1024:) and "German small receivers" (DKE, Deutscher Kleinempfänger). Even after WWII, the regenerative design was still present in early after-war German minimal designs along the lines of the "peoples receivers" and "small receivers", dictated by lack of materials. Frequently German military tubes like the "RV12P2000" were employed in such designs. There were even superheterodyne designs, which used the regenerative receiver as a combined IF and demodulator with fixed regeneration. The superregenerative design was also present in early FM broadcast receivers around 1950. Later it was almost completely phased out of mass production, remaining only in hobby kits, and some special applications, like gate openers.
755:
frequency plate voltage divided by radio frequency input voltage) of only 9.2 at 7.2 MHz, but in a regenerative detector, had detection gain as high as 7,900 at critical regeneration (non-oscillating) and as high as 15,800 with regeneration just above critical. The "... non-oscillating regenerative amplification is limited by the stability of the circuit elements, tube characteristics and supply voltages which determine the maximum value of regeneration obtainable without self-oscillation". Intrinsically, there is little or no difference in the gain and stability available from vacuum tubes, JFETs, MOSFETs or bipolar junction transistors (BJTs).
1033:
194:
1063:
the 30 to 6,000 MHz range. It removes the need for the operator to manually adjust regeneration level to just below the point of oscillation - the circuit automatically is taken out of oscillation periodically, but with the disadvantage that small amounts of interference may be a problem for others. These are ideal for remote-sensing applications or where long battery life is important. For many years, superregenerative circuits have been used for commercial products such as garage-door openers, radar detectors, microwatt RF data links, and very low cost walkie-talkies.
51:
27:
884:(RF). TRF receivers often required 5 or 6 tubes; each stage requiring tuning and neutralization, making the receiver cumbersome, power hungry, and hard to adjust. A regenerative receiver, by contrast, could often provide adequate reception with the use of only one tube. In the 1930s the regenerative receiver was replaced by the superheterodyne circuit in commercial receivers due to the superheterodyne's superior performance and the falling cost of tubes. Since the advent of the
766:. Providing the oscillation separately from the detector allows the regenerative detector to be set for maximum gain and selectivity - which is always in the non-oscillating condition. Interaction between the detector and the beat oscillator can be minimized by operating the beat oscillator at half of the receiver operating frequency, using the second harmonic of the beat oscillator in the detector.
782:(a loop gain of just less than one). The result of this is to greatly increase the gain of the amplifier at the bandpass frequency (resonant frequency), while not increasing it at other frequencies. So the incoming radio signal is amplified by a large factor, 10 - 10, increasing the receiver's sensitivity to weak signals. The high gain also has the effect of reducing the circuit's
940:
931:. Simple regenerative receivers electrically couple the antenna to the detector tuned circuit, resulting in the electrical characteristics of the antenna influencing the resonant frequency of the detector tuned circuit. Any movement of the antenna or large objects near the antenna can change the tuning of the detector.
1046:
exponentially, starting from the tiny energy picked up by the antenna plus circuit noise. The amplitude reached at the end of the quench cycle (linear mode) or the time taken to reach limiting amplitude (log mode) depends on the strength of the received signal from which exponential growth started. A
911:
A disadvantage of this receiver, especially in designs that couple the detector tuned circuit to the antenna, is that the regeneration (feedback) level must be adjusted when the receiver is tuned to a different frequency. The antenna impedance varies with frequency, changing the loading of the input
1062:
Superregeneration is most valuable above 27 MHz, and for signals where broad tuning is desirable. The superregen uses many fewer components for nearly the same sensitivity as more complex designs. It is easily possible to build superregen receivers which operate at microwatt power levels, in
1058:
Superregenerative detectors work well for AM and can also be used for wide-band signals such as FM, where they perform "slope detection". Regenerative detectors work well for narrow-band signals, especially for CW and SSB which need a heterodyne oscillator or BFO. A superregenerative detector does
1045:
or by using a second oscillator stage) to provide single-device circuit gains of around one million. This second oscillation periodically interrupts or "quenches" the main RF oscillation. Ultrasonic quench rates between 30 and 100 kHz are typical. After each quenching, RF oscillation grows
977:
were expensive and consumed much power, with the added expense and encumbrance of heavy batteries. So this design, getting most gain out of one tube, filled the needs of the growing radio community and immediately thrived. Although the superheterodyne receiver is the most common receiver in use
754:
Regeneration can increase the detection gain of a detector by a factor of 1,700 or more. This is quite an improvement, especially for the low-gain vacuum tubes of the 1920s and early 1930s. The type 36 screen-grid tube (obsolete since the mid-1930s) had a non-regenerative detection gain (audio
249:). It is desirable for the circuit design to provide regeneration control that can gradually increase feedback to the point of oscillation and that provides control of the oscillation from small to larger amplitude and back to no oscillation without jumps of amplitude or hysteresis in control.
