Electronic Projects, forums and more.

Go Back   Electronic Circuits Projects Diagrams Free > Electronic Content > Electronic Theory


Electronic Theory Basic principles, ideas, concepts, laws, and formulas behind electronics.

Reply
 
Tools
Old 16th October 2008, 07:37 PM   #16
Default

Sure you can, need to save a copy, the original can't be edited without the acrobat writer(what ever is named now).

-BaC
Quote:
Originally Posted by Space Varmint View Post
By Golly I cannot save them. That sucks!
__________________
Error[888] "while trying to load":[reality.sh] kernel: [Panic!]...{Universe has been Modified!}...
BaCaRdi is offline  
Old 16th October 2008, 07:42 PM   #17
Default

Ouch..know all about that!
just replace your mother with my ex-wife:P

no wrath like...you know the rest

Being a network engineer you could imagine all I have lost, in designs alone. Yep the computer an my laptop went with the rest of my stuff, written and digital storage alike.

-BaC
Quote:
Originally Posted by Space Varmint View Post
By Golly I cannot save them. That sucks!

You wanna hear one of the great tragedies of my life...I took a 1 & 1/2 year correspondence course from Nat'l Radio Institute before I went back to school. It had a huge section on "Attenuators,Equalizers & Filters". This thing showed you how to break down a filter where you could analyze every arm & leg impedance in a complex latter network. I had my books stored at my folks house and neglected to pick them up a couple of years. Well they decided to remodel the basement and it was only one or two small boxes, and instead of calling me, they just took it upon themselves to throw my books in the garbage. Heart breaking story. I still love them though.
__________________
Error[888] "while trying to load":[reality.sh] kernel: [Panic!]...{Universe has been Modified!}...
BaCaRdi is offline  
Old 5th January 2009, 08:47 AM   #18
Default

Similar to what Space Varmint states...

Q = ω L / R = (1/r)(√L/C); where ω = ωo = cut off frequency

I.E. a RATIO of reactance to resistance.

A way to visualize it is...a cut off intensity of a slope; or how "drastic" the cut off slope is.
Similar to what Space Varmint states...

Q = ω L / R = (1/r)(√L/C); where ω = ωo = cut off frequency

I.E. a RATIO of reactance to resistance.

A way to visualize it is...a cut off intensity of a slope; or how "drastic" the cut off slope is.
__________________
Kule is Chinese
Kule is the SEO manager for www.totobay.com.
kulela is offline  
Old 7th January 2009, 11:18 AM   #19
Default

Quote:
Originally Posted by mneary View Post
To measure SNR, terminate the input with no signal, and measure the output. This is the noise. Then apply a signal. This is the signal. The ratio (20 log(Vn/Vs)) is SNR.

This does not take distortion into account which would be SINAD.
Thats a good way of mesuring signal to noise. but the equation is the other way round (20 log(Vn/Vs)) will give you the noise to signal ratio. (20 log(Vs/Vn)) will give you signal to noise.

Sorry if im being a bit pedantic.
owenpauljames is offline  
Old 7th January 2009, 04:34 PM   #20
Default

Quote:
Originally Posted by owenpauljames View Post
Thats a good way of mesuring signal to noise. but the equation is the other way round (20 log(Vn/Vs)) will give you the noise to signal ratio. (20 log(Vs/Vn)) will give you signal to noise.

Sorry if im being a bit pedantic.
That is pretty interesting. Although the philosophy for receiver performance has changed over the years. I do well remember the famous signal to noise spec. You hardly see it anymore. Now days the term is "dynamic range". It has been found that the single most important circuit or stage of a receiver is the receiver's first mixer. This is where you want to take care. After that, just make everything clean clean clean and if your first mixer is working right. You got a receiver!

