US3265983A - Amplitude equalizer of speech sound waves - Google Patents

Description

Aug. 9, 1966 Filed Jan. 30, 1964 M. V. KALFAIAN AMPLITUDE EQUALIZER OF SPEECH SOUND WAVES 3 Sheets-Sheet 1 Rc NETWORK 4 z W2 /5 s in GAIN-CONTROUED PHASE $0l/RC AMPLIFIER DELAY 9 RC NE TWURK 6 8 K SPEECH GAIN-(Ol/TROHH; Ff/ASE Sol/RC5 ANPUf/ER nmy [I R6 NETWORK 4 Fig.2

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Aug. 9,1966 M. v. KALFAIAN AMPLITUDE EQUALIZER OF SPEECH SOUND WAVES Filed Jan. 30, 1904 2, Sheets-Sheet 2 IIVVENTOR.

United States Patent 3,265,983 AMPLETUDE EQUALIZER OF SPEECH SOUND WAVES Mcguer V. Kalfaian, 962 Hyperion Ave., Los Angeles, Calif. Filed Jan. 30, 1964, Ser. No. 341,240 3 Claims. (Cl. 330-123) This invention relates to automatic amplitude control systems, and more particularly to a system for normalizing the amplitude of propagated speech sound waves to a constant peak amplitude level. Its main object is to compress and expand the amplitude of propagated speech sound waves, so that wide variations of envelope peaks of ordinary speech sound waves may be reduced substant-ially to a constant peak amplitude without appreciable loss in voice quality. While the present invention is particularly contemplated for speech sound waves, however, its nature of amplitude equalization is also adaptable for other complex waveforms Where such normalization facilitates increase in intelligibility and wave analysis.

In various forms or" speech sound wave production and reproduction, it is often desired that the wide variations of envelope amplitudes in speech sound waves be compressed and expanded to a constant amplitude level. In one example, such amplitude equalization is desirable for transmitting speech sound waves through radio links where the signal-to-noise ratio is very low. In such noisy transmission, the phonetic sound a may be received intelligi'bly, because of its inherent high amplitude characteristics, but the phonetic sounds, such as, t, k, s, may be completely lost in noise, because of their inherent low amplitudes. In another form of speech sound wave reproduction, envelope-amplitude standardization is desirable for the analysis of amplitude ratios between various resonances in different phonetic sounds of the speech, for example, in a system as disclosed in my Patent No. 2,921,133 issued January 12, 1960; or other systems utilized for synthetic recognition of phonetic .sounds in spoken words. Since the term phoneticsound represents intelligibility, however, this sound may take other forms of intelligible characteristics, such as for example, the sound echo from a detectable target, or the various sound patterns made by lower forms of life, for example, by dolphins in their particular form of communication one with another. Thus the principal object of the present invention is to provide amplitude equalization without appreciable impairment of the original voice quality, at the same time increasing the intelligibility of the original vo1ce.

