US2579338A

US2579338A - Superregenerative wave-signal translating system

Info

Publication number: US2579338A
Application number: US15244A
Authority: US
Inventors: Richman Donald
Original assignee: Hazeltine Research Inc
Current assignee: Hazeltine Research Inc
Priority date: 1948-03-16
Filing date: 1948-03-16
Publication date: 1951-12-18
Anticipated expiration: 1968-12-18
Also published as: BE487876A; FR982383A; DE840107C; CH275293A; GB659785A

Description

Dec. 18, 1951 Filed March 16, 1948 Conduciance Conduc1unce D. RICHMAN SUPERREGENERATIVE WAVE-SIGNAL TRANSLATING SYSTEM 3 Sheets-Sheet 1 DETECTOR Ampliiude AU DIO- FREQUENCY AMPLI FIE R Amplitu de f f f f Frequency- FIGZb Time FIG.4

INVENTOR. NALD RICHMAN ATTO RNEY Dec. 18, 1951 D. RICHMAN 2,579,338

SUPERREGENERATIVE WAVE-SIGNAL TRANSLATING SYSTEM Filed March 16, 1948 3 Sheets-Sheet 2 I26 FIG. 5

Conductance Amplitudes (In decibels) Fre qu en cy INVENTOR.

DONALD RICHMAN ATTORNEY Dec. l8, 1951 D. RICHMAN SUPERREGENERATIVE WAVE-SIGNAL TRANSLATING SYSTEM Filed March 16, 1948 3 Sheets-Sheet 3 I Io 25 26, 22 DSUPERREGENV AUDIO ERATIVE DETECTOR FREQUENCY AMPLIFIER AMPLIFIER :--o 9 o o v v 2i IIMM'WW 6) 11mm 5 i I 1 l l I VOHS INVENTOR. I DONALD RICHMAN J ATTORNEY Patented Dec. '18, 1951 SUPERREGENEBATIVE WAVE-SIGNAL TRAN SLATING SYSTEM Donald Richman, New York, N. Y., assignor to Hazeltine Research, Inc., Chicago, 111., a corporation of Illinois Application March 16, 1948, Serial No. 15,244

20 Claims.

The present invention relates to superregenerative wave-signal translating systems and is particularly directed to arrangements for improving the selectivity or frequency-response characteristic of such systems. While superregenerative arrangements of the type under consideration are subject to a variety of useful applications, they are especially suited for use as wavesignal receivers because of their inherent high sensitivity and, for convenience, the invention will be disclosed in that environment.

It is well understood that a superregenerative receiver comprises a regenerative oscillatory circult and some form of quenching arrangement. The latter constitutes aniintegral part of the regenerative circuit in the case of receivers of the self-quenching type or constitutes a separate signal source coupled to the regenerative circuit in the case of separately quenched receivers. In either form, the quenching arrangement controls the conductance of the regenerative circuit,

causing itto undergo repeating cycles in which the conductance has positive and negative values in alternate operating intervals. During any negative-conductance interval, the circuit exhibits an extraordinarily high gain and produces oscillations that are quenched or damped in the next succeeding interval of positive conductance. The oscillations which are thus periodically produced have a characteristic, such as an amplitude characteristic, which varies with the modulation of a received wave signal at the time the oscillations are initiated. These oscillations may thus be utilized in any of several well-recognized methods to derive the modulation components of the received signal.

The selectivity of the usual superregenerative receiver is analogous to that of several cascaded resonant circuits tuned to the oscillatory frequency of the regenerative circuit so long as the oscillations generated in any negative-conductwave signal in the following quench cycle.

fluence the response of the receiver to an applied It may be shown that such a receiver has a serrated selectivity characteristic with peak responses occurring at the oscillatory frequency of the regenerative circuit and at frequencies spaced therefrom by integral multiples of the quench frequency. Although the carry-over phenomenon just described does increase the selectivity of the receiver, it is inflexible and is able to af fect the selectivity characteristic only as a function of the quench frequency. Additionally, the modified selectivity can be attained only after several quench periods because the carry-over phenomenon inherently requires several quench cycles to manifest its effect.

Another prior receiver arrangement having somewhat improved selectivity is of the separately quenched type. It includes a quench-signal generator for applying to the regenerative circuit a quench signal of such wave shape that the conductance of the regenerative circuit is or more of the aforementioned limitations of ance interval are quenched'to an insignificant amplitude during the following positive-conductance period. For certain applications, it is highly desirable to provide for the receiver a substantially increased selectivity not realizable with the ordinary superregenerative receiver.

Some superregenerative receivers are known which have a selectivity sharper than usually encountered. For example, if the resonant-circuit damping during the positive-conductance intervals of a superregenerative receiver is insuflicient to suppress the oscillations of any quench cycle adequately, the oscillations carry over from one quench cycle to the next and inprior arrangements.

It is another object of the invention to provide a superregenerative wave-signal translating system having an improved arrangement for controlling the selectivity characteristic of the system.

It is a further object of the invention to provide a superregenerative wave-signal translating system having a selectivity characteristic which is shaped to include reduced-response serrations at predetermined desired frequencies.

It is another object of the invention to provide a superregenerative wave-signal translating system including improved means for eflecting variations of the regenerative circuit conductance to establish a selectivity characteristic exhibiting reduced-response serrations at particular frequencies.

