Regeneration Effect

Regeneration EffectRegeneration effect, discovered shortly after the invention of the first radio tube, triode, was truly a revolution in radio engineering of those times.The sharp increase in sensitivity of receivers and, consequently, a sharp increase in radio coverage at the same transmitter input power, make it possible to attract many people's (especially radio enthusiasts's) attention to radio. Simple single-tube transceivers in those times of the 20th-30th allowed amateurs to keep in touch with the whole world. More "serious" receiving devices containing one or two UHF lamps and one lamp in the regenerative stage, such as the famous "Cube-4", were considered to be complex professional models.Regenerative receiver is a receiver of direct amplification with an adjustable positive feedback. It is the positive feedback that increases the equivalent quality factor of the L1C2 circuit, what is equivalent to an increase in the input signal amplitude. Due to the fact that as the quality factor increases the bandwidth of the circuit reduces, efficient isolation of a narrowband signal, such as a voice or a telegraph message, becomes possible. When using a regenerator in the LW-MW range, you can notice that when it comes to generation, i.e. to the optimal reception mode, due to increasing of the Q-factor of the circuit the upper frequencies of the transmission are cut off, which leads to the impaired transmission of the broadcast stations. In the MW-LW range the bandwidth that actually could be reached in AM mode - 3...6 kHz, and it is clearly not enough for good transmission of broadcast stations.With stable transmission in the range of 3...10 MHz the bandwidth of the receiver is 10 ... 15 kHz, in the range of 10...20 MHz it reaches 30 kHz at its upper edge, and increases even more in the ranges above 20 MHz. This shows that it may be used to transmit AM stations only in the lower SW ranges.It seemed that regenerator will never lose their positions. And only the second world war ended the triumph of the regenerator, which in those days was used in some military radio stations of the USSR and other warring countries. This device was undermined by some of its peculiar flaws, which made it impossible to be used in the wartime, i.e., in the time, when the number of the stations on air was high. And after the war it was used only by amateurs, and as the time passed it was used more and more rarely. But the way the regenerator has made, and the role it played in the development of radio, do not let us leave it behind. And maybe its major drawbacks will be improved soon, and it will make another contribution to the radio communication technologies.

Category:

Science & Technology

Tags:

• effect
• power
• radio
• receiver
• transmitter
• vacuum tube