A wave-envelope in speech sound waves, as mentioned herein, is referred to a wave pattern having a major peaked wave and minor peaked waves. In a voiced vowel, these wave patterns are produced repeatedly by puffs of air from the glottis, which are set into vibrations in the momentarily formed resonant cavities of the vocal system. As each puff of air enters these cavities, an initial surge of pressure is formed, and accordingly, these vibrations are commenced by the high peaked Wave representing the major peak of said envelope. The peak amplitudes of these wave-envelopes, however, vary widely. For example, .an amplitude ratio of about thirty to one exists between the pronounced sound a and the sound s, even if the speaker tries to speak in monotone. Each one of these wave envelopes contains all the information necessary for conveying intelligence of the phonetic sound, as described by theory in my above-mentioned patent. Accordingly, it is not necessary for these major peaks to differ one from another for intelligible conveyance of phonetic sounds. In some previous literature it has been stated that these variations are necessary for smooth 3,265,983 Patented August 9, 1956 transition from one phonetic sound to another. But according to my analysis and tests, this smoothness at transition periods is effected by the gradual combination of resonances of both phonetic sounds (preceding and suc ceeding), rather than by the amplitude variations. Thus, a controlled constant level waveform of the original speech will have exactly the same quality of voice as the unmodified original; except of course, the former having higher intelligibility than the latter. Such high quality of voice reproduction can be obtained, however, only by stepwise modification of each successive envelope between major peaks without introducing distortion to the original wave. For example, as each initial surge of air starts in forming a wave pattern in the vocal tract, the amplitude of the entire wave pattern is predetermined with a definite waveshape. In conventional practice of amplitude equal zation, the gain of an amplifier is reduced by negative feed-back through a resistance-capacitance network. In this case, when the time constant of this network is adjusted to be substantially long, distortion to the original Waveform is negligible, and thereby effecting little impairment to the original quality of the voice; but complete amplitude equalization is not obtained. Where-as, when the time constant of the network is adjusted to be too short, the original waveform of each successive wave pattern is distorted due to high speed gain expansion of the amplifier, with consequential impairment of the voice quality.

Two types of wave distortions are effected by amplitude equalization: the first is peak clipping; and the second is destruction of the original amplitude ratios of the waves in a wave pattern one with respect to another. The first type of distortion adds upleasant noise to the voice, be-

sides changing the original characteristics of the voice. The second type just changes the characteristics of the voice, and intelligibility still remains high. I have disclosed in my patent application Serial No. 226,067, now abandoned, filed Sept. 5, 196-2 methods and means for equalizing the amplitude of speech sound waves with high quality voice reproduction. The system used, however, requires highly precise instrumentation, and while its performance is highly desirable for all purposes, simplicity is sometimes required where an array of such controlled amplifiers are to be used, for example, in telephone exchange installations, or in aircraft where space and power drain must be kept at a minimum. For such purposes, some loss in voice quality is not too objectionable, as the primary concern is high transmission of intelligence through low signal-to-noise conditions. Nevertheless, it is highly desirable that both positive and negative peaks of the speech sound waves are compressed to a constant minimum amplitude level, instead of only in singular direction, as most previously proposed systems provide.

Peak clipping in amplitude equalization is usually present in previously suggested systems, either due .to the particular system utilized, or due to instrumentation inetfficiency. This difiiculty is obviated in the presently proposed system by delaying the gain control teed-back, so that the original major peak of each successive wave pattern is produced in the output circuit before compression starts taking place. This delay can be degrees or less, as long as the original peak has been transmitted before control of the gain feed-back has started. I have found in my tests that when the major peak wave is in its down ward travel towards zero crossing, any sudden change in gain control of the amplifier will have no ill effect in the output voice quality, whatsoever. Thus by controlling the gain of the amplifier from major peak to major peak in delayed periods, the original sound wave can be amplitude equalized without peak clipping.

In speech communication over a carrier wave, it is desirable that the original amplitude variations of the sound waves are first normalized to a constant level, so that the maximum swing of carrier power may be modulated by the sound waves for maximum transmitter efiiciency, and high signal-to-noise ratio at the receiving end. The characteristic waveform of speech sound waves, however, is not symmetric in the positive and negative peaks, and gross-amplitude equalization, such as practiced in the previous art, will not satisfy the ultimate purpose. According to my tests, both negative and positive peaks of the sound wave can be equalized to a constant am plitude level without impairing the original quality :of the speaking voice, as long as other distortions do not occur. Accordingly, the present invention is contemplated principally to provide a gain suppression system without peak clipping, and which will provide suppression of both positive and negative wave peaks to constant amplitude levels. This will be more clearly explained in the following specification when considered in conjunction with the accompanying drawings, wherein:

FIG. 1 is a block diagram of a single ended amplitude equalizer, utilizing time shifted compression for avoiding peak clipping, in accordance with the invention.