A superregenerative wave-signal translating system, in accordance'with the present invention, comprises a regenerative oscillatory circuit having a predetermined oscillatory frequency. The system includes quench means coupled to the regenerative circuit for effecting a major cycle of conductance variation in the regenerative circuit to provide superregenerative amplification of the wave signal applied thereto, the major cycle having a portion representing a conductance change from a positive to a negative value. Additionally, there is provided a signalgenerating network so proportioned as to develop a periodic signal component which has a frequenc of the same order. of magnitude as the major conductance-variation cycle but which is substantially less than one-half the predetermined oscillatory frequency and which occurs in such time relation with-respect to the major cycle when applied to the regenerative circuit to efiect in at least the aforementioned portion of the major cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on the major .oycle. There is also provided coupling means for applying the periodic signal component to the regenerative circuit. Such a system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from the oscillatory frequency of the regenerative circuit and related to the occurrence of the minor conductance-variation cycle within the major cycle.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the drawings, Fig. l is a circuit diagram partially schematic of a complete superregenerative wave-signal receiver embodying the present invention; Figs. 2a, 2b, and 2c are curves utilized in explaining the operation of the receiver of Fig. 1; Fig. 3 represents a superregenerative receiver of the separately quenched type embodying a modified form of the invention; Fig. 4 is a curve indicating the wave form of the quench signal suitable for use in the receiver of Fig. 3; Fig. 5 represents a modified form of signal-generating system suitable for controlling the conductance of the superregenerator of Fig. 3 and Figs. 6a, 6b comprise curves used in explaining the operation when the modification is employed; Fig. 7 is a modified form of self-quenching superregenerative amplifier in accordance with the invention; Fig. 8 comprises curves utilized in explaining the operation of the arrangement of Fig. 7; and Fig. 9 is a. further modification of the invention as embodied in a superregenerative amplifier of the self-quenching type.

Referring now more particularly to Fig. 1, the arrangement there represented is a superregenerative wave-signal receiver of the self-quenching type operated in the logarithmic as distinguished from the linear mode. Linear-mode operation is characterized by the fact that the periodically generated oscillations are quenched before attaming saturation-level amplitude, whereas in logarithmic or saturation-level mode operation the quenching action takes place after the oscillations reach saturation-level amplitude. The receiver comprises a regenerative oscillatory circuit including a triode vacuum tube it] having the usual anode, cathode, and control electrodes. The oscillatory frequency of the regenerative circuit is predominantly determined by a resonant circuit comprising an inductor ii and condensers l2, l3, l4, and i5. The-resonant circuit may include a damping resistor l6 and its resonant frequency may be adjusted through the use of variable inductive or capacitive circuit components. As shown, the inductor Ii is adjustable for tuning purposes. The anode of tube It is conductively connected to the junction of inductor II and condenser i2. The control electrode is grounded through a condenser i1, thereby efiectively being connected to the side of the resonant circuit opposite that to which the anode is connected. The condenser I1 is shunted by a grid-circuit stabilizing resistor Ill. The cathode of the tube III is connected to ground through a signal-frequency choke coil I9 and is conductively connected to the junction of condensers l2 and [3 to complete the alternating-current paths of a Colpitts type of regenerative oscillatory circuit.

The quenching means conventionally included in the regenerative circuit of a self-quenching superregenerative receiver is provided by the condenser II and a resistor 20 which couples the condenser H to a source of unidirectional potential, indicated as +B. An inductor 2i is connected in shunt relation to the condenser l5 and is included with the resistor 20, the potential source +3, and the inductor II in an energizing circuit for the anode of the tube I ll. The inductor 2| and condenser l5 provide a signalgenerating network for periodically developing and applying to the regenerative circuit a periodic or alternating-current signal component for a purpose to be explained hereinafter. An antenna-ground system. 22, including an. inductor 23 inductively coupled to the inductor ll of the frequency-determining circuit, constitutes means for applying a received wave signal to the regenerative\ circuit for superregenerative amplification therein.

An inductor 24, inductively coupled with the inductor ll of the frequency-determining circuit ||-|6, is included in the receiver for deriving an output signal from the regenerative circuit. The inductor 24 is coupled to the input circuit of a conventional envelope or averaging detector 25 to the output circuit of which is coupled an audio-frequency amplifier 26 of any desired number of stages. A sound-signal reproducing device 21 is coupled to the output circuit of the audiofrequency amplifier 26 to utilize after amplification the modulation components derived by the detector 25.

Neglecting for the moment the signal-generating network provided by the condenser I5 and the inductor 2|, the described arrangement comprises a logarithmic-mode superregenerative receiver of the self-quenching type in which the self-quenching network I, 20 thereof is included in the anode circuit of the regenerator tube Hi. In operation, the condenser I4 is charged from the source +B through the resistor 20 and is discharged through the anode-cathode circuitof the tube [0. During the conductive intervals of the tube ill in which the condenser discharge takes place, the regenerative circuit generates oscillations at a frequency determined by the resonant circuit II-l6. Such oscillations are quenched in the following operating interval in which the tube I0 is nonconductive while the condenser i4 is recharged from the source +B. This provides conventional superregenerative amplification of a wave signal applied to the regenerative circuit from the antenna system 22, 23. The conductance of the regenerative circuit has positive values during operating intervals in which the tube I is nonconductive and the condenser is charging from the potential source +B. On the other hand, the circuit conductance has a negative value during intermediate operating intervals in which the tube I0 is conductive to discharge the condenser I4. The nominal quenching frequency, determined by the charging and discharging time constants of the condenser I4, is selected to have a value which is low relative to the oscillatory frequency of the regenerative circuit but preferably at least twice as high as the highest modulation frequency of the received wave signal. However, as is characteristic of a self-quenching superregenerator, the quenching frequency is not fixed during the reception of an amplitude-modulated signal but rather varies in accordance with the modulation components of the received signal. The variation in quench frequency is manifested in the recurrence rate of the generated oscillations which are supplied through the inductor 24 to the detector wherein the modulation components of the received signal are detected for further amplification in the audio-frequency amplifier 26. Thereafter, the modulation components are applied to the sound-signal reproducing device 21 for utilization in the usual manner. During operation of the receiver, the network l1, l8 stabilizes the quench frequency of the superregenerator.

The foregoing description neglected the function of the signal-generating network I 5, 2| and considered only the customary cycles of conductance variations established by the self-quenching network I4, 20. The self-quenching network develops a. repeating quench signal of approximately saw-tooth wave form and the resulting cycles of conductance variation are of essentially the same wave form. It may be demonstrated that the selectivity or frequency-response characteristic of the superregenerative receiver, when their influencing the oscillations developed in the next succeeding quench cycle, the selectivitycurve is smooth. The signal-generating network l5, 2| is included in the regenerative oscillatory circuit to be excited concurrently with the quenching network periodically to develop an alternating-current signal component for modifying the selectivity characteristic. Its action in accomplishing that result may be understood with reference to the idealized conductance-time characteristic of Fig. 2a.

The full-line portions of the curve of Fig. 2a may be considered to represent a major cycle of conductance variation of the regenerative cire cuit and, except for the specific wave form chosen for the graphical representation, may be deemed to be attributable to the self-quenching network I 4, 20. The circuit conductance during the interval t1-t2 has a very large positive value; during the interval t2-t4 it has zero value; and during the interval t4.--ts it has a very large negative value. This conductance variation may be thought of as repeating periodically to permit the alternate generation and suppression of oscillations in the regenerative circuit to accomplish superregenerative amplification of applied wave signals in the customary manner.

The broken-line curve of Fig. 2a represents what may be considered a minor cycle of conductance variation of the regenerative circuit, said to be minor because it occurs within and is of shorter duration than the first-described major cycle of conductance variation denoted by the full-line curve. This minor cycle, except for its specific wave form, illustrates the conductance variations of the regenerative circuit caused by the periodic signal generated in the

network

15, 21. It is clear from Fig. 2a that the minor cycle of conductance variation is superposed on the major cycle and establishes a negative value of conductance within the interval t2ta and a positive value of conductance within the succeeding interval ta-tr. At the time t: when the circuit conductance is entering upon the negative portion of the minor cycle, oscillations are initiated and increase in amplitude until they are damped starting at the time ta. Consequently, at the time t4 when the regenerative circuit has its principal" maximum sensitivity in the major cycle, that is, just as it enters into the negativeconductance interval of the major cycle, there are two signal components which may influence its response. The first is the received signal applied to the resonant circuit Il-l6 from the antenna 22. The second is in the nature of a transient signal resulting from the response of the regenerative circuit due to the minor cycle of conductance variation occurring in the interval til-1:4. The vector addition of these two si nal components determines the effective signal amplitude which establishes the initial amplitude of the oscillations initiated in the regenerative circuit at the time t4.

At time t4, the transient signal has an amplitude relative to the wave signal received by the antenna system 22 in accordance with the net value of conductance integrated over the minor cycle tat4. Expressed diiferently, the amplitude of the transient is determined by the difference between the shaded area A1, representing the integrated value of the negative conductance over the interval t2t3, and the area A2, denoting the integrated value of the positive conductance over the interval t:-t4. The amplitude and phase of the transient signal compared with that off-the applied amplitude-modulated wave signal govern the efiective amplitude of the resultant signal in the regenerative circuit at the time t4. Where the two signal components under consideration are in phase, the condition is equivalent to an increased amplitude of the received wave signal and, conversely, a condition in which they are out of phase is analogous to a decrease in amplitude of the received wave signal.

The transient signal has a fixed frequency corresponding to the oscillatory frequency of,the regenerative circuit as determined by the resonant circuit ll-l6 and it occurs, preferably, in a fixed time relation relative to the major conductance cycle. However, the oscillatory frequency of the transient signal compared with the frequency of the received wave signal is dependent upon the condition of tuning of the circuit ll-l6. For that reason, the phase relations of the transient signal and the received wave signal at the interval t4 of maximum sensitivity of the regenerative circuit vary as the circuit |l-|O is tuned over its response range. Therefore, the selectivity or frequency-response characteristic of the superregenerator may be of the type represented by the curve of Fig. 2b.

The'selectivity curve of Fig. 2b indicates a substantially uninterrupted frequency-response characteristic of the superregenerative receiver with a maximum response at the frequency I: corresponding to the oscillatory frequency of the regenerative'circuit. The characteristic has reduced-response serrations at frequencies {1, I2, is and f4 which are spaced from the oscillatory frequency f;- and related to the occurrence of the minor conductance cycle within the major conductance cycle. At each serration, the transient signal resulting from the influence of the minor cycle is 180 degrees out of phase with the received wave signal at the maximum sensitive intervals it of the regenerative circuit. Intermediate the serrations the response has minor peaks at frequencies for which the transient signal and the received wave signal are in phase at intervals of maximum sensitivity. The separation A! of the two minor peaks closest to the oscillatory frequency fr is approximately equal to the fre quency corresponding to the period ta-t4 of the minor conductance cycle. The separation between successive minor peaks on either side of the oscillatory frequency fr is also substantially equal to A). where the selectivity curve issym- .metrical about the oscillatory frequency, although a condition of symmetry need not necessarily be obtained as will be explained hereinafter. It should be understood that the minor peaks are present as a result'of theefiective modulation of the selectivity curve by the minor cycle. Therefore the separation of the minor peaks depends not only on the number of minor cycles present throughout the selectivity bandwidth and the constancy in frequency of the minor cycle but also on the relative slopes of the selectivity curve and the minor cycle. As the relative slopes vary with respect to each other from one minor cycle to the next, the separation will likewise vary. By proper control of the factors justdiscussed the separations may be equal as indicated in Fig. 2b.

Conductance variations of the type shown by the curves of Fig. 2a may be approximated with the circuit arrangement of Fig. 1. The selfquenching network I4, 20 develops a quench signal of substantially saw-tooth wave form for accomplishing the major cycle of conductance variation. The network l5, 2| develops an alternating-current signal in the form of a damped sinusoid to effect one minor cycle of conductance variation superposed on the major cycle. By suitably selecting the frequency of the network l5, 2| the resultant composite quench signal may have the wave form represented by the curve of Fig. 20.

In order that the selectivity characteristic may be uniform from one quench cycle to the next, it is preferable that the signal-generating network l5, 2| be synchronized with the self-quenching network I4, 20. This synchronization is inherently realized in the arrangement of Fig. 1 since the network |5, 2| receives a pulse of excitation each time the tube I becomes conductive under control of the network H, 20. It is sometimes advantageous to provide sufllcient damping in the network [5, 2| that the transient signal generated therein has a duration not appreciably longer than that of the major cycle of conductance variation. The damping may be provided by the inherent resistance of the inductor 2| or a separate damping resistor, not shown, may be connected in shunt relation to the inductor 2| to augment its inherent resistance.

In pra tical embodiments of the described receiver it it, desirable to select the resonant frequency of the network l5, 2| to be very much less than the oscillatory frequency of the regenerative circuit to obviate appreciable excitation of that network by the oscillations generated in the regenerative\circuit during its major negativeconductance intervals.

The resonant frequency of the network I5, 2| is also significant with regard to the continuity of the response characteristic of the superregenerative receiver in the frequency spectrum. When the resonant frequency has a, value of the same order of magnitude as the major conductance cycle, the superregenerator has a continuous or a substantially uninterrupted frequency-response characteristic. The expression substantially uninterrupted frequency-response characteristic" is used here and in the appended claims to mean a continuous range of response within a continuous frequency band even though the reduced-response serrations previously described may reduce the response to a very low value or to zero at one or more frequencies within that band. To realize an uninterrupted response, the resonant frequency of the network i5, 2| and the frequency of the periodic signal developed thereby to effect the minor conductance cycle may be of the same order of magnitude, that is, may be within a range from one and one-half to ten times the frequency of the major conductance cycle. Resonant frequencies of three to four times the principal quench frequency are useful in many applications of the present invention although it is not necessary to have an integral relation between the quench frequency and the resonant frequency of the network I5, 2|.

The parameters of the resonant circuit 5, 2| regulate the depth of the reduced-response serrations because they control the amplitude of the transient signal relative to the wave-signal amplitude, as modified by the frequency-response characteristic of the resonant circuit |l-l6 at the sensitive intervals t; of Fig. 20. Where these signals are of approximately equal amplitudes at any of the frequencies f1, f2, fa or Is, the serration at such frequency extends to about the abscissa axis in Fig. 2b, indicatingsubstantially zero response. Since the relative amplitudes and phase relations of the two signals may be controlled by appropriately selecting the parameters of the network l5, 2|, it is possible to adjust the depth and location of the reduced-response serrations to shape the selectivity characteristic in a desired manner.

In one embodiment of the Fig. 1 arrangement found to have practical utility, the following circuit constants were employed although they are not to be construed as limiting the application of the invention to the use of any particular circuit constants:

Tube l0, half section of a type 12AT7 Resistor l6, 6,800 ohms Resistor I8, 15,000 ohms Resistor 20, 10,000 ohms Condenser I2, 10 micromicrofarads Condenser I3, 10 micromicrofarads Condenser I4, micromicrofarads Condenser l5, 1,200 micromicrofarads Condenser ll, 3,000 micromicrofarads 9 Potential source +B, 250 volts Frequency of major conductance variations, 35

kilocycles Resonant frequency network I5, 2 I, 160 kilocycles' It will be apparent from the above description of the Fig. 1 arrangement that it is quite convenient to utilize the present invention in a selfquenching superregenerative received which includes in its regenerative system a network for developing periodicsignals to effect the minor cycles of conductance variation in synchronism with the major cycles of conductance variation. However, the invention is not limited to superregenerative receivers of the self-quenching type but may be utilized equally well inthose receivers where the quenching action is under the control of a signal-generating network that is external to or separate from the regenerative system. Such an embodiment is represented in Fig. 3 which in many respects is similar to that of I Fig. 1 and corresponding components thereof are designated by similar reference characters. The unit I may be any conventional superregenerative amplifier of the externally or separately quenched type including a quench-signal input circut for receiving a quench signal to efiect superregeneration. The quench-signal source of the present arrangement constitutes a signal-generating system including means for developing a first periodic signal component of saw-tooth wave form for effecting the usual major cycles of conductance variation in the superregenerative circuit. Unit 30 includes an additional network for generating a second and sinusoidal signal required to establish the aforementioned minor conductance cycles in the regenerative system. More specifically, the unit 30 comprises a blocking oscillator provided by a triode vacuum tube 3| and a resonant frequency-determining circuit. That resonant circuit comprises an inductor 32 which may be adjustable to facilitate a selective control of the period of the major cycles of conductance variations in amplifier Ill. The resonant circuit further includes

condensers

33, 34, 35 and 36 as well as a damping resistor 31. The cathode of the tube 3| is connected to ground through a signalfrequency choke coil 38 and is also connected to the junction of the

condensers

33 and 34. Its anode is directly connected to one terminal of the resonant circuit 32-31 and its control electrode is effectively connected to the opposite terminal thereof through a condenser 39. The control electrode is coupled through a stabilizing network, comprising series arm resistors 40 and 4| and a shunt-arm condenser 42, to a source of unidirectional potential indicated as +13. A source of space current +B is connected tothe anode electrode of the tube 3| through a decoupling resistor 43 and the inductor 32. An inductor 44 is connected in shunt relation to the condenser 35 to provide a network for developing a sinusoidal signal utilized to efiect minor cycles of conduct-- ance variation in the superregenerative amplifier Ill.