I will attempt to sum up briefly what dynamic rage refers to. Though the mixer is used in conjunction with the local oscillator to select a particular frequency, what is actually happening is the entire band of frequency is in the mixer all at once. So when we speak "signal/noise" it may be the opposite result you are really trying to achieve. Because attempt to over amplify a signal, you are in effect amplifying the entire band of frequencies. That means that Joe's alligator station down the street will be amplified too. You do not want that because Joe's alligator station will over drive the mixer causing it to go into an over driven distortion mode where everything in the band inside the mixer will be modulated by his station. So now we have the modulation of the selected signal modulated by our friend Joe. This is the infamous spec IMD (intermodulation distortion). All ports in that first mixer are important. But you can now see that S/N can be very undesirable at times. Also a good post mixer amp will have allot of effect. You do not want any reflected or standing wave products coming back into the mixer for reprocessing.
Space Varmint is offline  
Old 7th January 2009, 04:50 PM   #21
Default

Quote:
Originally Posted by kulela View Post
Similar to what Space Varmint states...

Q = ω L / R = (1/r)(√L/C); where ω = ωo = cut off frequency

I.E. a RATIO of reactance to resistance.

A way to visualize it is...a cut off intensity of a slope; or how "drastic" the cut off slope is.
Similar to what Space Varmint states...

Q = ω L / R = (1/r)(√L/C); where ω = ωo = cut off frequency

I.E. a RATIO of reactance to resistance.

A way to visualize it is...a cut off intensity of a slope; or how "drastic" the cut off slope is.
It's funny what the term "Q" stands for, Quality Factor. Because sometimes we may desire a low Q, but does that mean it is low quality when it is the desired out come? Some applications for low Q would be in a PLL synthesizer when we want a broad range of frequencies or bandwidth. If the Q is high it will severely limit the bandwidth. It can be broadened by physically adding a resistor to the VCO's tank circuit thereby lower the Q as seen in kulela's formula. The other factor in limiting bandwidth will be the design of the low pass or "loop filter". Noise limiters will also degrade bandwidth. Some of the right kind of noise is desirable.
Space Varmint is offline  
Old 8th January 2009, 02:23 PM   #22
Default

Quote:
Originally Posted by Space Varmint View Post
That is pretty interesting. Although the philosophy for receiver performance has changed over the years. I do well remember the famous signal to noise spec. You hardly see it anymore. Now days the term is "dynamic range". It has been found that the single most important circuit or stage of a receiver is the receiver's first mixer. This is where you want to take care. After that, just make everything clean clean clean and if your first mixer is working right. You got a receiver!

I will attempt to sum up briefly what dynamic rage refers to. Though the mixer is used in conjunction with the local oscillator to select a particular frequency, what is actually happening is the entire band of frequency is in the mixer all at once. So when we speak "signal/noise" it may be the opposite result you are really trying to achieve. Because attempt to over amplify a signal, you are in effect amplifying the entire band of frequencies. That means that Joe's alligator station down the street will be amplified too. You do not want that because Joe's alligator station will over drive the mixer causing it to go into an over driven distortion mode where everything in the band inside the mixer will be modulated by his station. So now we have the modulation of the selected signal modulated by our friend Joe. This is the infamous spec IMD (intermodulation distortion). All ports in that first mixer are important. But you can now see that S/N can be very undesirable at times. Also a good post mixer amp will have allot of effect. You do not want any reflected or standing wave products coming back into the mixer for reprocessing.
Why are you talking about Radio?

The original question was
"4)if i have an Op-amp based filter, how do i calculate its SNR?"

I was just helping clarify a question. Is ulot even making a radio filter?
owenpauljames is offline  
Reply

Tags
electronic, terms

Thread Tools
Display Modes


Similar
Title Starter Forum Replies Latest
electronic help plz evan_ellerbe Electronic Projects Design/Ideas/Reviews 6 28th November 2007 07:09 PM
Electronic Tag ryans63 Electronic Projects Design/Ideas/Reviews 3 2nd November 2007 03:48 AM
Hello, I'm new to Electronic circuits, how do I get info. on electronic tach for m.c. pwotoole General Electronics Chat 17 16th May 2007 06:33 AM
Soldering terms ques kentken General Electronics Chat 5 5th July 2004 07:13 AM
audio electronic mixer & electronic voice substitute kartel Electronic Projects Design/Ideas/Reviews 0 7th November 2003 03:39 AM



All times are GMT. The time now is 02:22 AM.


Electronic Circuits  |  Learning Electronics
eXTReMe Tracker