Signal to Noise Ratio, Noise Temperature and Noise Figure

Подписаться 16 тыс.

Просмотров 6 тыс.

50% 1

Learn more about SNR, Noise Measurements and its use cases:
keysig.ht/otuWWh
Gregory explains the implication on noise degradation on amplifiers chains, what is Signal to Noise Ratio, how to calculate noise in terms of Noise Temperatures and what is Noise Figure.
Support the channel, becoming a Patron:
/ allelectronics

Наука

Опубликовано:

29 июл 2023

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 34

@AllElectronicsChannel 11 месяцев назад

Support the channel becoming a Patron patreon.com/allelectronics

@tdhoward 2 месяца назад

Excellent explanations!

@RideGasGas 11 месяцев назад

Glad you added the example of satellite communications at the end of the video. Have been working in satellite communications for 45+ years and noise figure is really important for this application. In my first job working on an Army satcom terminal receiving in the 7.25-7.75 GHz range, the AN/MSC-46. The antenna used a cryogenically cooled parametric amplifier where the first stage was operated at about 17 kelvin to reduce thermal noise. Low noise amplifiers have improved considerably since then. The systems I work on these days operate in the Ka band (17.7-20.2 GHz and 27.5-30 GHz) and as you noted the antenna temperature depends where it is pointed and also the size of the aperture to some degree. If the antenna on the Earth and is pointed to space it will see primarily the cold sky plus a small amount of the Earth noise coming from side lobe gain, say 40 K. If the antenna is on the satellite and the entire 3 dB beamwidth is pointed onto the Earth, then the antenna temperature will be around 290 K. If the satellite antenna is pointed to the edge of the Earth and only a part of the beam covers the Earth then the antenna temperature will be something less than 290 K. In the Ka band, a reasonably good satellite receiving system noise temperature is around 650 K after the noise from the LNA is added to the antenna noise, and often more like 1100 K given the additional losses of complex feed systems in front of the LNA.

@AllElectronicsChannel 10 месяцев назад

That's amazing... I would spend hours talking too you... so much things to learn.. I'm fascinated about all this stuff. I hope some day I have the opportunity to work on this area. I also have interest to try making a parametric amp. Thank you for your comment!

@RideGasGas 10 месяцев назад

@@AllElectronicsChannel I very much enjoy the way you tackle the subjects you cover, starting with a fundamental math analysis and a hands-on build to show the principles. I did a quick Google search and did find article which seems to describe something very similar to the system I worked on. apps.dtic.mil/sti/tr/pdf/AD0751652.pdf In the case of the MSC 46 system, it used a varactor diode being pumped at 42 GHz. The power output of the 42 GHz source and the diode bias were adjusted to tune the gain and frequency response of the amplifier's first stage. The second stage of the amplifier was actually heated to a stable temperature above room temp and tuning for gain and flatness across the band of the two stages that interacted with each other was quite tricky. Today's LNAs that offer super low noise at room temperatures made all of the above expensive bulky and temperamental gear obsolete within a few years after I worked on the gear. But I'm really glad I had the chance to learn and work on the gear, not many people can say they've rebuilt a cryogenic amplifier working at 17 K :-)

@AllElectronicsChannel 10 месяцев назад

I will study it!! Thanks man...

@andersonnobre5163 10 месяцев назад

@@AllElectronicsChannel do

@j.w.8663 18 дней назад

I will be using pyramidal horn antennas with an LNA and a spectrum analyzer to scan in a 360 degree azimuth to look for possible interference in the X and S bands (2GHz and 8GHz). One of the requirements is to "Calculate cold sky noise temperature at 10 degree elevation." Would you (or anyone) perhaps know how one does this? Is this simply measurable somehow? Google doesn't get me too far...😕

@rudylopez6546 4 месяца назад

This was a phenomenal explanation on noise figure!!! Your videos are always a pleasure to learn from. Keep up the great work!

@se2702 8 месяцев назад

Very good presentation with just the right amount of math. Thanks!

@andersonnobre5163 10 месяцев назад

Thank you dear friend Eng. Greg! I have got learned telecom in your Y T Channel. GOD blesses you !

@AllElectronicsChannel 10 месяцев назад

Wonderful!

@matsbengtsson3756 11 месяцев назад

Well done. Keep up the detailed and good information. Thank you.

@parassah2376 10 месяцев назад

Great video form Nepal

@AllElectronicsChannel 10 месяцев назад

🙏🏼🙏🏼

@ibancardona5220 11 месяцев назад

Thanks! 73, from EB3FRN

@AllElectronicsChannel 11 месяцев назад

You're welcome!

@gilvantexasgil4246 8 месяцев назад

Muito bom. Estou assistindo na velocidade 0.5 pra da tempo ver tradução e observar a explicação.

@AllElectronicsChannel 8 месяцев назад

Welcome 🙏🏼🙏🏼

@Look_who_is_talking 11 месяцев назад

Could u please suggest best books for Digital elrctronics and Analog electronics for beginners ...

@AllElectronicsChannel 10 месяцев назад

I will make a video about!

@xx-mz2eg Месяц назад

Hi, sorry but I still do not have clear idea what noise temperature is. So is it defined for amplifier or antenna out of blue or it depends on physical temperature? How to measure it?

@AllElectronicsChannel Месяц назад

The noise temperature is the temperature a resistor would need to be at, for generating the same amount of noise power that a circuit generates.

@j.w.8663 Месяц назад

I'm a bit confused here: for the antenna temperature do you mean the temperature that the antenna is itself; - or do you mean the temperature of where it's pointing i.e. the sky or the horizon...at 24:25 you say it's the temp of the antenna itself, then at 25:12 you say looking at sky it's different...?

@copernicofelinis 11 месяцев назад

Noice. I mean, nice. 😊

@AllElectronicsChannel 10 месяцев назад

Thanks! 😄

@comment8767 11 месяцев назад

"use" is a one-sylable word... "received" is a two-sylable word...not three... "preserved" has two ...etc. Great video... I only mention the English because you are close to being perfect with English delivery except for this small issue.

@AllElectronicsChannel 11 месяцев назад

Thank you for loving the channe and for the help! 🤩🤩

@comment8767 11 месяцев назад

:defined" ... two syllable.... deee-fined ... not de-fine-ed Same goes for amplified. No amplifi-ed. If you just took off the -ed and pasted a t on the end, it would be closer.

@comment8767 11 месяцев назад

You pronounce "referred" correctly .... you do NOT say re-fer-ed..... The other words I mentioned merely need to be pronounced in the same way....

@comment8767 11 месяцев назад

"fix-ed" ... should be one syllable. Americans actually say "fixt" .... they make the 'ed' sound like a t. I am not sure what British do.

@comment8767 11 месяцев назад

"de-gre-dade-ing" .... Americans would say dee-grade-ing. There is a difference in pronunciation between "degradation" versus ""degrading" and "degrade". There is no logical reason for it .... just the way native speakers say it ...