237:. In regenerative receivers using only one active device, the same tuned circuit is coupled to the antenna and also serves to select the radio frequency to be received, usually by means of variable capacitance. In the regenerative circuit discussed here, the active device also functions as a
1805:(8) : 244-260. From p. 252: " ... a free oscillation starts every time the resistance of the circuit becomes negative. ... The free oscillations produced in the system when no signaling emf. is impressed, must be initiated by some irregularity of operation of the vacuum tubes, ... ."
1117:
819:), the feedback is increased just to the point of oscillation. The tuned circuit is adjusted to provide typically 400 to 1000 Hertz difference between the receiver oscillation frequency and the desired transmitting station's signal frequency. The two frequencies
229:. Because of the large amplification possible with regeneration, regenerative receivers often use only a single amplifying element (tube or transistor). In a regenerative receiver the output of the tube or transistor is connected back to its own input through a
965:
filed US patent 1170881 in 1914 that became the cause of a contentious lawsuit with
Armstrong, whose patent for the regenerative circuit had been issued in 1914. The lawsuit lasted until 1934, winding its way through the appeals process and ending up at the
1104:
1091:
1075:
receiver mixing additional unneeded signals from those bands into the working frequency. Thus the overall bandwidth of superregenerator cannot be less than 4 times that of the quench frequency, assuming the quenching oscillator produces an ideal sine wave.
926:
Other shortcomings of regenerative receivers are the sensitive and unstable tuning. These problems have the same cause: a regenerative receiver's gain is greatest when it operates on the verge of oscillation, and in that condition, the circuit behaves
1130:
915:
A disadvantage of the single active device regenerative detector in autodyne operation is that the local oscillation causes the operating point to move significantly away from the ideal operating point, resulting in the detection gain being reduced.
1036:
Edwin
Armstrong presenting the superregenerative receiver at the June 28, 1922 meeting of the Radio Club of America in Havemeyer Hall, Columbia University, New York. His prototype 3 tube receiver was as sensitive as conventional receivers with 9
981:
In World War II the regenerative circuit was used in some military equipment. An example is the German field radio "Torn.E.b". Regenerative receivers needed far fewer tubes and less power consumption for nearly equivalent performance.
54:
Rear view of the above radio, showing the simplicity of the regenerative design. The tickler coil is visible inside the tuning coil and is turned by a shaft from the front panel; this type of adjustable transformer was called a
260:. The regenerative detector provides sensitivity and selectivity due to voltage amplification and the characteristics of a resonant circuit consisting of inductance and capacitance. The regenerative voltage amplification
1066:
Because the superregenerative detectors tend to receive the strongest signal and ignore other signals in the nearby spectrum, the superregen works best with bands that are relatively free of interfering signals. Due to
684:
1143:
166:, was also invented by Armstrong in 1922. It was never widely used in general commercial receivers, but due to its small parts count it was used in specialized applications. One widespread use during WWII was
912:
tuned circuit by the antenna, requiring the regeneration to be adjusted. In addition, the Q of the detector tuned circuit components vary with frequency, requiring adjustment of the regeneration control.
1764:*, vol. 2612**, pages 136-145 (December 1995). (* SPIE = Society of Photo-optical Instrumentation Engineers; renamed: International Society for Optical Engineering) (** Jaafar M.H. Elmirghani, ed.,
1020:
design began to gradually supplant the regenerative receiver, as tubes became far less expensive. In
Germany the design was still used in the millions of mass-produced German "peoples receivers" (
888:
in 1946, the low cost of active devices has removed most of the advantage of the circuit. However, in recent years the regenerative circuit has seen a modest comeback in receivers for low cost
833:
frequencies. The difference frequency, typically 400 to 1000 Hertz, is in the audio range; so it is heard as a tone in the receiver's speaker whenever the station's signal is present.
345:
749:
477:
1050:
in the audio amplifier filters the quench and RF frequencies from the output, leaving the AM modulation. This provides a crude but very effective automatic gain control (AGC).
923:
to other nearby receivers. Adding an RF amplifier stage between the antenna and the regenerative detector can reduce unwanted radiation, but would add expense and complexity.
575:
506:
287:
1059:
not have a usable heterodyne oscillator – even though the superregen always self-oscillates, so CW (Morse code)and SSB (single side band) signals can't be received properly.
1976:, pp 46–55. Appellate court credited De Forest with the regenerative circuit: "The decisions of the Commissioner are reversed and priority awarded to De Forest." p 55.