FIG. 2 is a block diagram of a balanced amplitude equalizer for controlling both the positive and negative poled wave peaks of the original sound wave, in accordance with the invention.

FIG. 3 is a schematic arrangement of the balanced amplitude equalizer utilizing vacuum tubes as the gain controlling elements for sound compression, in accordance with the invention.

FIG. 4 is a schematic arrangement of the balanced amplitude equalizer utilizing photoconductor elements in balanced bridge circuits, for varying the impedances in one of their legs in accordance with projected optical light intensities upon them, as compression elements of the original sound level, in accordance with the invention.

From the foregoing brief it is apparent that various methods may be employed for amplitude equalization of the speech sound waves. The simplest method by which this can be accomplished is a direct feed-back after phase delay of the original signal. This is shown by a block diagram in FIG. 1, wherein speech signals in block 1 are applied to the gain controllable amplifier in block 2. The output signals from block 2 are phase delayed in block 3, and fed back in negative direction to reduce the gain of amplifier 2, in series with a resistance-capacitance network in block 4, and a limiting bias in block 5. The limiting bias in block 5 determines the amplitude level above which signal level suppression occurs. The preadjusted time constant of the RC network then determines the speed in which the amplitude variations of the speech sound wave is normalized. As described in the foregoing, the phase delay in block 3 prevents peak clipping, and therefore avoids harsh distortion of the original quality of the speaking voice. One objection of such a simple arrangement is that, it will not provide symmetric amplitude equalization of the asymmetric sound wave.

The block diagram in FIG. 2 is arranged for symmetric normalization of the speech sound waves, wherein, the output of speech source in block 6 drives the balanced gain controllable amplifier in block 7. The output of block 7 is applied to a balanced phase delay circuit in block 8, from which the signals are further applied to separate RC networks in blocks 9 and 10 for completing balanced feed-back loop to the amplifier 7. The limiting bias in block 11 can be common to both sides of the feedback loop. The output signals may be taken either from the output of amplifier in block 7, or from the output of phase delay circuit in block 8.

Up to this point the basic principles of balanced com pression of asymmetric sound waves has been described by way of the block diagram in FIG. 2. A practical circuit arrangement is shown in FIG. 3, wherein, the sound wave is generated in a balanced circuit, as represented by the block 12. The output of block 12 is applied in push pull mode to the first control grids of pentagrid vacuum tubes V1 and V2, and is amplified in the output transformer T1. The primary coils L1 and L2 of this trans former are split wound, so that they may be separately connected to the anode electrodes of V1 and V2, and to the plate supply voltage B1 in series with the resistors R1 and R2, respectively. With such an arrangement, the voltage waves developed across resistors R1 and R2 will be 180 degrees out of phase with respect to the input waves. Whereas, due to the reactive characteristics of the primary coils L1 and L2 the voltage wave will lead the current wave passing therethrough by degrees, and since audio transformers are not tuned within the range of audio spectrum, the voltage wave in the secondary coil L3 will be in phase with the primary coils L1 and L2. While available audio transformers will not yield this 90 degree phase relation within the entire audio spectrum in the arrangement given, there will exist sufiicient phase delay at all frequencies to satisfy the required performance, since, the required phase delay is up to the point where the original wave peak has already passed through the amplifier. The voltage waves developed across the secondary coil L3 are then rectified by the diodes D1 and D2, and charged across the capacitors C1 and C2, the common return connections of which are terminated to the center tap of coil L3 in series with the limiting bias supply B2. The voltage value of bias B2 is adjusted to the minimum level at which the sound amplitude is desired to pass the transformer T1. Any sound wave above this adjusted level causes conduction of the diode D1 or D2, which in turn allows its associate capacitor C1 or C2 to charge. The capacitors C1 and C2 are charged in negative polarity, and directly connected to the secondcontrol grids of tubes V1 and V2, respectively, so that any negative voltage across these capacitors causes proportional gain reduction of the respective tubes. Thus with sufiicient gain provided by the amplifier, a wide range of peak amplitude variations of the original sound waves in block 12 may be compressed to a constant level across the secondary coil L3 of transformer T1. The discharge of capacitors C1 and C2 is effected by the parallel connected resistors R3 and R4, respectively, which effect constant expansion of the amplifier gain. Thus at each high peaked wave in either positive or negative polarity, the capacitor C1 or C2 charges in negative polarity for reducing the gain of the amplifier. At the same time, however, the gain of the amplifier increases at a constant time rate during minor peaks of the sound wave, due to the constant discharge of these capacitors by the parallel connected resistors R3 and R4. The time constants of these capacitanceresistance networks determine the speed in which said gain expansion of the amplifier occurs. As described in the foregoing, when such expansion of the amplifier gain occurs at high speed, the original waveform of the sound is distorted, and thereby causing distortion of the original voice quality. As stated, however, such wave distortion is not as serious as by wave clipping, and since wave clipping is avoided by delay action of sound compression, the voice quality is affected only slightly for practical use.

The schematic arrangement of FIG. 3 is shown with one stage of amplitude equalization. When the amplitude of input sound wave from block 12 experiences extreme variation, however, the dynamic characteristics of vacuum tubes V1 and V2 may not satisfy the required normalization with a single stage, and more than one stage of equalization may be necessary. Thus the first stage may be repeated, as required. With multiple such stages, it is preferable that each succeeding stage is driven with inphase sound waves. For this reason, the output signal to the succeeding stage of sound compression is taken from the in-phase signals across resistors R1 and R2 by way of the coupling capacitors C3-and C4, which are further connected to the primary coil L4 of transformer T2. The output signal may then be taken from the secondary coil L5 of this transformer. Due to the delayed action of sound compression, it will be noted that when the sound amplitude is rising the first sound Wave peak will pass through the amplifier without any compression. Similarly, when the sound amplitude is receding the last sound wave peak will pass without any compression. In normal speech, however, the increase or decrease in amplitude of the sound wave is gradual, and since said first and last peaks constitute only a small portion of the sound wave, they may be allowed to pass, or clipped, without being noticeable in the sound output.

In the schematic arrangement of FIG. 3, the gain controlled .amplifier has been shown utilizing variable-mu vacuum tubes. Transistors (for example, tetrodes) may be substituted to obtain equivalent performance of sound normalization. However, these devices, especially transistors, are susceptible to distortion when operated within wide range of amplitude variations, and therefore, require more than one stage of amplitude equalization for the desired degree of sound compression. Instead of utilizing these variable-mu devices, however, it is possible to vary the resistance in one leg of a bridge circuit against any range of signal amplitude variation without causing distortion of any kind, whatsoever. For fast control of resistance value, the resistive element in this. leg may be substituted by a photoconductor, so that its resistance may be changed at will by an optical light, such as produced by a filamentary bulb, or by a solid state device, for example the electroluminescence emitted from the gallium-arsenide mesa diode. Since photoconductors possess extremely high resistance (for example, 800 megohms) in dark states, and low resistance in lighted states (for example, 4000 ohms) a single-stage of amplitude compression may be found satisfactory for any purpose without encountering undesired nonlinear characteristics. A schematic arrangement utilizing light-modulated variable resistors in bridge circuits are, accordingly, shown in FIG. 4.

