Phase preselector. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / radio reception
Comments on the article
UB5UG proposes to increase the input selectivity of the radio receiver by the phase method. To do this, a long line, short-circuited at the end, must be connected to the input of the receiver. Connect the taps from it to the inputs of the differential amplifier, which is the first stage of the receiver (Fig. 1). A standing wave forms in the line. The voltage phases in neighboring half-waves of a standing wave differ by 180°.
If the distance between the taps is 0,5 lX(2n-1), where n is the number of half-waves, then when the frequency changes, the phase difference in the taps increases n times faster than in the case of removing a signal from neighboring voltage maxima, and therefore, n times the selectivity of the preselector is increased.
To reduce the physical length of the line, you should use a coaxial cable that has a spiral inner core.
Author: UB5UG; Publication: N. Bolshakov, rf.atnn.ru
See other articles Section radio reception.
Read and write useful comments on this article.
<< Back
Latest news of science and technology, new electronics:
Artificial leather for touch emulation
15.04.2024
In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>
Petgugu Global cat litter
15.04.2024
Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>
The attractiveness of caring men
14.04.2024
The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>
| Random news from the Archive Kitchen salt asteroid
14.06.2023
The Americans carefully studied a sample of the near-Earth asteroid Itokawa and found crystals of ordinary kitchen salt here, which could not have appeared without the presence of water.
Even 13 years ago, the Japanese spacecraft Hayabusa delivered the first ever rock samples from an asteroid to Earth. This space rock turned out to be the near-Earth asteroid Itokawa, which is approximately 610 meters wide. And all these years, scientists from different countries continue to carefully study these samples. Specialists from the University of Arizona, USA, found crystals of ordinary kitchen salt in the composition of the asteroid, which could not have appeared if there was no water nearby. This again changes the idea of how water could get to our planet.
Scientists continue to search for answers to questions about how complex life on Earth arose. The fact that they were able to find crystals of sodium chloride or ordinary kitchen salt in the composition of the Itokawa asteroid, which could only form in the presence of water, indicates that asteroids played an important role both in the process of its appearance on Earth and in the origin of life.
Currently, scientists believe that the asteroid Itokawa, which flies relatively close to Earth (at a distance of several million kilometers from us), was part of a larger space rock, but then broke away from it. And the rock sample brought from the asteroid is a chondrite, which is a type of meteorite that is part of a rocky asteroid.
According to American scientists, they did not expect to find crystals of sodium chloride, since such asteroids do not suggest the presence of water-bearing minerals.
The authors of the study point out that for a long time it was believed that chondrites, that is, meteorites falling to Earth from rocky asteroids, could not bring water to the planet. But a new discovery suggests that such asteroids likely contain much more water than previously thought.
Naturally, the experts were very surprised by their discovery and were initially skeptical about the results. After all, a sample from the Itokawa asteroid could have been contaminated with other substances, falling to Earth. But a careful study showed that the crystals of ordinary salt belong to the asteroid Itokawa.
The sodium-rich silicate mineral plagioclase was also found in the meteorite. And this mineral was also formed under the influence of water. Therefore, the researchers believe that this proves the fact that the asteroid Itokawa probably contains or contained a lot of water in the past.
The Itokawa asteroid is one of the most common S-type asteroids in the solar system. Therefore, it is assumed that the theory of the origin of water with the help of asteroids that fell to the Earth or meteorites that broke away from them is becoming more and more plausible.
|
Other interesting news:
▪ Sleepless night adds fat
▪ Image processing module with native deep learning neural network
▪ Mitsubishi Electric 60" Projection Video Wall Display VS-60HS12U Slim Cube
▪ Ocean floor cleaning robots
▪ Microscopic tunable lasers
News feed of science and technology, new electronics
Interesting materials of the Free Technical Library:
▪ site section Chargers, accumulators, batteries. Article selection
▪ article At an unnamed height. Popular expression
▪ article What is a tack? Detailed answer
▪ Article Dentist. Job description
▪ article Heating beehives. Encyclopedia of radio electronics and electrical engineering
▪ article A simple 50 MHz band transverter. Encyclopedia of radio electronics and electrical engineering
Leave your comment on this article:
All languages of this page
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua
2000-2024
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese