Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 [2] 3 Next   Go Down
  Print  
Author Topic: what exactly *IS* CW... and how are there sidebands?  (Read 7372 times)
STAYVERTICAL
Member

Posts: 875




Ignore
« Reply #15 on: August 29, 2012, 03:12:55 AM »

Bob,

Gaining an understanding of Fourier analysis will lead to real understanding.
This is equivalent to teaching a man to fish, rather than giving him a fish.

You can explain how a CW waveform has sidebands, but what about PSK31, or SSB, or FSK.....

This is why I always look at directing people to more general concepts and techniques.

I had a friend who worked for a company which repaired certain electronic equipment.
He was a guy who refused to learn the basics.
Day after day, he would come to me and ask me how a different circuit worked, so he could fix it.
I tried to teach him fundamental electronics, but he was not motivated to do so, and eventually lost that job.
Without those basics, every new circuit diagram was foreign to him.

My technique of learning anything is to learn the fundamentals first, and then you can understand the implementation easily.

This is why I suggest learning, or at least playing with FFT's.
It is like explaining how phase shift occurs in capacitors for example.
You could try explaining it by talking about charge building up and so on, or you could just use differential calculus.
For example,  the rate of change of voltage determines the current flow.
So if you apply a sine wave sin(theta) to a capacitor, the first derivative (rate of change), of Sin(theta) is Cos(theta) - a 90 degree change.

Not only does it simply and elegantly explain the phase difference, but it can also be applied to other waveforms.
This is why I suggest general means of understanding electronics - rather than special cases.
It is easier, more complete, and teaches the concept without making it a one off case.

We all learn differently, but I am by no means a math wizard - so if I can do it, anyone can.
Oh, and if you learn everything in that book I suggested, you will certainly be very competent in DSP techniques.

I guess, in the end, we are all different, and learn differently as well.
So whether we use empirical, mathematical or voodoo techniques to learn is not important or better - as long as we reach understanding.

73 - Rob
« Last Edit: August 29, 2012, 03:57:11 AM by STAYVERTICAL » Logged
PA0BLAH
Member

Posts: 0




Ignore
« Reply #16 on: August 29, 2012, 04:06:40 AM »

Bob,

Gaining an understanding of Fourier analysis will lead to real understanding.

Mwah, all those integral transformations are nothing else than expanding the signal in a sum of terms of an infinite set of orthogonal functions. Why Fourier, that does it with a set of sine waves sin(nwt+fie(n)) as terms with n a natural number of zero to infinite. You can do it with an infinite orthogonal set of Walsh functions, they are binary, better for the understanding of digital signals. I handled once an Antenna problem with the expansion in an orthogonal set of Bessel functions.

When you do it by FFT you have to sample the signal first, and that makes the spectrum infinite wide, so your FFT is actually repetitive. Fancy windows like Hannah have to be introduced to mask the introduced errors.

Do it then with the Z-transform, that maps the left half plane of the complex plane to the inner of a circle, and projects the infinite number you generate by sampling  exactly over each other in the Z-plane.
Quote

This is equivalent to teaching a man to fish, rather than giving him a fish.

You have to give him a fish in order not to bring him in starvation, during your teaching

Quote
You can explain how a CW waveform has sidebands, but what about PSK31, or SSB, or FSK.....
No problem. FSK is just the sum of the AM spectra of 2 transmitters the frequency shift apart, that are keyed a "baud"time different in time. So when the one is on the other is off.

PSK31 is a 2 tone signal, with the smallest possible bandwidth. Phase modulation with 180 degree difference between mark and space, hence also the spectrum of 2 AM transmitters keyed on and off, however on the same frequency and with carriers 180 degrees out of phase.

You don't need FFT when you just take simple signals, like the carrier is cos(wt) and the audio is cos(ut) for DSB suppressed carrier,  or (1+cos(ut)) for AM. Multiply them and look at the result. cos(a)cos(b)=0.5[cos(a+b)+cos(a-b)] Just  math from school learned when I was 15, just before I was forced to drop out, because I challenged the teachers with poisoned questions.

Rob, You have to go to sleep right now when you live somewhere in Australia.

Bob
« Last Edit: August 29, 2012, 04:12:38 AM by PA0BLAH » Logged
STAYVERTICAL
Member

Posts: 875




Ignore
« Reply #17 on: August 29, 2012, 04:25:36 AM »

Bob,

I am glad you finally see the utility of mathematical techniques.
If it is good enough for you, it should be good enough for others.
I feel I have achieved something there.

No, I never need much sleep.
I work on a 24 hour sliding sleep cycle.
I am a fan of the late Buckminster Fuller, who pioneered this technique.
His wife finally made him give it up, because she could not take him sleeping and being awake all around the clock.
But I don't have that problem, so expect me to post anytime around the clock.

As regards leaving school at 15 because of poisonous questioning of your teachers - I am astounded at that.
There is nothing in your numerous posts to indicate that personality trait.

On to the next joust I guess.

