 2002192A
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United States
Prior art keywords
resistance
circuit
network
correction
inductance
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Expired - Lifetime
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US581930A
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English (en)
Inventor
Rust Noel Meyer
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RCA Corp
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RCA Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/04—Control of transmission; Equalising
    • H04B3/14—Control of transmission; Equalising characterised by the equalising network used
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/04—Control of transmission; Equalising
    • H04B3/14—Control of transmission; Equalising characterised by the equalising network used
    • H04B3/143—Control of transmission; Equalising characterised by the equalising network used using amplitude-frequency equalisers
    • H04B3/145—Control of transmission; Equalising characterised by the equalising network used using amplitude-frequency equalisers variable equalisers

Definitions

  • FIGS. 9 and 10 are vector diagrams showing cuit arrangement of substantially constant imthe principal vectors for the complex network of pedance, which is adapted to be employed for v Figure 8.
  • Figure 11 illustrates a simplified comfrequency correction purposes.
  • plex network diagram of a circuit arrangement 5 It is, of course, well known that the impedsuch as is shown in Figure 8.
  • Figure 12 illustrates ance offered by a parallel circuit consisting of in- .a further circuit scheme embodyingthe princiductance, resistance and capacity or by a comples of the present invention.
  • Figure 13 is a bination of such circuits is over-all non-reacvector diagram illustrating the effect of varying l0 tive (i. e. of zero total-reactance though having the circuit characteristics of Figure 12.
  • Figure reactance in the component elements and is 14 illustrates a phase correction circuit arequivalent to that of the ohmic resistance if the rangement embodying the principles of this ininductance, capacity and resistance are so provention. portioned that the last quantity. is equal to the Referring to Figure 1 which shows one way of 15 square root of the quotient of thecapacity into carrying out the inventioma correction circuit 15' the inductance.
  • a circuit consistcomprises a network consisting of two parallel ing of two parallel branches, the one comprising branches, the'one comprising an inductance! and inductance and resistance in series, andthe other, aresistance r in series, and the other a capacity-c I capacity and resistance in series, offers for all and aresistance r in. series.
  • Means are provided frequencies a substantially constant impedance for tapping off the, voltageset up across the re- 20 equal to that of, a pure resistance of lu equal sistance portions in the two. parallel branches.
  • the Other p ypa g-S rly 30 circuit of this kind to provide voltages suitable cenhected across the resistance in t e other for use for freq'uency'correction purposes.
  • branch of t e eilcuit- Preferably a reversing Acc rding to thi invention a frequency.
  • switch S is included in the circuit of one primary re ti n ir it, comprises a, b t ti ll 'so that the'sense of combination of the voltage stant impedance over-all non-reactive network, Set D in the tWO primaries y be sed W en 35 means fo tapping. 1 lt s t up a o desired.
  • the resistance-inductance-capacity i t nc i th ind tive d min capacity network is so proportioned that each resistance branchesof said network, and means for combinis equal to the Square feet of the q ot e t ing Said voltages t give gmt m; Voltage of the capacity into the inductance.
  • Figure 6 is a vector Preferably. the tapping points upon the diagram chart of the circle type illustrating cirbranches of the network are movable as indi- Figures 6A and 6B.
  • Figure 7 illustrates agroup the reversing switch S is in the position giving of curves which may be used toassist in the deconstantamplitude and no phase change, if. the sign of a correction circuit for any particular case.
  • tapping point in the capacity branch of the cir- Figure 8 is a complex network diagram wherein cuit be moved down the resistance r in that branched sub-networks are shown substituted for branch (i.ge., towards the junction point of. the
  • the effect will be to produce a response characteristic dropping in amplitude as the frequency is raised. If, on the other hand, this tapping point be kept stationary, and the other tapping point be varied the reverse effect i. e. a rising characteristic, will be produced, the amount of tilt produced being governed by the position of the tapping pointson the resistances.
  • the frequency at which correction begins to be obtained depends on the relative values of the inductive reactance and of the capacity reactance to the resistance. From this it follows that if a correction is required on low frequencies (e. g. for low notes) large values of inductance and capacity are required, whilst if a correction operative on higher frequencies (e. g. corresponding to high notes) is'required, smaller values of inductance and capacity must bechosen,
  • phase corrections may be obtained; or 'a combination of phase and amplitudecorrections may be obtained.
  • transformer for combining the voltage tapped off from the two resistances.
  • the transformer may be dispensed with and the circuit of Figure 2 adopted,
  • FIG. 3 shows a. further form of circuit which-may be adopted in the case of amplitude correction.