Neglecting for the moment the function of the network 35, 44, unit 30 is a conventional gridcircuit stabilized blocking oscillator which develops across the condenser 36 in the anodecathode circuit of the tube 3| a signal potential of saw-tooth wave form occurring at the blocktype represented by the curve of Fig. 4.

l0 ing frequency of the oscillator. The periodic pulses of anode-cathode current of the tube 3| excite the resonant circuit 35, 44 to develop a signal of damped sinusoidal wave form. The quenching signal applied byway of a coupling condenser 45 to the quench-signal'input circuit" of the'superregenerative amplifier Ill therefore has a repeating wave form which may be of the The quenching signal includes a component ofsawtooth wave form and a superposed damped sinusoid component. The saw-tooth component considered alone eifects the major cycles of conductance variation in the amplifier If to provide conventional superregenerative amplification of applied wave signals. The superposed sinusoid component has a frequency higher than, but of the same order of magnitude as, the saw-tooth the network 35, 44 is excited in a given time relation with each .pulse of anode-cathodecurrent of the tube 3| and thus in a given phase relation to the developed saw-tooth component. The si-. nusoid component effects additional minor cycles of conductance variation in the superregenerative amplifier Ill superposed on each major conductance cycle to impart reduced-response serrations to the selectivity characteristic of the superregenerative amplifier as explained in connection with the curve of 'Fig. 2b.

It is desirable that the-quench-signal output circuit of the blocking oscillator 30 beeoupled to the control electrode of the superregenerator vacuum tube included within the amplifier Ill because the circuit of the control electrode is in the nature of a low-current source. This avoids appreciableexcitation of the signal-generating network 35, 44 by-the oscillations periodically generated within unit III. The resonant frequency of the network 35, 44, as well as its damping, determines the number of minor cycles of conductance variation which the signal developed therein is able to superimpose on the major conductance cycles of the superregenerator III. The parameters of the network 35, 44 are selected to effect a selectivity characteristic with, reducedresponse serrations of controlled depth at desired frequencies within the frequency-response range of the superregenerative amplifier I0.

Fig. 5 represents a signal-generating network which may be substituted for the unit 30 to control the conductance of the superregenerative amplifier ID in the receiving arrangement of Fig. 3. The generating system of Fig. 5 is essentially a Hartley oscillator including-a triode vacuurn tube I20 and an associated resonant or frequency-determining circuit I2I, I22. One terminal of the resonant circuit is directly grounded and the other is connected to the control electrode of the tube I20 through a. grid condenser I23 and a leak resistor I24. The anode of the tube I20 is connected to a source of space current, indicated +B, through an integrating network provided by a condenser I25 and a resistor I26 and the cathode is connected to a tap on the inductor I2I. A condenser I2'I is the usual bypass for the space-current supply. Signal components developed in the resonant circuit I2 I, I22 and the integrating network I25, I26'are delivered to an output terminal I29 through a signalattenuating and phase-shifting network provided for adjusting the relative phase and magnitude of those components. The. attenuating and phase-shifting network includes a resistor I30 of large value and a small condenser I3I. One terminal of the resistor is connected to the high potential side of the resonant circuit I2I, I22 through a blocking condenser I32 the other terminal thereof being connected to the condenser I3I. The opposite terminal of the condenser I3I is connected to the high potential side of the integrating network I25, I26.

In the operation of the signal-generating system of Fig. 5, sinusoidal oscillations are generated in the resonant circuit I2I, I22 and these oscillations vary the potential of the control electrode I20 relative to ground. During intervals when the control electrode has its highest positive potential, pulses of anode-current flow in the anode-cathode circuit of the tube and are integrated by the network I25, I26 thereby to develop a signal of saw-tooth wave form. The attenuating and phase-shifting network I30. I3I permits the sinusoidal and saw-tooth signal components to be added together to provide a composite output signal at the terminal I29. This terminal may be connected with the controlelectrode circuit of the vacuum tube included in the superregenerative amplifier I. Where such a connection has been established, the conductance of the superregenerative amplifier is varied under the control of the composite signal and preferably follows the patterns of Fig. 6a.

In that figure, curve C represents a major cycle of conductance variation of saw-tooth wave form. The portion of the saw-tooth wave form represented by the curve C indicating the change in conductance from a positive to a negative value is conventionally designated the trace portion thereof whereas the sudden change in conductance from a negative to a positive value, represented at the extreme right-hand portion of the curve C, is designated the retrace portion thereof. The curve C represents the conductance variation which would be established in the superregenerative amplifier I0 if the saw-tooth signal component from the generator of Fig. is alone applied to the superregenerator. However, the saw-tooth component is not delivered by itself but is accompanied by the sinusoidal component developed in the resonant circuit I2I, I22. The sinusoidal component has approximately the same frequency as the saw-tooth component and its amplitude and phase relative to the sawtooth component are so determined by the attenuating and phase-shifting network I30, I3I that the conductance-time characteristic of the superregenerative circuit has the form of curve D. Specifically, the amplitude of the sinusoidal component is small compared with the saw-tooth component, usually being one-quarter, or less. of the amplitude of the saw-tooth component. The phase relations established are preferably such that the slope of the characteristic D in the vicinity of the period of maximum sensitivity (when the conductance is. zero in an excursion from a positive to a negative value) is very much less than that of curve C. In other words, the sinusoidal component occurs in such time relation with respect to the major cycle as to effect on at least the trace portion of the saw-tooth wave form an undulation corresponding to a minor cycle of conductance variation in the oscillatory circuit superposed on the major cycle. As a result, the-slope of the conductance-time characteristic of the super-regenerative circuit in the vicinity of maximum sensitivity is very much less than the corresponding slope when the con ductance-time characteristic is determined solely by the saw-tooth signal component.