758:
A major improvement in stability and a small improvement in available gain for reception of CW radiotelegraphy is provided by the use of a separate oscillator, known as a
414:
704:
595:
546:
526:
434:
385:
365:
2023:
1867:
955:, filed US patent 1113149 in 1913 about regenerative circuit while he was a junior in college. He patented the superregenerative circuit in 1922, and the
85:). Some of the output of the amplifying device is applied back to its input to add to the input signal, increasing the amplification. One example is the
1234:
1009:
receivers, and was the major technical development which led to the wartime development of radio-controlled weapons and the parallel development of
1994:
Ulrich L. Rohde, Ajay Poddar www.researchgate.net/publication/4317999_A_Unifying_Theory_and_Characterization_of_Super-Regenerative_Receiver_(SRR)
1932:
1658:
1634:
1540:
860:(SSB) signals, the circuit is also adjusted to oscillate as in CW reception. The tuning is adjusted until the demodulated voice is intelligible.
600:
173:, where single tuned circuit completed the entire electronics system. It is still used in a few specialized low data rate applications, such as
880:, thus reducing the number of tubes required and therefore the cost of a receiver. Early vacuum tubes had low gain and tended to oscillate at
147:
and is largely considered obsolete. Regeneration (now called positive feedback) is still widely used in other areas of electronics, such as in
120:. Advantages of regenerative receivers include increased sensitivity with modest hardware requirements, and increased selectivity because the
221:, can be increased by feeding some of the energy from its output back into its input in phase with the original input signal. This is called
1880:
135:
Due partly to its tendency to radiate interference when oscillating, by the 1930s the regenerative receiver was largely superseded by other
1612:
1529:
1115:, Armstrong, E. H., "Method of receiving high frequency oscillation", published February 8, 1919, issued June 8, 1920
162:
A receiver circuit that used larger amounts of regeneration in a more complicated way to achieve even higher amplification, the
1469:
1201:
1582:
1495:
970:. Armstrong won the first case, lost the second, stalemated at the third, and then lost the final round at the Supreme Court.
919:
Another drawback is that when the circuit is adjusted to oscillate it can radiate a signal from its antenna, so it can cause
1279:
201:, in which the feedback was applied to the input (grid) of the tube with a "tickler coil" winding on the tuning inductor.
1347:
528:
represents the total dissipative loss of the tuned circuit. The positive feedback compensates the energy loss caused by
1418:
967:
1408:
1071:, its quenching frequency must be at least twice the signal bandwidth. But quenching with overtones acts further as a
1005:
below its ignition voltage, allowing it to amplify analog signals as a self-quenching superregenerative detector in
1442:
1768:-- a collection of papers presented at the SPIE conference of 23–24 October 1995 in Philadelphia, Pennsylvania.)
1951:
1479:
1452:
1289:
869:
292:
136:
2014:
1089:, Armstrong, E. H., "Wireless receiving system", published Oct. 6, 1914, issued Oct. 29, 1913
783:
848:
predates multigrid tubes and is not applied to use of tubes specifically designed for frequency conversion.
2049:
2008:
1362:
1102:, de Forest, Lee, "Wireless receiving system", published Feb. 8, 1916, issued Mar. 12, 1914
990:
920:
167:
20:
1749:
1734:
709:
439:
1969:
1721:
156:
2044:
857:
128:
around the tuned circuit (via a "tickler" winding or a tapping on the coil) because it introduces some
1760:
Domine M.W. Leenaerts and Wim M.G. van
Bokhoven, “Amplification via chaos in regenerative detectors,”
1138:
1128:, Armstrong, E. H., "Signalling system", published June 27, 1921, issued July 25, 1922
1125:
1112:
1099:
1086:
551:
482:
263:
2059:
2054:
1980:
Robinson, H. A. (February 1933), "Regenerative
Detectors, What We Get From Them - How To Get More",
108:
The regenerative receiver was invented in 1912 and patented in 1914 by
American electrical engineer
1306:
1163:
144:
868:
Regenerative receivers require fewer components than other types of receiver circuit, such as the
1895:
1332:
1032:
1010:
836:
Demodulation of a signal in this manner, by use of a single amplifying device as oscillator and
1791:
876:. The circuit's advantage was that it got much more amplification (gain) out of the expensive
2004:
1795:
1259:
1186:
1815:
148:
124:
of the tuned circuit will be increased when the amplifying vacuum tube or transistor has its
775:
198:
390:
193:
8:
791:
178:
129:
113:
1961:
939:
2022:(2nd Cir. 1926) 10 F.2d 727, February 8, 1926; cert denied 270 U.S. 663, 46 S.Ct. 471.
