Hazeltine's prototype Neutrodyne receiver, presented at a March 2, 1923 meeting of the Radio Society of America at Columbia University. It had two stages of tuned radio frequency amplification. (closeup, bottom) The three interstage coupling coils, from which the neutralizing signal is taken, are visible.
The Neutrodyne radio receiver, invented in 1922 by Louis Hazeltine, was a particular type of tuned radio frequency (TRF) receiver, in which the instability-causing inter-electrode capacitance of the triode RF tubes is cancelled out or "neutralized"[1][2] to prevent parasitic oscillations which caused "squealing" or "howling" noises in the speakers of early radio sets. In most designs, a small extra winding on each of the RF amplifiers' tuned anode coils was used to generate a small antiphase signal, which could be adjusted by special variable trim capacitors to cancel out the stray signal coupled to the grid via plate-to-grid capacitance. The Neutrodyne circuit was popular in radio receivers until the 1930s, when it was superseded by the superheterodyne receiver.
^US Patent No. 1450080, Louis Alan Hazeltine, "Method and electric circuit arrangement for neutralizing capacity coupling"; filed August 7, 1919; granted March 27, 1923
^Hazeltine, Louis A. (March 1923). "Tuned Radio Frequency Amplification With Neutralization of Capacity Coupling" (PDF). Proc. of the Radio Club of America. 2 (8). New York: Radio Club of America: 7–12. Retrieved March 7, 2014.[permanent dead link]
The Neutrodyne radio receiver, invented in 1922 by Louis Hazeltine, was a particular type of tuned radio frequency (TRF) receiver, in which the instability-causing...
capacitance between the plate and grid in early triodes. This was solved by the Neutrodyne circuit, and later the development of the tetrode and pentode around 1930...
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the Neutrodyne receiver Martin Mason Hazeltine (1827–1903), American photographer Hazeltine Corporation, the company which marketed the Neutrodyne and...
1886 – May 24, 1964) was an engineer and physicist, the inventor of the Neutrodyne circuit, and the Hazeltine-Fremodyne Superregenerative circuit. He was...
the interelectrode capacitance. Neutralization was used in the popular Neutrodyne series of TRF receivers. Under certain conditions, "the neutralization...
capacitance. This technique was employed and led to the success of the Neutrodyne radio during the 1920s. However, neutralization required careful adjustment...
Hazeltine, M.E., Sc. D., 1926, founder Hazeltine Corporation, inventor of the neutrodyne radio receiver Augustus Moore Herring, aviation pioneer Peter Cooper Hewitt...
frequencies in a manner that competed favorably with the less robust neutrodyne TRF receiver. Higher IF frequencies (455 kHz was a common standard) came...
within the passband of the amplifying device. A classic example is the Neutrodyne circuit used in tuned radio frequency receivers. June 2009 Washington...
media related to Reflex receiver circuits. Schematic of FADA model 160 neutrodyne radio, a reflectional receiver from the 1920s. Schematic of General Electric...
Hazeltine, after discovering that they had independently invented the Neutrodyne receiver. (It entered large-scale production in 1923, and was the dominant...
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