  • the "impedance of the circuit receiving the correcting voltages and connected at II should of course be of relativelyihigh impedance compared to the resistances r r
  • many more complicated forms of substantially constant impedance overal l-non-reacti ve "networks may be employed.
  • such a network maybe as shown in Figure '4 and may comprise two parallel branches, one consisting of a' first inductance Z in series with a second inductance and capacity c the last mentioned two reactances being each shun-ted by a resistance 1 or r and the other consisting of a capacity c 'a second-capacity c and an inductance Z allfin series, the last mentioned two reactances "being each shunted by a resistance r or'r
  • the network comprises two parallel circuits in series, the first parallel consisting of a capacity 0 shunted by a resistance r and a capacity c in series,
  • any of the resistances'included in any of the illustrated arrangements may be replaced by a branched sub-network and any of the resistances in the branched sub-networks may themselves be-replaced by further branched subnetworks and so on to any desired degree of complexity, the substituted branched sub-networks being, of course, themselves networks in accordance with this invention. It is not necessary that all the component branched networks making up a composition network should be all designed to halve the same quadrantal frequency and it may be desirable in many cases to design the various networks to have difierent quadrantal frequencies.
  • the combining transformer or other device (if any) employed to combine the voltages set up in the branches of the substantially non-reactive network should of course be so arranged that substantially no load is thrown back into the network,'for, if any appreciable load be thrown back,
  • the attenuation curve of the circuit to be corrected is plotted out on: the same logarithmic paperas the curves of Figure '7 and to the same scale in decibels attenuation but with attenuation values rising upwards from a zero line at the bottom of the paper instead of downwards from a zero at the top.
  • the logarithmic paper employed is transparent, and the curve to be corrected for is moved over the curves of Figure 7 until it is superimposed upon that curve of Fig ure 7 which is found to be nearest to the curve to be corrected'for.
  • the percentage correction is noted, and from the relative position of the frequency lines on thetwo sets of curves the required quadrantal frequency is immediately determinable. For'example, if it were found that the attenuation curve of Figure 7 nearest to the curve forwhich correction was required was the Z L C As however that 1 L and C are directly determinable.
  • Figures 9 and 10 are vector diagrams of the same basic type as that of Figure 6 but showing only the principal vectors for the complex network of Figure 8.
  • the diagrams of Figures 9 and 10 are constructedon the same principle as that of Figure 6 and are obvious developments thereof. ;'I'he number references in Figures 9 and 10 indicate the vectors representing the voltages set up between the correspondingly numbered points in Figure 8.
  • Figure 9 is a vector diagram drawn for the quadrantal frequency while Figure 10 is drawn for a frequency lower than the quadrantal frequency and such that the voltage across any particular inductance is one-half of that of the network (or sub-network as the case may be) of which it forms part.
  • the voltage-across vector 0-4 is the summation curve obtained by adding the 0% curve to itself, and as the same quadrantal frequency is used throughout this is equivalent to reading the 0% curve as though the attenuation scale had been doubled.
  • the voltage across vector 0-2 is obtainable by adding to the summation curve the original 0% curve, or in other words by reading the 0% curve as though 7 work the curves have to be added, since the one curve cannot be" read to difierent scales.
  • the inductance and condenser may be interchanged and it is also possible to combine networks and sub-networks in such a way as to multiply or add'in successive stages, one of the other percentage curves (20%, 4.0%, 60% and so forth).
  • correction circuits in accordance with this invention it is also possible to utilize the phenomena of resonance by designing one or more of the component networks of a circuit to be resonant within the range over which frequency correction is required.
  • A' correction circuit so designed maybe advantageously employed in many cases where it is desired'to correct for a frequency characteristic showing a change occurring within a relatively narrow range of frequenciesz-for example, it might be required to correct a transmitter whose frequency characteristic showed a drop of 4 or 5 decibels between 6,000 and 10,000 cycles per second.
  • An ordinary circuitcorrector of the simple resonant circuit type may, of course, be used for applying such a correction, but the present invention may also be adapted to give such a correction and offers the practical advantage that a circuit in accordance with the said invention is more readily calculable in its results and more flexible in its application than are simple resonant circuits.
  • the chart of Figure 7 can be employed for the estimation of correction curves by computing the values of oh; and cql q and from this knowledge the attenuation for any correction tapping can be found in terms of w and 01
  • a curve can then be plotted showing the relation between these frequencies and the actual applied frequencies to (below resonance) and m (above resonance). For example, suppose it is required to impart a lift up of 6 decibels between 5,000 and 10,000
  • a parallel branch type of circuit as shown in Figure 14 may be employed for phase correction and that by means of such I a circuit a 360 phase shift can be produced be- '1.