1589:
1506:
1374:
893:
778:
reception, the gain of the loop is adjusted so it is just below the level required for
689:
580:
531:
511:
419:
370:
350:
245:. A regeneration control is usually provided for adjusting the amount of feedback (the
238:
234:
206:
174:
102:
1947:
1779:
IEEE Transactions on
Circuits and Systems Part 1: Fundamental Theory and Applications
1669:
1475:
1448:
1414:
1285:
1219:
222:
74:
1471:
Short-range
Wireless Communication: Fundamentals of RF System Design and Application
1021:
1378:
1366:
197:
Vacuum tube regenerative receiver schematic. Most regenerative receivers used this
1794:
noted signs of chaotic behavior in his circuits. See: Edwin H. Armstrong (1922)
50:
26:
1859:
1683:
R. J. Talbert, "The Simple
Regenerative Receiver with Separate Beat Oscillator",
1158:
1068:
1047:
1017:
956:
952:
948:
881:
873:
837:
812:
809:
140:
109:
94:
86:
1370:
994:
820:
2038:
1382:
1006:
962:
897:
889:
230:
182:
152:
125:
1307:"A history of the regeneration circuit: From invention to patent litigation"
34:
radio with construction characteristic of the 1930s - 40s. The controls are
1264:. Dept. of the Army, US Government Printing Office. 1952. pp. 187–190.
1168:
928:
117:
57:
1777:
Domine M.W. Leenaerts, “Chaotic behavior in superregenerative detectors,”
1041:
The superregenerative receiver uses a second lower-frequency oscillation (
679:{\displaystyle Q_{\mathrm {reg} }=X_{\mathrm {L} }/(R-|R_{\mathrm {r} }|)}
974:
877:
779:
210:
170:
1261:
Technical Manual TM 11-665: C-W and A-M Radio
Transmitters and Receivers
1072:
905:
885:
826:
816:
214:
387:
is the portion of the output signal fed back to the L2 C2 circuit. As
233:(LC circuit). The tuned circuit allows positive feedback only at its
1042:
998:
246:
70:
31:
1701:
R. De Cola, "Increased Sensitivity With the Regenerative Detector",
1001:
marketed in 1938, which was designed specifically to operate like a
1968:. History of radio in 1925. Has May 5, 1924, appellate decision by
1891:
1790:
In 1922, during his development of the superregenerative receiver,
989:, found several highly important military uses in World War II in
978:
today, the regenerative radio made the most out of very few parts.
803:
787:
121:
1826:(1), Garden City, NY: Doubleday, Page & Co.: 71–72, May 1922
2005:
Some Recent Developments in the Audion Receiver by EH Armstrong
1141:, Braden, R. A., "Superregenerative magnetron receiver"
1002:
218:
1410:
The Race for Wireless: How Radio Was Invented (or Discovered?)
1206:, 4th ed., London: Sir Isacc Pitman & Sons, 1961, p. 151
901:
548:, so it may be viewed as introducing a negative resistance
2020:
Armstrong v. De Forest Radio Telephone & Telegraph Co.
1613:
E. E. Zepler, "Oscillation Hysteresis in Grid Detectors",
1982:
1703:
1685:
1568:
1649:, 2nd ed., New York: John Wiley and Sons, 1951, p. 168
1500:(Part I), New York: John Wiley and Sons, 1943, p. 392"
973:
At the time the regenerative receiver was introduced,
712:
692:
603:
583:
554:
534:
514:
485:
442:
436:
of the tuned circuit (L2 C2) without regeneration is
422:
393:
373:
353:
295:
266:
1796:"Some recent developments of regenerative circuits,"
1312:. Institute of Electrical and Electronics Engineers
1191:, 4th ed., London, U. K.: Newnes, 1999, p. 265, 269
1739:, 2nd ed. Washington, DC: U.S.G.P.O., 1922, p. 501
743:
698:
678:
589:
569:
540:
520:
500:
471:
428:
408:
379:
359:
339:
281:
143:) and especially by another Armstrong invention -
1348:"Some recent developments in the Audion receiver"
1336:, filed October 29, 1913, granted October 6, 1914
1239:, London: The Amalgamated Press LTD., 1933, p. 94
416:becomes smaller the amplification increases. The
252:Two important attributes of a radio receiver are
21:Heat exchanger § Regenerative heat exchanger
2036:
1913:
1799:Proceedings of the Institute of Radio Engineers
993:identification equipment and in the top-secret
863:
797:
1324:
1053:
1781:, vol. 43, no. 3, pages 169-176 (March 1996).
1737:The Principles Underlying Radio Communication
1224:, 2nd ed. New York: McGraw-Hill, 1937, p. 463
1027:
93:), but the most common use of the term is in
1630:
1628:
1626:
1624:
1562:
1560:
1558:
1556:
1554:
1552:
1436:
1434:
1432:
1430:
1215:
1213:
1679:
1677:
1566:H. A. Robinson, "Regenerative Detectors",
1545:, New York: McGraw-Hill, 1947, pp. 741-744
1406:
1400:
1254:
1252:
1250:
1248:
1246:
597:of the tuned circuit with regeneration is
367:is the non-regenerative amplification and
30:Homebuilt Armstrong one-tube regenerative
16:Electronic circuit using positive feedback
1944:Empire of the Air: the men who made radio
1697:
1695:
1345:
1124:
1111:
1098:
1085:
340:{\displaystyle u_{\mathrm {o} }=u/(1-ua)}
1979:
1621:
1617:, vol. XXIII, no. 275, Aug. 1946, p. 222
1549:
1444:The New Radio Receiver Building Handbook
1440:
1427:
1339:
1330:US Patent 1113149A, Edwin H. Armstrong,
1210:
1031:
997:. An example here is the miniature RK61
938:
192:
188:
49:
25:
1674:
1273:
1271:
1243:
825:in the nonlinear amplifier, generating
2037:
2015:a one transistor regenerative receiver
1707:, vol. XVIII, no. 12, p. 24, Dec. 1934
1692:
1467:
1461:
1346:Armstrong, Edwin H. (September 1915).
