US2248793A - Method of regulating the amplitude of electric waves - Google Patents

Method of regulating the amplitude of electric waves Download PDF

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Publication number
US2248793A
US2248793A US273092A US27309239A US2248793A US 2248793 A US2248793 A US 2248793A US 273092 A US273092 A US 273092A US 27309239 A US27309239 A US 27309239A US 2248793 A US2248793 A US 2248793A
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Prior art keywords
amplitude
impulses
current
stimulus
valve
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Expired - Lifetime
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US273092A
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English (en)
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Terry Victor John
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International Standard Electric Corp
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International Standard Electric Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/02—Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation
    • H04L27/08—Amplitude regulation arrangements

Definitions

  • This invention relates to the regulation of the amplitude of electric impulses, particularly waves.
  • a regulating device for electric impulses accepts only incoming impulses of an amplitude greater than a certain value. which value increases and decreases with increase and decrease in the rate at which energy is being received from incoming impulses, and cuts down these accepted impulses so that their amplitude shall not exceed a fixed maximum.
  • a regulating device for electric impulses is characterized in that energy derived from a series of incoming impulses is stored in a storage means from which it is dissipated at a steady rate, and in that only incoming impulses of an amplitude above a value determined by the level of energy in the storage means are accepted, and
  • a device in accordance with this invention is capable of distinguishing between slow and rapid variations in the strength of the incoming impulses, being substantially unaffected by the former for a considerable range of amplitude.
  • a regulating device for electric impulses capable of distinguishing between slow and rapid variations in the amplitudes of a series of incoming impulses, characterized in that when a series of incoming impulses consists in a sinusoidal wave-train, the resultant output wavetrain contains substantially no even harmonic components and substantially no third harmonic component.
  • Fig. 1 shows one embodiment of the invention in which two stages of an amplifier are connected in series with an amplitude regulator
  • Fig. 2 shows a second embodiment of the invention in which the amplitude regulator is connected in shunt on the wires joining two stages of an amplifier
  • Fig. 3 shows various curves relating to the operation of the embodiments of the invention shown in Figs. 1 and 2; whilst Fig; 4 shows a similar set of curves for a much larger stimulus.
  • the circuits are designed to eliminate slow variations from the amplitude of an electric wave; but to accentuate rapid variations so that the wave will be reduced to zero amplitude by a sudden fall in strength of, say, half of the strength of the stimulus producing it. 7
  • the circuit is designed to respond more rapidly to increases in the strength of the stimulus than to corresponding decreases.
  • the circuits are also designed so that with most increases in. the value of the stimulus with which the circuit would have to deal the maximum amplitude of the wave is not even temporarily more than a third more than the steady value of the amplitude of the wave.
  • the wave to be regulated reaches the regulating means through an amplifying valve I and a transformer 2, the regulated output being applied to the control grid of a second amplifying valve H3.
  • the rectifying property of the grid of this second valve also takes part in the regulating process and an imaginary rectifier ll, externally connected and shown dotted in the drawings, brings about a regulating effect which corresponds to that produced by the grid of the valve.
  • the grid of the valve is shunted by a rectifier I2, which is in parallel with the imaginary rectifier I l but of opposite sense to it.
  • the regulating process is accomplished in two stages, which will be fully explained by reference to the description of the curves shown in Fig. 3.
  • the input terminals of the rectifier bridge are connected in series with a resistance I6 which is shunted by the primary winding of a transformer IT.
  • the resistance 9 in series with the secondary load of this transformer has a high value, so that the voltage across both primary and secondary of the transformer is approximately proportional to the current flowing through the input terminals of the bridge.
  • the voltage applied to the grid of valve I is also proportional to the current through the rectifier bridge, because although resistance 9 is high the resistancesof the rectifiers II and I2 which shunt thegrid are also very high, by reason of the potentials applied to them by grid batteries I8 and I9.
  • the secondary voltage of the transformer H exceeds the E. M. F. of battery I9 in a positive sense, current readily flows through rectifier I I preventing any appreciable further rise in the potential of the grid, and similarly the voltage which can be applied to the grid of III in a negative sense is limited by rectifier I2 and battery l8.
  • curve represents the stimulus producing the regulated wave, that is, it represents the efiective E. M. F. in the plate circuit of valve I, corrected for the ratio of transformer 2.
  • Line 32 represents the potential to which condenser I5 is changed by the rectified current when the stimulus has been constant long enough for a steady state to be reached. It is assumed that the capacity of condenser I5 is so large that no appreciable variation in potential takes place during a single cycle.
