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Schematic of an early autodyne receiver.
The autodyne circuit was an improvement to radio signal amplification using the De Forest Audion vacuum tube amplifier. By allowing the tube to oscillate at a frequency slightly different from the desired signal, the sensitivity over other receivers was greatly improved.[1] The autodyne circuit was invented by Edwin Howard Armstrong of Columbia University, New York, NY.[citation needed] He inserted a tuned circuit in the output circuit of the Audion vacuum tube amplifier.[citation needed] By adjusting the tuning of this tuned circuit, Armstrong was able to dramatically increase the gain of the Audion amplifier. Further increase in tuning resulted in the Audion amplifier reaching self-oscillation.
This oscillating receiver circuit meant that the then latest technology continuous wave (CW) transmissions could be demodulated. Previously only spark, interrupted continuous wave (ICW, signals which were produced by a motor chopping or turning the signal on and off at an audio rate), or modulated continuous wave (MCW), could produce intelligible output from a receiver.
When the autodyne oscillator was advanced to self-oscillation, continuous wave Morse code dots and dashes would be clearly heard from the headphones as short or long periods of sound of a particular tone, instead of an all but impossible to decode series of thumps. Spark and chopped CW (ICW) were amplitude modulated signals which didn't require an oscillating detector.
Such a regenerative circuit is capable of receiving weak signals, if carefully coupled to an antenna. Antenna coupling interacts with tuning, making optimum adjustments difficult.
The autodyne circuit was an improvement to radio signal amplification using the De Forest Audion vacuum tube amplifier. By allowing the tube to oscillate...
device as oscillator and mixer simultaneously, is known as autodyne reception. The term autodyne predates multigrid tubes and is not applied to use of tubes...
ratio (SNR) by up to 3dB. Early Autodyne receivers typically used IFs of only 150 kHz or so. As a consequence, most Autodyne receivers required greater front-end...
make CW radiotelegraphy transmissions audible. This mode was called an autodyne receiver. To receive radiotelegraphy, the feedback was increased until...
Retrieved 2019-09-02. Grammer, George (January 1933). "Rationalizing the Autodyne". QST. XVII (1). West Hartford, CN: American Radio Relay, Inc.: 11. Retrieved...
Known for Armstrong oscillator Armstrong Tower Armstrong phase modulator Autodyne FM broadcasting FM radio Frequency modulation Regenerative circuit Superheterodyne...
oscillator connected to an antenna; it functioned as both a transmitter and an autodyne detector (receiver). When the target was far away, little of the oscillator's...
oscillator, but the same valve doubled as the oscillator. This was known as the autodyne mixer. Early examples had difficulty oscillating across the frequency range...
Electrical Engineering at Columbia University. He had sold his patents for the autodyne (regenerative circuit) and frequency modulation to Westinghouse, which...
of octal type 5V4G. 15 – Sharp-cutoff pentode, used in farm radios, in autodyne circuits requiring a separate cathode. 48 – Power tetrode, used in 32-volt...
Retrieved October 12, 2015. Grammer, George (January 1933). "Rationalizing the Autodyne". QST. The 7000- and 14,000-kc. grid coils are wound with No. 18 enameled...
Interplanetary Plasma (Patent of the Republic of Bulgaria No 45821). Short-Range Autodyne System (Patent of the Republic of Bulgaria No 45520). Short-Range Radar...
Fritz Hochreuter Rudy Bartling Rainer Brezinka Porsche 911S 189 17 GTO 48 Autodyne Luis Sereix Lyn St. James Phil Currin Chevrolet Corvette 186 18 GTU 01...
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