1281:Basic Radio: Principles and Technology
116:. It was widely used between 1915 and
1959:
1946:, New York: Edward Burlingame Books,
1941:
1933:Cruft Electronics Staff, 1947, p. 744
1848:
1836:
1659:Cruft Electronics Staff, 1947, p. 741
1635:Cruft Electronics Staff, 1947, p. 743
1277:
790:) by an equal factor, increasing the
2011:), volume 3, 1915, pp. 215–247.
1750:Signal Corps U.S. Army, 1922, p. 503
1572:, vol. XVII, no. 2, p. 26, Feb. 1933
1268:
943:1915 Armstrong regenerative receiver
744:{\displaystyle |R_{\mathrm {r} }|=R}
472:{\displaystyle Q=X_{\mathrm {L} }/R}
209:of any amplifying device, such as a
1689:, vol. XX, no. 2, p. 15, Feb. 1936
13:
1766:Chaotic Circuits for Communication
1583:"K. R. Sturley, 1943, pp. 394-395"
1137:
724:
662:
631:
616:
613:
610:
561:
492:
455:
302:
273:
241:; this circuit is also known as a
14:
2071:
1998:
1883:Subminiature gas triode type RK61
686:. The regeneration increases the
508:is the reactance of the coil and
1304:
1189:Newnes Dictionary of Electronics
851:
570:{\displaystyle R_{\mathrm {r} }}
501:{\displaystyle X_{\mathrm {L} }}
282:{\displaystyle u_{\mathrm {o} }}
112:when he was an undergraduate at
1926:
1921:Radio Control for Models (1950)
1873:
1853:
1842:
1830:
1808:
1784:
1771:
1754:
1743:
1728:
1710:
1663:
1652:
1639:
1606:
1575:
1534:
1523:
1488:
1447:. Lulu. pp. 24–26, 31–32.
1441:Williams, Lyle Russell (2006).
769:
1530:E. Williams, 1961, pp. 156-158
1298:
1228:
1195:
1180:
731:
714:
673:
669:
652:
642:
334:
319:
139:receiver designs (for example
1:
1966:, London: Ernest Benn Limited
1647:The Technique of Radio Design
1543:Electronic Circuits and Tubes
1174:
105:of a single amplifier stage.
2031:, 13 F.2d 438 (2d Cir. 1926)
2009:Institute of Radio Engineers
1718:The Radio Amateur's Handbook
1407:Malanowski, Gregory (2011).
1363:Institute of Radio Engineers
864:Advantages and disadvantages
840:simultaneously, is known as
798:CW reception (autodyne mode)
7:
1970:Josiah Alexander Van Orsdel
1722:American Radio Relay League
1670:W. L. Everitt, 1937, p. 464
1413:. AuthorHouse. p. 66.
1152:
1054:Advantages and applications
97:amplifiers, and especially
10:
2076:
2007:, Proceedings of the IRE (
1371:10.1109/JRPROC.1915.216677
1237:The Manual of Modern Radio
1079:
1028:Superregenerative receiver
1011:radio controlled modelling
987:superregenerative detector
934:
801:
706:. Oscillation begins when
577:to the tuned circuit. The
164:superregenerative receiver
101:, to greatly increase the
89:(which is also known as a
18:
1963:Radio: Beam and Broadcast
1724:. 1978. pp. 241–242.
1541:Cruft Electronics Staff,
1333:Wireless receiving system
1222:Communication Engineering
1204:Thermionic Valve Circuits
145:superheterodyne receivers
1735:Signal Corps U.S. Army,
1187:S. W. Amos, R. S. Amos,
1164:Tuned electrical circuit
1919:George Honnest-Redlich
1284:. Newnes. p. 100.
985:A related circuit, the
157:bootstrapped amplifiers
91:regenerative comparator
2029:Armstrong v. De Forest
1863:
1816:"The Armstrong Patent"
1038:
944:
745:
700:
680:
591:
571:
542:
522:
502:
473:
430:
410:
381:
361:
341:
283:
202:
99:regenerative receivers
62:
47:
2024:opinion on leagle.com
1974:De Forest v Armstrong
1960:Morse, A. H. (1925),
1498:Radio Receiver Design
1474:. Newnes. p. 1.
1468:Bensky, Alan (2004).