  • a parallel circuit having two branches, one ofsaid branches comprising a resistance and inductance and the other of said branches comprising a capacity and resistance, the resistances in both said branches being equal and also equal to I where L is theindfuctance and C the capacity of the circuit, an input circuit across said parallel circuit, having a source of electrical energy containing a band of frequencies connected thereto, means for tapping off resultant voltages set up across both said resistances at points which give an output amplitude which is a function of the input frequency, and an output circuit connected to said means.
  • a circuit for correcting for frequency distortion comprising a substantially constant imped ance overall non-reactive network having capacitance, resistanceand inductance elements so related as togive a constant pure resistance impedance between a pair of terminals to which input voltages of different frequencies are applied, means for tapping off Voltages set up across the resistance elements in said network, and means forfco nbining said voltages to give an output voltage which-is distorted in inverse senseto th input voltage.
  • a circuit for correcting for frequency distortion comprising a substantially constant impedance overall non-reactive network having capacitance, resistance and inductance elements so related as togive a constant pure resistance impedance between a pair of terminals to which input voltages are applied, means for tapping off voltages set up across the resistances of said network, and means for combining said voltages to give an output voltage for amplitude correction purposes including a switching element for changing at will the sense of combination of the tapped off voltages.
  • a circuit for correcting for frequency distortion comprising a substantially constant impedance overall non-reactive network to which input voltages are applied, said network comprising two series sections, one consisting of an inductance shunted by a resistance and the other of a capacity shunted by a resistance, each resistance being equal to the square root of the quotient of the capacity into the inductance, and
  • a circuit for correcting for frequency distortion comprising a substantially constant impedance overall non-reactive'network having capacitance, resistance and inductance elements so related as to give a constant pure resistance impedance between a pair of terminals to which input voltages are applied, means for tapping off voltages set up across the resistance elements in said network at points which give an output amplitude which isa function of the input frequency, and means for combining said voltages to give an output voltage for correction purposes in such fashion as to obtain. an output which varies with frequency, including. a transformer having two primary windings: one primary winding being in circuit with said inductance element and the other primary winding being in circuit with said capacitance element.
  • a circuit for correcting for frequency distortion comprising a substantially constant imment.
  • pedance overall non-reactive network to which input voltages are applied, said network comprising two parallel sections, one comprising an induc tance and a resistance in series and the other a capacity and a resistance in series, each resistance being equal to the square root of the quotient of the capacity into the inductance, and a double primary transformer connected to said sections for combining the voltages derived therefrom, one primary winding being across the resistance in the capacitance section and the other primary winding being across the resistance in the inductance section of said parallel arrange- 7.
  • a circuit for correcting for frequency distortion comprising a substantially constant impedance overall non-reactive network to which input voltages are applied, said network comprising two parallel sections-one comprising an inductance and a resistance in series and the other a' capacity and resistance in series,each resistance being equal to the square root of the quotient of the capacity into the inductancdand a double primary transformer connected'to said sections for combining the voltages derived therefrom, one primary winding being in circuit with the capacitance section and the other primary tion of said parallel arrangement, including a reversing switch connected to one primary winding whereby the sense of combination may be reversed at willi 8.
  • An equalizer circuit comprising a substantially constant impedance overall non-reactive network to which input voltages of different frequencies are applied, said network comprising a series branch including inductance and capacity in series, and a parallel branch including inductance and capacity in parallel, said branches being designed to be resonant at a frequency within a predetermined. range of applied frequencies, and means for combining the resultant voltages set up in said branches.
  • An equalizer circuit comprising a substantially constant impedance overall non-reactive network of two paths having capacitance, resistance, and inductance elements so related as to give a constant pure resistance impedance between a pair of terminals to which input voltages of different frequencies are applied, one of said paths including inductance and resistance, and the other of said paths including capacitance and resistance, the resistances in both of said paths being equal, and means for tapping oil" voltages set up across the resistances at points which are unsymmetrical with respect to the reactance elements.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Measurement Of Resistance Or Impedance (AREA)
US581930A 1930-12-24 1931-12-18 Electrical circuit arrangement Expired - Lifetime US2002192A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010087A (en) * 1958-11-14 1961-11-21 Bell Telephone Labor Inc Equalizer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2680231A (en) * 1950-01-07 1954-06-01 Gen Precision Lab Inc Tone control

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3010087A (en) * 1958-11-14 1961-11-21 Bell Telephone Labor Inc Equalizer

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