In FIG. 4 the input sound signal is applied to the primary coil L6 of transformer T3. The secondary is split into two separate coils L7 and L8. Across the coil L7 are series-connected two resistors R5 and R6 of equal values, and their junction point connected common to ground. From the upper terminal of coil L7, there is connected a resistor R7, and in series with it connected a photoconductor device PC-l. From the lower terminal of coil L7, there is connected a resistor R8, and thereon to the photoconductor PC-l. Thus, when the total resistance of R7 in series with the resistance of PC-l is equal to the resistance of R8, the voltage between the junction point of resistors R5, R6, and the junction point between R8 and,PC1 becomes zero at all times because of the balanced bridge arrangement. Whereas, when the resistance in one leg, for example, the resistance of R7 and PC-l is varied from zero to infinity, the signal across L7 appears across said two junction points from zero to maximum in reversed polarities. Thus assuming that the resistance of resistors R7 and R8 are of equal values, and assuming that the resistance of photoconductor PC-l in maximum lighted value is much lower than the value of R7, the output signal at junction point between R8 and photoconductor PC-1 will have a predetermined minimum amplitude during maximum lighted state of the photoconductor, and maximum signal amplitude during its dark state, since as stated, photoconductors usually have extremely. high dark resistance values. Accordingly, when the input signal amplitude across coil L7 is at minimum, the photoconductor PC-l may be left in dark state so that the signal is transmitted to the output terminal without suppression. Whereas when the input signal amplitude is at maximum, the photoconductor may be optically lighted at maximum, so as to reduce the signal at the output terminal. By varying the light upon the photoconductor according to the signal strength, the signal amplitude at the output terminal may then be held constant continually without the use of gain controllable amplifiers. For symmetric amplitude equalization, however, it is necessary that two such bridge modulating arrangements be used for both positive and negative peaks of the original sound wave. This second bridge may be obtained across the split secondary coil L8, to the two end terminals of which are coupled two series-connected resistors R9 and R10 of equal values, and the junction point between the two resistors connected to ground. To the lower terminal of coil L8 is connected a resistor R11, and in series with it connected a photoconductor PC-2. To the upper end terminal of coil L8 is connected a resistor R12 having equal resistance value as of R11, and the resistor R12 is connected to the PC-2 as a junction point for the output circuit from ground.

The output circuit terminal between the junction point of R8 and PC-l is coupled to the base electrode of amplifying transistor Q1 by way of coupling capacitor C5, and the output circuit terminal between the junction point of R12 and photoconductor PC-2 is coupled to the base electrode of amplifying transistor Q2 by way of coupling capacitor C6. A normal operating bias is applied upon the base electrode of transistor Q1 from across voltage dividing resistors R13 and R14 connected across the voltage supply B3. Similarly, a normal operating bias is applied upon the base electrode of transistor Q2 from across voltage dividing resistors R15 and R16 connected across the supply voltage B3. Thus the input signals from the two bridge modulating circuits are amplified separately by the amplifying transistors Q1 and 32 in their collector circuits which are connected to the center tapped primary coil L9 of transformer T4. The balanced signal voltages developed across the secondary coil L10 of transformer T4 are separately rectified through diodes D3 and D4, for storing these voltages across capacitors C7 and C8. These stored voltages are applied in forward direction to the base electrodes of transistors Q3 and Q4, in series with the current limiting resistors R17 and R18, respectively, so that these transistors can vary the magnitude of current flowing through the filaments of their respective light bulbs LB-l and LB-Z. According to the current variations through the filaments of these light bulbs their light intensities vary for varying the resistances of photoconductors PC1 and PC-2; thus establishing the required suppression of the original sound. The output may then be taken from the secondary coil L11, or in any mode as found suitable. It must be mentioned at this point that photoconductors are not the only devices for displaying variable resistance characteristics, as thermistors or varistors, such as the field effect resistor, also display variable resistance characteristics, and could be used instead of the former. In reference to the arrangement of FIG. 3, it will be noted that the parallel connected resistors R3, R4 across storage capacitors C1, C2 are omitted in the arrangement of FIG. 4. In this case, however, the base-emitter resistance paths of transistors are usually low, and will provide the necessary load impedances across C7 and C8 for their discharges. Thus by choosing the proper values for storage capacitors C7 and C8 with regard to the base-emitter resistances of the selected transistors for Q3 and Q4, the required charge and discharge time constants may be predetermined. In this zarrangement, the limiting bias (B2 in FIG. 3) is also omitted, since first, the conductance of diodes D7 and D8 usually start at some value above zero voltage, and second, the emitter to collector conductance of higher powered transistors (necessary for driving the light bulbs) also start by forward bias upon their base electrodes at some value above zero voltage; thus these operating gaps providing the necessary limiting action.