1043:within the same stage
1035:
942:
892:applications such as
856:For the reception of
808:For the reception of
760:heterodyne oscillator
746:
701:
681:
592:
572:
543:
523:
503:
474:
431:
411:
382:
362:
342:
284:
243:regenerative detector
196:
189:Regenerative receiver
73:circuit that employs
53:
29:
844:reception. The term
710:
690:
601:
581:
552:
532:
512:
483:
440:
420:
409:{\displaystyle 1-ua}
391:
371:
351:
293:
264:
67:regenerative circuit
19:For other uses, see
2050:Electronic circuits
1990:(2): 26–30 & 90
1942:Lewis, Tom (1991),
1762:Proceedings of SPIE
1278:Poole, Ian (1998).
894:garage door openers
179:wireless networking
175:garage door openers
130:negative resistance
114:Columbia University
42:filament rheostat,
1864:Tornisterfunkgerät
1235:J. Scott-Taggart,
1039:
1016:In the 1930s, the
959:receiver in 1918.
945:
741:
696:
676:
587:
567:
538:
518:
498:
469:
426:
406:
377:
357:
337:
279:
235:resonant frequency
203:
141:"reflex" receivers
63:
48:
2045:Radio electronics
1615:Wireless Engineer
1069:Nyquist's theorem
904:readers and some
882:radio frequencies
794:of the receiver.
699:{\displaystyle Q}
590:{\displaystyle Q}
541:{\displaystyle R}
521:{\displaystyle R}
429:{\displaystyle Q}
380:{\displaystyle a}
360:{\displaystyle u}
223:positive feedback
199:Armstrong circuit
75:positive feedback
46:tuning capacitor.
2067:
2060:Receiver (radio)
2055:History of radio
1991:
1967:
1956:
1935:
1930:
1924:
1917:
1911:
1910:
1908:
1906:
1901:on 20 March 2017
1900:
1894:. Archived from
1892:Raytheon Company
1889:
1877:
1871:
1857:
1851:
1846:
1840:
1834:
1828:
1827:
1812:
1806:
1788:
1782:
1775:
1769:
1758:
1752:
1747:
1741:
1732:
1726:
1725:
1714:
1708:
1699:
1690:
1681:
1672:
1667:
1661:
1656:
1650:
1643:
1637:
1632:
1619:
1610:
1604:
1603:
1601:
1600:
1594:
1588:. Archived from
1587:
1579:
1573:
1564:
1547:
1538:
1532:
1527:
1521:
1520:
1518:
1517:
1511:
1505:. Archived from
1504:
1496:"K. R. Sturley,
1492:
1486:
1485:
1465:
1459:
1458:
1438:
1425:
1424:
1404:
1398:
1397:
1395:
1393:
1388:on July 28, 2013
1387:
1381:. Archived from
1352:
1343:
1337:
1328:
1322:
1321:
1319:
1317:
1311:
1302:
1296:
1295:
1275:
1266:
1265:
1256:
1241:
1232:
1226:
1217:
1208:
1199:
1193:
1184:
1147:
1146:
1142:
1134:
1133:
1129:
1121:
1120:
1116:
1108:
1107:
1103:
1095:
1094:
1090:
947:The inventor of
786:(increasing the
750:
748:
747:
742:
734:
729:
728:
727:
717:
705:
703:
702:
697:
685:
683:
682:
677:
672:
667:
666:
665:
655:
641:
636:
635:
634:
621:
620:
619:
596:
594:
593:
588:
576:
574:
573:
568:
566:
565:
564:
547:
545:
544:
539:
527:
525:
524:
519:
507:
505:
504:
499:
497:
496:
495:
478:
476:
475:
470:
465:
460:
459:
458:
435:
433:
432:
427:
415:
413:
412:
407:
386:
384:
383:
378:
366:
364:
363:
358:
346:
344:
343:
338:
318:
307:
306:
305:
288:
286:
285:
280:
278:
277:
276:
2075:
2074:
2070:
2069:
2068:
2066:
2065:
2064:
2035:
2034:
2001:
1954:
1938:
1931:
1927:
1918:
1914:
1904:
1902:
1898:
1887:
1879:
1878:
1874:
1858:
1854:
1847:
1843:
1835:
1831:
1820:Radio Broadcast
1814:
1813:
1809:
1792:Edwin Armstrong
1789:
1785:
1776:
1772:
1759:
1755:
1748:
1744:
1733:
1729:
1716:
1715:
1711:
1700:
1693:
1682:
1675:
1668:
1664:
1657:
1653:
1644:
1640:
1633:
1622:
1611:
1607:
1598:
1596:
1592:
1585:
1581:
1580:
1576:
1565:
1550:
1539:
1535:
1528:
1524:
1515:
1513:
1509:
1502:
1494:
1493:
1489:
1482:
1466:
1462:
1455:
1439:
1428:
1421:
1405:
1401:
1391:
1389:
1385:
1361:(9). New York:
1350:
1344:
1340:
1329:
1325:
1315:
1313:
1309:
1305:Hong, Sungook.