The improvement in selectivity resulting from I --.ance variation is ofsaw-tooth wave form as indicated by curve C of Fig. 6a. The curve E will be recognized as a parabola plotted in decibels. On the other hand, when the conductancetime characteristic of the superregenerator is in accordance with curve D of Fig. 6a, the selectivity is modified to that represented by the fullline curve F of Fig. 6b. It will be seen that the response of the receiver is a maximum at the oscillatory frequency fr of the superregenerative receiver and that points of reduced response occur at the frequencies f1 and ,fa, analogous to the corresponding designations explained in connection with Fig. 2b. It is apparent that the selectivity curve F is sharper within the frequency band 11-13: than is' the usual selectivity'represented by curve E.

One signal-generating network of the type shown in Fig. 5 found to have practical utility utilizes the following:

In the arrangement of Figs. 1, 3 and 5, the network for controlling the major conductance cycles and the network 'for determining the minor conductance cycles are coupled to the same transconductance-control electrodes of the regenerator vacuum tube included in the regenerative system. If desired, however, these networks may be coupled to different transconduct- 100 kiloance-control electrodes of the regenerator tube as indicated in the embodiment of the invention shown in Fig. '7. In the latter. the superregenerative amplifier includes a pentagrid type of vacuum tube 50 having anode and cathode electrodes and a series of intermediate control electrodes or grids 5|, 52, 53, 54, and 55. The second and fourth grids 52, 54 are connected together while the fifth grid 55 is conductively connected to the cathode. A unidirectional potential source +Sc is coupled to the grids 52 and 54 through a decoupling resistor 56 by-passed by a condenser 51. Circuit arrangements are associated witlr the cathode, the first grid 5I and the anode of the tube 50 to constitute a selfquenching superregenerative amplifier which is generally similar to the superregenerative amplifier of Fig. 1. These circuits include a frequency-determining circuit comprising an, inductor 00, a damping resistor 6|. and

condensers

62, 63, and 64. The cathode of the tube 50 is conductively connected to the junction of condensers 62 and G3 and is grounded through a. signal-frequency choke coil 65. The anode is "directly connected to one terminal of the resonant circuit -64 and the first grid 5| is coupled helothr terminal througha condenser 86. Resistors 81 and cam conjunction with 'a-con denser -89 constitutes a, quench-frequency sta- 1 13 inductivelycoupled with inductor 68. The

input terminals II, 12 may be connected to any suitable signal source, such as an antenna which intercepts modulated carrier-wave signals for superregenerative amplification. vAn amplified output signal maybe derived from an inductor 14 coupled'to the inductor 88 and connected to outputterminais' 18, 18. Any desired utilizing circuit may be connected with the outputterminals 15, I6 to receive the signal output of, the regenerative amplifier.

The Fig.1 arrangement as thus far described is a prior grid-stabilized gride-quenching superr'egenerative amplifier-in which the quenching action is analogous to that of the conventional blocking oscillator. During negative-conductance intervals of the regenerative circuit, oscillations are'produced at a frequency determined by, the resonant frequency of the circuit 68-84'. During the generation of such oscillations; peak rectification of the oscillations in the circuit of the grid I establishes a charge in the condenser 68 which builds up and blocks the tube 58. At

such time, the regenerative system enters upon its positive-conductance interval which endures until the "charge in the blocking. condenser 68 is dissipated to permit the tube 58 to be conductive again and to initiate the next succeeding interval of negative conductance. These conductance variations are the major conductance cycles which provide superregenerative action; v

The minor conductance variations, desired to be superimposed on such major conductance cyistic, are under the control of a signal-generating network in the form of a resonant circuit 11, I8 connected to the third grid 53. The resonant frequency of .the circuit 11, I8 .determines the nected to the anode, cathode and first grid 5| of the tube58. f 'During oscillation generating intervals, gridvcurrent flows in the circuit of the third grid 53 as indicated by the curve H. Such current now excites the signal-generating network 11, 18 to develop a signal having the damped sinu-.

- soidal wave form represented by curve J. This signal is applied to the third grid 53 and varies the transconductance of the tube. 58, thereby to produce the minor conductance cycles within the I ,dutatiflfiiotgand synchronously with the major 1 conductance cycles.

.. Q Althoughathe invention has been described as featuringa single network for generating a peri- 'odic sig'nal to accomplish minor conductance cy- ,.clesf 'oi'.thecontrolled regenerative system, there -may'be a plurality of such networks for further shaping the selectivity characteristic., :While multiple signal-generating networks may be employed in superregenerative amplifiers 01' either the-selt-quenching or separately quenched type, their application to a gridblocking grid-stabilized self-quenching amplifier has been shown in Fig. 9. The amplifier there represented includes a triode vacuum tube" having a frequency-determining circuit 8 I--'-85. The anode and cathode electrodes of the tube 88 are connected with'the resonant circuit 8I85 inessentially the same way as described in connection with the embodiment of Fig. 1. The control electrode is coupled to the resonant circuit through condensers 88 and 8'I in series and is stabilized by the stabilizing network 'comprised by

resistors

88 and 89, a condenser 98, and a source of unidirectional potential +B. This circuit arrangement constitutes a grid-blocking grid-stabilized superregenerative amplifier of the type which is fully explained in applicant's copending application Serial No. 788,765,filed November 28, 1947, entitled Self-Quench Superregenerative Receiver," and assigned to the same assignee as the present invention.

Signals applied to input terminals 9I and a2 are supplied to the supperregenerative amplifier through the inductive coupling between an inductor 93 and the inductor 8| of the resonant circuit 8I--85. Output signals. from the ampliher are delivered to output terminals 94, 95 by way of an additional inductor 96 also inductively coupled with the inductor 8| of the resonant circles in order to shape'the selectivity charactercult 8I85.