73 - Rob
Logged
PA0BLAH
Member

Posts: 0




Ignore
« Reply #18 on: August 29, 2012, 05:38:39 AM »

Bob,

I am glad you finally see the utility of mathematical techniques.

That is not finally Rob, I see that very well, where the brain fails to make complex logic steps, math is the tool, and where the brain is too slow, the computer is the  tool. All programmed (math AND the computer) by the slow brain formulating simple axioms and stepstoning on them .  But I think somebody with quite another job then mathematics and electronics involved, has not to get the lesson that sounds: "First your math, and after that you can enjoy your hobby".

I am glad to hear that a ham that just got his general, is questioning about how and what, so I think it is best to show him in a way he hopefully can understand, how and what.

Forums here have the severe and overwhelming  disadvantage, and are due to that in effect worthless, because everybody that want to show himself (like a rooster) tells his kukelekuu (dutch rooster) his quoquelicot (french rooster) nothing to say as : here is the sperm gland, come to me hopefully you evaluate at the long term to a PA0BLAH alike. (Passing on the route Stayvertical-alike hahaha)

Quote

If it is good enough for you, it should be good enough for others.
I feel I have achieved something there.

Pity that you are so far away, we could be closed friends.
Insulting each other at the utmost, not being hurt.

What in fact is insulting?
When I say you are a lousy snake, you will be not be insulted, because you know you are not a lousy snake.

So people can't insult me, when they try, because I know they are wrong.

However when you are a rooster with only air and feathers trying to impress the environment, I can insult you by saying you are only a rooster with nothing as air and feathers to show and impress the environment.

I saw you editted your msg, before I replied. So you don't exactly write, finally, what you thought at the moment of writing, that is a pity. But I read it as first published before the edit. So I appreciate your personality more before then after the edit.

Was it not you that opened my eyes when you  said persons learn different? You are a retired professional teacher in adult courses in Australia, I suppose. Well I hate teachers, I am at least 5 times faster learning from a book. May be infinite, because I never learned something aural from a teacher. It must be an extreme handicap when you can only learn something in conversation with a teacher. That handicapped persons were your gratefully students.

BoB

Logged
STAYVERTICAL
Member

Posts: 875




Ignore
« Reply #19 on: August 29, 2012, 06:10:05 AM »

I am glad we could be friends Bob,
Yes, I changed my first edit, because, in the end, I did not want to be too hurtful.
It is not the first time I have done that, and frankly I misread your comments.
I learned many years ago, that not admitting a mistake is just piling error upon error.

It is sometimes difficult to infer your meaning, although I do respect your skills in english.
So sometimes it takes a few readings to get to the core of what you are saying.

People who cannot admit to being wrong, are doomed to a life of misery.
In the end, what we express here are opinions.
They are not facts which we brought into existence - they are merely facts we have learned from others who came before.

Where we can be truly creative is in explaining things to others in ways which help them to learn.
You obviously have a wide range of technical skills, and it would be a pity to waste them by clothing them in a cloak of sarcasm.

Belittling people is not helping them, and appears more like bullying than elmering.
And I will let the statement about teaching handicapped people pass, but say it is in very poor taste.
A society is judged by how it treats those who are weakest within it, and is a gauge of compassion.

You have much to offer those of us who need the skills you have gained in your lifetime.
But the price should not be ridicule and poisonous posts.

I, for one, would be very interested in seeing your knowledge used to elmer people who could use your skills.
But, perhaps you could leave the sarcasm and ridicule out of the equation, since this only turns off the lights, not lights the way.

73 Friend Bob,

- Rob


Logged
AK4YA
Member

Posts: 106




Ignore
« Reply #20 on: August 29, 2012, 06:58:05 AM »

<SNIP>
In the time domain, we see square waves, pure and simple - nothing more complicated.
But if you look in the frequency domain, we see a series of sine waves of different amplitudes.
<SNIP>
73 - Rob
EURIKA of course.  this is where my disconnect was.  I always read and knew that a square wave was the sum of a carrier and its odd harmonics, I just never put 2 and 2 together to understand the big picture.

My next goal is to understand how the sidebands and carrier are demodulated in a BFO type of receiver, specifically, wouldnt faster morse code transmissions have a higher pitch than slower ones, since they are demodulated with a product betector/BFO, just like SSB is demodulated?
« Last Edit: August 29, 2012, 07:24:33 AM by KC5VNN » Logged
PA0BLAH
Member

Posts: 0




Ignore
« Reply #21 on: August 29, 2012, 08:21:00 AM »


People who cannot admit to being wrong, are doomed to a life of misery.

The priests and ayatollahs of different tasting churches will not be happy with this statement. But they,  in name of their supreme,  forgive you when you are willful to join their only true church. It remembers me of the photoshopped away expensive watch, forgetting the accompanying glance of the mirror image in the table surface,  of the leader of some church.

Quote
In the end, what we express here are opinions.
They are not facts which we brought into existence - they are merely facts we have learned from others who came before.
Where we can be truly creative is in explaining things to others in ways which help them to learn.