  • represents the current flowing through: the input i I I has no effect on the current flowing except in so far as it determines the potential 32,
  • also represents on a different scale, the secondary potential applied to the valve I0 through resistance 9 and I in consequence of the rectifiers II and I2, the potential applied to the grid of valve II], is limited to the form shown in curve 36, where E I8 and EI9 are the voltages of batteries I8 and I9.
  • Fig. 4 which is drawn to the same scale as Fi 3, represents a similar set of curves for a much larger stimulus.
  • curve represents the E. M. F. (corresponding to curve 30 in Fig. 3) and, the line 42 the new value of the potential VI 5 to which condenser I5 is charged.
  • the ratio of VI5 to the maximum value of the stimulus is determined chiefly by the relative proportions of the anode impedance of valve I (corrected for the ratio of transformer 2), the resistances of rectifiers 3, 4, 5 and 6 and resistances I3, I4 and I6. It is therefore the same in both figures. For this reason, current flows for the same proportion of a cycle in both figures and although the current represented by curve II is larger than that shown by curve 3
  • curve 46 assumes a rectangular wave shape, and the current impulses have a fixed length determined by the intersection of the curves 40 and 42.
  • the regulated wave form (36 or 46) contains no even harmonics when the stimulus is sinusoidal, and further, if VI 5 is made equal to one half the maximum value of this stimulus, the duration of each positive and negative current impulse is one third of a cycle, so that for large values of the stimulus giving a rectangular current impulse, the regulated wave form is free from the third harmonic also.
  • the fifth and higher harmonics are present, the former with an amplitude of one fifth that of the fundamental, but in practice the .wave being somewhat rounded diminishes this ratio and weakens the higher harmonics with the result that the regulated wave in spite of its appearance is fairly free from distortion components.
  • the circuit of Fig. 2 differs from that of Fig. 1 chiefly in that the voltage applied to the grid of valve III and resistance 9 is that produced across the input terminals of the rectifier bridge (instead of being proportional to the current through it) and the resistances I3 and I4 and condenser I5 are replaced by resistance 8 and inductance I.
  • ] and 40 again represent alternating E. M. F. in the anode circuit of valve I, but to another scale they also represent the current which would be obtained by short circuiting the secondary to transformer 2.
  • lines 32 and 42 represents the steady state value of current through the inductance l.
  • Curves 3t and 46 represent the voltage developed across the A. C. terminals of the rectifier bridge when the short circuit current (30 and ti exceeds the steady state current (32 and 42). Curves 36 and it show the voltage which is applied to the grid of valve ill after being limited by resistance 9, in combination with rectifiers H and I2.
  • circuits described provide a given degree of amplitude regulation with less intermodulation between the frequencies in the complex wave than is possible with other circuits possessing similar amplitude regulation characteristics.
  • a regulating device for electric impulses characterised by means for deriving energy from a series of incoming impulses, a storage means for storing said derived energy and dissipating it at a steady rate, means for accepting only incoming impulses of an amplitude above a value determined by the level of energy in the storage means, and amplitude limiting means for passing on said accepted impulses with an amplitude limited to a certain maximum.
  • a device characterised in that said storage device and said accepting means are so regulated that when a series of selected impulses consists in a sinusoidal wavetrain, the resultant output wave-train contains substantially no even harmonic components and substantially no third harmonic component.
  • a regulating device for electric impulses capable of distinguishing between slow and rapid variations in the amplitudes of a series of incoming alternating impulses, comprising thermionic valve apparatus, bias control means responsive to said variations for maintaining said apparatus biased to a point substantially one-half the peak Value of said incoming impulses, to avoid production of harmonics, for selecting said signal impulses according to amplitude variations, amplitude limiting means for said selected impulses for limiting the amplitude of both positive and negative peaks of said alternating impulses, and means for biasing said amplitude limiting means substantially identically for said positive and negative peaks to avoid the roduction of even order harmonics.
  • said bias control means comprising a rectifier bridge with its input terminals in series with one of the impulsetransmission lines and its output terminals connected by a leaky condenser.
  • said bias control means comprising a rectifier bridge with its input terminals shunting the impulse-transmission lines and its output terminals connected by an inductance.
  • a device further comprising impulse-transmission lines carrying impulses after their selection according to amplitude, "said amplitude limiting means comprising two rectifiers in parallel but of opposite sense connected in shunt to said line, the rectifiers allowing passage of a current only in response to an applied electromotive force in excess of a predetermined value.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Rectifiers (AREA)
  • Emergency Protection Circuit Devices (AREA)
US273092A 1938-05-21 1939-05-11 Method of regulating the amplitude of electric waves Expired - Lifetime US2248793A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB15179/38A GB517167A (en) 1938-05-21 1938-05-21 Improvements in and relating to methods of regulating the amplitude of electric waves