1303:
1299:
1292:
1276:
1269:
1258:
1257:
1244:
1233:
1229:
1220:W. L. Everitt,
1218:
1211:
1200:
1196:
1185:
1181:
1177:
1159:Audion receiver
1155:
1144:
1131:
1118:
1105:
1092:
1082:
1056:
1048:low-pass filter
1030:
1018:superheterodyne
957:superheterodyne
953:Edwin Armstrong
937:
874:superheterodyne
866:
858:single-sideband
854:
813:radiotelegraphy
806:
800:
772:
764:beat oscillator
730:
723:
722:
718:
713:
711:
708:
707:
691:
688:
687:
668:
661:
660:
656:
651:
637:
630:
629:
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609:
608:
604:
602:
599:
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582:
579:
578:
560:
559:
555:
553:
550:
549:
533:
530:
529:
513:
510:
509:
491:
490:
486:
484:
481:
480:
461:
454:
453:
449:
441:
438:
437:
421:
418:
417:
392:
389:
388:
372:
369:
368:
352:
349:
348:
314:
301:
300:
296:
294:
291:
290:
272:
271:
267:
265:
262:
261:
191:
110:Edwin Armstrong
87:Schmitt trigger
77:(also known as
24:
17:
12:
11:
5:
2073:
2063:
2062:
2057:
2052:
2047:
2033:
2032:
2026:
2017:
2012:
2000:
1999:External links
1997:
1996:
1995:
1992:
1977:
1957:
1952:
1937:
1936:
1925:
1912:
1872:
1852:
1841:
1829:
1807:
1783:
1770:
1753:
1742:
1727:
1709:
1691:
1673:
1662:
1651:
1645:E. E. Zepler,
1638:
1620:
1605:
1574:
1548:
1533:
1522:
1487:
1480:
1460:
1453:
1426:
1420:978-1463437503
1419:
1399:
1338:
1323:
1297:
1290:
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1178:
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1122:
1109:
1096:
1081:
1078:
1055:
1052:
1029:
1026:
1022:Volksempfänger
995:proximity fuze
936:
933:
865:
862:
853:
850:
802:Main article:
799:
796:
771:
768:
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737:
733:
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671:
664:
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324:
321:
317:
313:
310:
304:
299:
275:
270:
190:
187:
183:walkie-talkies
153:active filters
40:(lower center)
38:regeneration,
15:
9:
6:
4:
3:
2:
2072:
2061:
2058:
2056:
2053:
2051:
2048:
2046:
2043:
2042:
2040:
2030:
2027:
2025:
2021:
2018:
2016:
2013:
2010:
2006:
2003:
2002:
1993:
1989:
1985:
1984:
1978:
1975:
1971:
1965:
1964:
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1631:
1629:
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1618:
1616:
1609:
1595:on 2017-06-27
1591:
1584:
1578:
1571:
1570:
1563:
1561:
1559:
1557:
1555:
1553:
1546:
1544:
1537:
1531:
1526:
1512:on 2017-06-27
1508:
1501:
1499:
1491:
1483:
1477:
1473:
1472:
1464:
1456:
1450:
1446:
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1249:
1247:
1240:
1238:
1231:
1225:
1223:
1216:
1214:
1207:
1205:
1202:E. Williams,
1198:
1192:
1190:
1183:
1179:
1170:
1167:
1165:
1162:
1160:
1157:
1156:
1140:
1136:
1127:
1123:
1114:
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1101:
1097:
1088:
1084:
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1077:
1074:
1070:
1064:
1060:
1051:
1049:
1044:
1034:
1025:
1023:
1019:
1014:
1012:
1008:
1007:radio control
1004:
1003:vacuum triode
1000:
996:
992:
991:Friend or Foe
988:
983:
979:
976:
971:
969:
968:Supreme Court
964:
963:Lee De Forest
960:
958:
954:
950:
941:
932:
930:
924:
922:
917:
913:
909:
907:
903:
899:
898:keyless locks
895:
891:
890:digital radio
887:
883:
879:
875:
871:
861:
859:
852:SSB reception
849:
847:
843:
839:
834:
832:
828:
824:
823:
818:
814:
811:
805:
795:
793:
789:
785:
781:
777:
767:
765:
761:
756:
752:
738:
735:
719:
693:
657:
648:
645:
638:
626:
622:
605:
584:
556:
535:
515:
487:
466:
462:
450:
446:
443:
423:
403:
400:
397:
394:
374:
354:
331:
328:
325:
322:
315:
311:
308:
297:
268:
259:
255:
250:
248:
244:
240:
236:
232:
231:tuned circuit
228:
224:
220:
216:
212:
208:
200:
195:
186:
184:
180:
176:
172:
169:
165:
160:
158:
154:
150:
146:
142:
138:
133:
131:
127:
126:feedback loop
123:
119:
115:
111:
106:
104:
100:
96:
92:
88:
84:
80:
76:
72:
68:
60:
59:
52:
45:
41:
37:
33:
28:
22:
2028:
2019:
1987:
1981:
1973:
1962:
1943:
1928:
1920:
1915:
1903:. Retrieved
1896:the original
1882:
1875:
1855:
1844:
1839:, p. 55
1832:
1823:
1819:
1810:
1802:
1798:
1786:
1778:
1773:
1765:
1761:
1756:
1745:
1736:
1730:
1717:
1712:
1702:
1684:
1665:
1654:
1646:
1641:
1614:
1608:
1597:. Retrieved
1590:the original
1577:
1567:
1542:
1536:
1525:
1514:. Retrieved
1507:the original
1497:
1490:
1470:
1463:
1443:
1409:
1402:
1390:. Retrieved
1383:the original
1358:
1354:
1341:
1331:
1326:
1314:. Retrieved
1300:
1280:
1260:
1236:
1230:
1221:
1203:
1197:
1188:
1182:
1169:Q multiplier
1065:
1061:
1057:
1040:
1015:
1013:as a hobby.