In reference to the foregoing, it has been stated that the positive and negative peaks of the speech sound waves are not always symmetric. Thus in each branch of the bridge circuits across secondary coils L7 and L8 of transformer T3 in FIG. 4 the original sound wave is amplitude equalized separately. This does not mean, however, that rectified action takes place, since variation of the resistance in either photoconductor PC-l or PC-Z results in amplitude variation of the sound wave in both positive and negative polarities simultaneously. The sound wave in both bridges are combined in the output transformer T4, and due to the mutual inductance between both legs of the balanced transformer, the equalized .amplitudes of both positive and negative polarities of the sound wave are averaged out, so that disproportionate amplitude equalization of appreciable magnitude does not appear in the final output wave. As described in the foregoing, however, some disproportionate amplitude equalization in the positive and negative polarities of the speech sound wave does not affect the original quality of the voice. With the preferred embodiments of the invention thus given, it becomes apparent that various other modifications, substitutions of parts, and adaptations may be made without departing from the true spirit and scope of the invention.

What I claim is:

1. An arrangement for symmetric amplitude control of complex waves having asymmetric oppositely poled peaks, without peak wave distortion, the arrangement comprising a push-pull amplifier having first and second bridge circuits inputs and an output; each of said first and second bridge circuits comprising a center tapped impedance means having two end terminals connected to the two end terminals of a series-connected variably-controllable resistive element and a fixed-value resistor, respectively, for forming said first and second bridge inputs by coupling the junction terminals between said fixedvalue and variably-controllable resistive elements of the said first and second impedance means to the said first and second inputs, respectively, from common parallel-connection of said center taps, means for generating said complex waves, and means for applying these waves in push-pull mode to said first and second impedance means, for amplifying said waves at the output of said amplifier; a phase shifting means connected to said output, the last said phase shifting means having first and second output-terminals; first and second unidirectionally energizable networks, each having a predetermined decaying but like time-constant; a reference amplitude level determining means for said first and second networks; first and second coupling means between said first and second output-terminals and said first and second networks, respectively, for energizing said networks in proportional magnitudes when the peak amplitudes of the phase shifted peaks of the amplified complex waves are above said reference level, at shifted time periods than the arrival of last said peaks at said output; means for translating said energization of the first and second networks into first and second controlling means; and means for varying said variably-controllable resistive elements of said first and second bridges by said first and second controlling means, respectively, for symmetrically compressing the admittance of the oppositely poled peaks of said generated complex waves to said output, and without distortion to the original waveshapes of said peaks by virtue of said phase shifted compression.

2. The arrangement as set forth in claim 1, wherein' each of said variably-controllable resistive-elements of the said first and second bridges comprises an electricalsensitive resistive-means, the required electrical energy of each of which is controlled by the said energization of said first and second networks, respectively.

3. The arrangement as set forth in claim 1, wherein each of said variably-controllable resistive-elements of said first and second bridges comprises .a photoconductor and a light-emitting device optically projecting thereupon; and means for energizing each of these light emitting devices in proportional magnitudes by the energization of said first and second networks, respectively.

References Cited by the Examiner UNITED STATES PATENTS 2,615,999 10/1952 Culicetto 330 X 2,663,002 12/1953 McManis et al. 330-445 X 2,958,047 10/1960 Kalfaian 330-144 3,185,936 5/1965 Fuller 33059 OTHER REFERENCES Koeblitz: Photocell in Feedback Circuit Regulates Output, Electronic Design, June 21, 1963, pp. 7677.