Periodic signals of sinusoidal wave form reli upon to introduce minor cycles of conductance variations in order to shape the selectivity characteristic are developed in a network coupled to thecontrol electrode of the tube 88. This network comprises shunt-connected

condensers

88, 91, and 98 and series inductors 99, I88, and I M For convenience, that network may be thought of as including a first resonant circuit I82, a second resonant circuit I 83, and a third resonant circuit I84. Each of these resonant circuits develops an alternating signal component of a different frequency higher than, but of the same order of magnitude as, the major conductance cycle established by the grid-locking condenser 81 and its charging and discharging circuits. The periodic signals generated by such resonant circuits superimpose a plurality of minor cycles of conductance variation on the major conductance cycle established by the grid-blocking network, including the condenser 81. Such minor cycles of conductance variation individually modify the selectivity characteristic by introducing reducedresponse serrations of the type represented in cumulative effects of the several circuits I82, I88.

and I84 influence the response of the superregenerative circuit and control the locations and depths of the reduced-response serrations.

It has been convenient in describing particular embodiments of the invention to discuss its application to the reception and amplification of amplitude-modulated wave signals but, as understood by those skilled in the art, superregenerative systems of the type under consideration may likewise be employed for the translation of frequency or angular modulated wave signals. Since the instant invention is directed primarily to shaping the selectivity characteristic of a superregenerative stage, it may be advantageously used where the signal to be translated is frequencymodulated or angular-velocity modulated. Further, a superregenerative receiver embodying the invention may operate in' the linear as well as in the logarithmic mode.

superregenerative systems incorporating the present invention have decided advantages over those heretofore known in the art. In particular, they have a selectivity characteristic with reduced-response serrations or trap effects of controllable depth occurring at preselectable frequencies. Furthermore, the serrations in the selectivity characteristic appear in every major quench cycle, thereby avoiding limitations of other known arrangements which possess serrated selectivity characteristics but only after the occurrence of several quench cycles.

present considered to be the preferred embodithe frequency of said major cycle but which is substantially less than one-half said predetermined oscillatory frequency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to eflect in at least said portion of said cycle'an undulation corresponding to the superposing of a minor cycle of conductance variation on said major, cycle; and coupling means for applying said periodic signal component to said regenerative circuit, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle.

3. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuithaving a predetermined oscillatory frequency; quench means coupled to said circuit for effecting a major cycle of conductance variation in said circuit to' provide superregenerative ments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

l. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for effecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; a signal-generating network so proportioned as to develop a periodic signal component which has a frequency within a range of one and one-half to ten times the frequency of said major cycle but which is substantially less than one-half said predetermined oscillatory frequency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle; and coupling means for applying said periodic signal frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscil-' latory frequency and related to the occurrence of said minor cycle within said major cycle.

2. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for periodically effecting a major cycle of conductance variation in said circuit .to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; a signal-generating network so proportioned as periodically to develop a periodic signal component which has a frequency within the range of two to, five times amplification Of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; a signal-generating network synchronized with said quench means so proportioned as to develop a periodic signal component which has a frequency within a range of one and onehalf to ten times the frequency of said major cycle but which is substantially less than onehalf said predetermined oscillatory frequency,

and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance'variation on said major cycle; and coupling means for applying said periodic signal component to said regenerative circuit, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle.

4 A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for eflecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; a signal-generating network so proportioned as to develop a periodic signal component which has a duration substantially that of said major cycle, and which has a frequency within a range of one and one-half to ten times the frequency of said major cycle but which is substantially less than one-half said predetermined oscillatory frequency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to eilect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle; and coupling means for applying said periodic signal component to said regenerative circuit, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency A superregenerative wave-signal, translating system comprising: a--regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for effecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; and a signal-generating network included in said circuit so proportioned as to develop a periodic signal component which has a frequency within a range of one and one-half to ten'times the frequency of said major cycle but which is substantially less than one-half said predetermined oscillatory frequency and which occurs in such time relation with respect to said major cycle when applied to said regenerative .circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major. cycle, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said' oscillatory frequency and related to the occurrence of said minor cycle within said major cycle.

. 6. A superregenerativewave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for effecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; and a signal-generating network included in said circuit to be excited concurrently with said quench means so proportioned as to develop a periodic signal component which has a frequency within a range of one and onehalf to ten times the frequency of said major cycle but which is substantially less than onehalf said predetermined oscillatory frequency and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle wthin said major cycle.

7. A self-quenching superregenerative wavesignal translating system comprising:' a regenerative oscillatory crcuit having a predetermined oscillatory frequency; self-quenching means included in said circuit for effecting a major cycle of conductance variation therein to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; and a signalgenerating. network included in said circuit so proportioned as to develop a periodic signal component which has a frequency within a range of one and one-half to ten times the frequency of said major cycle but which is substantially less than one-half said predetermined oscillatory frequency'and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle. k 3

8. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for effecting a major cycle of conductance variation in said circuit to provide superregenerative ampliflcation of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle; and coupling means for applying said alternating signal component to said regenerative circuit, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle.

9. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for effecting a major cycle of conductance variation in said circuit to provide superregenerative ampliflcation of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; a signal-generating network so proportioned as to develop a periodic signal component which has a frequency higher than, but within a range of one and one-half to ten times the frequency of said major cycle but which is-substantially less than one-half said predetermined oscillatory frequency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle; and coupling means for applying said periodic signal component to said regenerative circuit, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle.

10. A superregenerative wave-signal translatefiecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value and including a network so proportioned as to develop a second periodic signal component which has a frequency within a range of one and one-half to ten times the frequency of said first periodic signal component but substantially less than one-half said predetermined oscillatory fre-- quency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle; and coupling means for applying said second periodic signal component to said regenerative circuit, whereby said superregenerative system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle. 7

- 11. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for effecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; a signal-generating network including a resonant circuit so proportioned as to develop an alternating signal component which has a frequency substantially one and one-half that of said major cycle but which is substantially less than one-half said predetermined oscillatory frequency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle anundulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle; and coupling means for applying said alternating signal component to said regenerative circuit, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response 20 quency of said first periodic signal component but substantially less than one-half said predetermined oscillatory frequency and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle, whereby said superregenerative sysserration at a frequency spaced in the frequency conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value and including a network so proportioned as to develop a second periodic signal component which has a frequency within a range of one and one-half to ten times the fretem has a. substantially uninterrupted frequencyresponse characteristic with at least one reduced- -response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle.

13. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; and a signal-generating system coupled to said circuit including means for developing a first periodic signal component of saw-tooth wave form for efiecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value and including a network so proportioned as to develop a second periodic signal component of sinusoidal wave form which has a frequency within a range of one and one-half to ten times the frequency of said first periodic signal component but substantially less than onehalf said predetermined oscillatory frequency and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle, whereby said superregenerative system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from having a portion representing a conductance change from a positive to a negative value; and a signal-generating network coupled to a second pair of said electrodes for developing and applying to said circuit a periodic signal component which has a frequency within a range of one and one-half to ten times the frequency of said major cycle and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of conductance variation on said major cycle, whereby said system has a substantially uninterrupted frequencyrespcnse characteristic with at least one reducedresponse serration at a frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle.

15. A superregenerative wave-signal translat- .21 ing system comprising: a regenerative oscillatory circuit having a predetermined oscillatory-frequency; quench means coupled to said circuit for efiecting a major cycleof conductance variation in said circuit to provide superregenerative am- I vplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; a signal-generating networkso proportioned as to develop a plurality of periodic signal components of different frequencies individually having a frequency within a range of one and onehalf to ten times the frequency of said major cycle but which is substantially less than onehalfsaid predetermined oscillatory frequency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the super-posing of a minor cycle of conductance variation on saidmajor cycle; and coupling means for applying said periodic signal component to said regenerative circuit, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency spaced in the frequency spectrum from said oscillatory frequency andrelated to the occurrenceof said minor cycle-within said major cycle.

16. A superregenerativewave-signal translat ing system comprising: a regenerative oscillatory circuit including vacuum-tube means and having a predetermined oscillatory frequency; quench means coupled to said vacuum-tube means for effecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; and a signal-generating network also coupled to said vacuum-tube means so proportioned as to develop and apply to said circuit a periodic signal component which has a freqeuncy within a range of one and one-half to ten times the frequency of said major cycle but which is substantially .less than oneehalf said predeter mined oscillatory frequency and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycleof conductance variation on said major cycle, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a, frequency spaced in the frequency spectrum from said oscillatory frequency and related to the occurrence of said minor cycle within said major cycle.

17. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; quench means coupled to said circuit for effecting a major cycle of conductance variation in said circuit to provide superregenerative amplification of a wave signal applied to said circuit, said cycle having a portion representing a conductance change from a positive to a negative value; and a signal-generating network included in said circuit to be shock excited in each quench cycle to develop a periodic signal component which has a frequency within a range of one and one-half to ten times the frequency frequency and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect in at least said portion of said cycle an undulation corresponding to the superposing of a minor cycle of condu'tance variation on said major cycle, whereby said system has a substantially uninterrupted frequency-response characteristic with at least one reduced-response serration at a frequency a signal-generating network so proportioned as.

to develop a sinusoidal signal component having a frequencysubstantially four times that of said major cycle but which is substantially ,less than one-half said predetermined oscillatory frequency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect on at least the trace portion of said sawtooth wave form an undulation corresponding to a minor cycle of conductance variation in said circuit superposed on said major cycleand coupling means for applying said sinusoidal signal component to said regenerative circuit, whereby the slope of the conductance-time characteristic of said circuit in the vicinityof the period of maximum sensitivity is substantially less than that attributable to said quench signal alone.

19. A superregenerative wave-signal translating system comprising; a regenerative oscillatory circuit having a predetermined oscillatory frequency; means coupled to said circuit for producing a quench signal for effecting a major cycle of conductance variation of saw-tooth wave form in-said circuit to provide superregenerative amplification of a wave signal applied to said circuit; a signal-generating network so proportioned as to develop a sinusoidal signal component having a frequency substantially four times that of said major cycle but which is substantially less than one-half said predetermined oscillatory frequency, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to effect on at least the trace portion of said saw-tooth wave form an undulation corresponde ing to a minor cycle of conductance variation in said circuit superposed on said major cycle; coupling means for applying said sinusoidal signal component to said circuit; and means for so adjusting the relative phase and magnitude of said quench signal and said sinusoidal component that the slope of the conductance-time characteristic of said circuit in the vicinity of the period of maximum sensitivity is substantially less than that attributable to said quench signal alone.

20. A superregenerative wave-signal translating system comprising: a regenerative oscillatory circuit having a predetermined oscillatory frequency; means coupled to said circuit for producing a quench signal for effecting a major cycle of conductance variation of saw-tooth wave form in said circuit to provide superregenerative 23 amplification or a wave signal applied to said circuit; a signal-generating network for developing a sinusoidal signal component having a frequency substantially four'times that oi said major cycle, and which occurs in such time relation with respect to said major cycle when applied to said regenerative circuit to eflect on at least the trace portion of said saw-tooth wave form an undulation corresponding to a minor cycle oi conductance variation in said circuit superposed on said major cycle; coupling means for, applying said sinusoidal signal component to said circuit; and means, including a signal-attenuating and phase-shifting network, for applying said quench signal and said sinusoidal component to said regenerative circuit with such relative amplitude and phase that the slope of the conductance-time characteristic of said circuit in the vicinity of the period of maximum sensitivity is substantially less than that attributable to said quench signal alone.

DONALD RICHMAN.

REFERENCES CITED The iollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,917,113 Gunther July 4, 1933 2,100,605 Linsell Nov. 30, 1937 2,212,182 Paddle Aug. 20, 1940 2,273,090 Crosby Feb. 17, 1942