986:
984:
980:
975:vacuum tubes
972:
961:
946:
925:
921:interference
918:
914:
910:
878:vacuum tubes
867:
855:
845:
841:
835:
830:
821:
807:
773:
770:AM reception
763:
759:
757:
753:
257:
253:
251:
242:
227:regeneration
226:
204:
171:transceivers
163:
161:
134:
118:World War II
107:
98:
90:
82:
79:regeneration
78:
66:
64:
58:variocoupler
56:
43:
39:
35:
1885:data sheet"
1365:: 215–247.
929:chaotically
908:receivers.
792:selectivity
780:oscillation
258:selectivity
254:sensitivity
211:vacuum tube
149:oscillators
2039:Categories
1953:0060981199
1849:Lewis 1991
1837:Morse 1925
1599:2018-07-04
1516:2018-07-04
1481:008047005X
1454:1847285260
1392:August 29,
1291:0080938469
1175:References
1139:US 2211091
1126:US 1424065
1113:US 1342885
1100:US 1170881
1087:US 1113149
1073:heterodyne
906:cell phone
886:transistor
827:heterodyne
817:Morse code
215:transistor
185:and toys.
1355:Proc. IRE
999:thyratron
784:bandwidth
649:−
398:−
326:−
247:loop gain
181:devices,
71:amplifier
32:shortwave
1905:20 March
1316:March 9,
1153:See also
846:autodyne
842:autodyne
804:Autodyne
239:detector
83:reaction
1868:Manpack
1379:2116636
1080:Patents
951:radio,
935:History
44:(right)
1950:
1860:German
1478:
1451:
1417:
1377:
1288:
1145:
1132:
1119:
1106:
1093:
1037:tubes.
479:where
347:where
219:op amp
155:, and
69:is an
36:(left)
1899:(PDF)
1888:(PDF)
1870:radio
1593:(PDF)
1586:(PDF)
1510:(PDF)
1503:(PDF)
1386:(PDF)
1375:S2CID
1351:(PDF)
1310:(PDF)
1148:1940.
838:mixer
217:, or
1948:ISBN
1923:p. 7
1907:2017
1476:ISBN
1449:ISBN
1415:ISBN
1394:2012
1318:2014
1286:ISBN
902:RFID
872:and
831:beat
822:beat
774:For
256:and
207:gain
205:The
103:gain
1983:QST
1972:in
1704:QST
1686:QST
1569:QST
1367:doi
870:TRF
829:or
762:or
289:is
225:or
168:IFF
137:TRF
81:or
2041::
1988:17
1986:,
1890:.
1866:=
1862::
1822:,
1818:,
1803:10
1801:,
1720:.
1694:^
1676:^
1623:^
1551:^
1429:^
1373:.
1357:.
1353:.
1270:^
1245:^
1212:^
949:FM
900:,
896:,
810:CW
776:AM
751:.
213:,
177:,
159:.
151:,
132:.
95:RF
65:A
1909:.
1881:"
1824:1
1602:.
1519:.
1484:.
1457:.
1423:.
1396:.
1369::
1359:3
1320:.
1294:.
815:(
788:Q
739:R
736:=
732:|
725:r
720:R
715:|
694:Q
674:)
670:|
663:r
658:R
653:|
646:R
643:(
639:/
632:L
627:X
623:=
617:g
614:e
611:r
606:Q
585:Q
562:r
557:R
536:R
516:R
493:L
488:X
467:R
463:/
456:L
451:X
447:=
444:Q
424:Q
404:a
401:u
395:1
375:a
355:u
335:)
332:a
329:u
323:1
320:(
316:/
312:u
309:=
303:o
298:u
274:o
269:u
122:Q
61:.
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