ROY LAKE, Primary Examiner.

R. P. KANANEN, N. KAUFMAN, Assistant Examiners.

Claims (1)

1. AN ARRANGEMENT FOR SYMMETRIC AMPLITUDE CONTROL OF COMPLEX WAVES HAVING A SYMMETRIC OPPOSITELY POLED PEALS, WITHOUT PEAK WAVE DISTORTION, THE ARRANGEMENT COMPRISING A PUSH-PULL AMPLIFIER HAVING FIRST AND SECOND BRIDGE CIRCUITS INPUTS AND AN OUTPUT; EACH OF SAID FIRST AND SECOND BRIDGE CIRCUITS COMPRISING A CENTER TAPPED IMPEDANCE MEANS HAVING TWO END TERMINALS CONNECTED TO THE TWO END TERMINALS OF A SERIES-CONNECTED VARIABLY-CONTROLLABLE RESISTIVE ELEMENT AND A FIXED-VALUE RESISTOR, RESPECTIVELY, FOR FORMING SAID FIRST AND SECOND BRIDGE INPUTS BY COUPLING THE JUNCTION TERMINALS BETWEEN SAID FIXEDVALUE AND VARIABLY-CONTROLLABLE RESISTIVE ELEMENTS OF THE SAID FIRST AND SECOND IMPEDANCE MEANS TO THE SAID FIRST AND SECOND INPUTS, RESPECTIVELY, FROM COMMON PARALLEL-CONNECTION OF SAID CENTER TAPS, MEANS FOR GENERATING SAID COMPLEX WAVES, AND MEANS FOR APPLYING THESE WAVES IN PUSH-PULL MODE TO SAID FIRST AND SECOND IMPEDANCE MEANS, FOR AMPLIFYING SAID WAVES AT THE OUTPUT OF SAID AMPLIFIER; A PHASE SHIFTING MEANS CONNECTED TO SAID OUTPUT, THE LAST SAID PHASE SHIFTING MEANS HAVING FIRST AND SECOND OUTPUT-TERMINALS; FIRST AND SECOND UNIDIRECTIONALLY ENERGIZABLE NETWORKS, EACH HAVING A PREDETERMINED DECAYING BUT LIKE TIME-CONSTANT; A REFERENCE AMPLITUDE LEVEL DETERMINING MEANS FOR SAID FIRST AND SECOND NETWORKS; FIRST AND SECOND COUPLING MEANS BETWEEN SAID FIRST AND SECOND OUTPUT-TERMINALS AND SAID FIRST AND SECOND NETWORKS, RESPECTIVELY, FOR ENERGIZING SAID NETWORKS IN PROPORTIONAL MAGNITUDES WHEN THE PEAK AMPLITUDES OF THE PHASE SHIFTED PEAKS OF THE AMPLIFIED COMPLEX WAVES ARE ABOVE SAID REFERENCE LEVEL, AT SHIFTED TIME PERIODS THAN THE ARRIVAL OF LAST SAID PEAKS AT SAID OUTPUT; MEANS FOR TRANSLATING SAID ENERGIZATION OF THE FIRST AND SECOND NETWORKS INTO FIRST AND SECOND CONTROLLING MEANS; AND MEANS FOR VARYING SAID VARIABLY-CONTROLLING RESISTIVE ELEMENTS OF SAID FIRST AND SECOND BRIDGES BY SAID FIRST AND SECOND CONTROLLING MEANS, RESPECTIVELY, FOR SYMMETRICALLY COMPRESSING THE ADMITTANCE OF THE OPPOSITELY POLED PEAKS OF SAID GENERATED COMPLEX WAVES TO SAID OUTPUT, AND WITHOUT DISTORTION TO THE ORIGINAL WAVESHAPES OF SAID PEAKS BY VIRTUE OF SAID PHASE SHIFTED COMPRESSION.

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