Publications (1)

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US2248793A true US2248793A (en) 1941-07-08

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US273092A Expired - Lifetime US2248793A (en) 1938-05-21 1939-05-11 Method of regulating the amplitude of electric waves

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US (1) US2248793A (de)
DE (1) DE890967C (de)
FR (1) FR854915A (de)
GB (1) GB517167A (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2561059A (en) * 1947-02-27 1951-07-17 Rca Corp Signal amplitude controlling transformer loading circuit
DE912711C (de) * 1941-12-13 1954-06-03 Philips Nv System zum UEbertragen von Telephoniesignalen mittels durch Impulse von gleichbleibender Dauer modulierter Traegerwellenschwingungen
US2775714A (en) * 1952-11-26 1956-12-25 Hughes Aircraft Co Variable impedance output circuit
US2822466A (en) * 1953-10-26 1958-02-04 Lighting & Transients Res Inst Apparatus for reducing radio interference
US2956158A (en) * 1957-04-23 1960-10-11 Sperry Rand Corp Voltage discriminating circuit
US3047746A (en) * 1959-12-08 1962-07-31 Bell Telephone Labor Inc Surge suppression for power supplies
US3584920A (en) * 1969-05-20 1971-06-15 Us Army Sampling device
US3771063A (en) * 1972-03-13 1973-11-06 Calnor El Paso Inc Bi-polar phase detector

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE912711C (de) * 1941-12-13 1954-06-03 Philips Nv System zum UEbertragen von Telephoniesignalen mittels durch Impulse von gleichbleibender Dauer modulierter Traegerwellenschwingungen
US2561059A (en) * 1947-02-27 1951-07-17 Rca Corp Signal amplitude controlling transformer loading circuit
US2775714A (en) * 1952-11-26 1956-12-25 Hughes Aircraft Co Variable impedance output circuit
US2822466A (en) * 1953-10-26 1958-02-04 Lighting & Transients Res Inst Apparatus for reducing radio interference
US2956158A (en) * 1957-04-23 1960-10-11 Sperry Rand Corp Voltage discriminating circuit
US3047746A (en) * 1959-12-08 1962-07-31 Bell Telephone Labor Inc Surge suppression for power supplies
US3584920A (en) * 1969-05-20 1971-06-15 Us Army Sampling device
US3771063A (en) * 1972-03-13 1973-11-06 Calnor El Paso Inc Bi-polar phase detector

Also Published As

Publication number Publication date
DE890967C (de) 1953-09-24
GB517167A (en) 1940-01-23
FR854915A (fr) 1940-04-27

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