Of course you will in order to be able to be proud of your skills and your former profession, and you have obviously skills, which I conclude reading the last post op topic starter, but realise that not those learned facts are the basis of our present world, but the creative brains, that created the manmade world as you see it around you, based on the scientific facts that are presented and understood.

Quote
You obviously have a wide range of technical skills, and it would be a pity to waste them by clothing them in a cloak of sarcasm.

I didn't waste them, certainly not, but my professional environment were always people of around the same or higher level, (because I am pretty stupid) so when you are retired, you fall back in a world of roosters, and that give some reaction, as noticed by you. A long lasting reaction, that is true, because I left my profession longer ago then I worked in it.


Quote
Belittling people is not helping them, and appears more like bullying than elmering.

I do not see that. When a guy asks me how much is  2^10, I say : 1024 decimal or  are your numbers hexadecimal? In that case is the answer 65536 decimal, SUCKER. Ask me again when they are octal based.

So he knows I find him a sucker, AND he knows the correct answer on his question.

It is the price he pays me for being lazy and not to find out for himself without questioning on a forum, and the answer is for free. May be it encourages the next time to find out for himself.


Quote
And I will let the statement about teaching handicapped people pass, but say it is in very poor taste.
A society is judged by how it treats those who are weakest within it, and is a gauge of compassion.

Come to Holland, There was a time that we passed the amount one million inhabitants having benefits from  the law of the too disabled to work.  And we have about 6 million people in the age able to work, so one out of 6 is disabled.

Bob

« Last Edit: August 29, 2012, 08:28:40 AM by PA0BLAH » Logged
K8AXW
Member

Posts: 3905




Ignore
« Reply #22 on: August 29, 2012, 10:19:06 AM »

STAYVERTICAL:

Quote
Where we can be truly creative is in explaining things to others in ways which help them to learn.
You obviously have a wide range of technical skills, and it would be a pity to waste them by clothing them in a cloak of sarcasm.

Belittling people is not helping them, and appears more like bullying than elmering.
And I will let the statement about teaching handicapped people pass, but say it is in very poor taste.
A society is judged by how it treats those who are weakest within it, and is a gauge of compassion.

You have much to offer those of us who need the skills you have gained in your lifetime.
But the price should not be ridicule and poisonous posts.

I, for one, would be very interested in seeing your knowledge used to elmer people who could use your skills.
But, perhaps you could leave the sarcasm and ridicule out of the equation, since this only turns off the lights, not lights the way.

73 Friend Bob,

- Rob



Very well written Rob! 

PA0BLAH:  I've followed your many posts here on this thread and see that you're a very well educated (school or self taught - Irrelevant) man with excellent English skills.  Yet you prefer to act as you do which serves no purpose except to alienate people.  There's no damned excuse for doing this and your reasoning for doing so simply doesn't fly!
Logged
K7KBN
Member

Posts: 2814




Ignore
« Reply #23 on: August 29, 2012, 12:11:06 PM »

<SNIP>
In the time domain, we see square waves, pure and simple - nothing more complicated.
But if you look in the frequency domain, we see a series of sine waves of different amplitudes.
<SNIP>
73 - Rob
EURIKA of course.  this is where my disconnect was.  I always read and knew that a square wave was the sum of a carrier and its odd harmonics, I just never put 2 and 2 together to understand the big picture.

My next goal is to understand how the sidebands and carrier are demodulated in a BFO type of receiver, specifically, wouldnt faster morse code transmissions have a higher pitch than slower ones, since they are demodulated with a product betector/BFO, just like SSB is demodulated?

The frequency of the RF signal being received doesn't change.  If your receiver is stable and receiving a signal at 14007.38 KHz, AND if the sending station operator doesn't bump his frequency control, AND if you don't bump your tuning or BFO controls, the tone of the dits and dahs won't change, whether the sending station is keying at 5WPM and then increases to 50WPM.

Now, if one station is in a very fast aircraft, you might be able to detect some doppler ...
Logged

73
Pat K7KBN
CWO4 USNR Ret.
PA0BLAH
Member

Posts: 0




Ignore
« Reply #24 on: August 29, 2012, 12:39:19 PM »



PA0BLAH:  I've followed your many posts here on this thread and see that you're a very well educated (school or self taught - Irrelevant) man with excellent English skills.  Yet you prefer to act as you do which serves no purpose except to alienate people.  There's no damned excuse for doing this and your reasoning for doing so simply doesn't fly!

Al,  you are without doubt a nice guy, a guy to drink a glass of beer and to talk about our past life, but when you use your computer you have to behave yourself the way the "stupid" computer likes, just touch the right keys in the right sequence and the computer does what you want him (must be a him nor a her)   to do. I am the computer and you did not touch the right keys in the right sequence. That's all. But not the slightest problem, so try to insult me or push me in heaven (with 7 times 7 virgins) , doesn't make any difference in handling your msgs.
 
Sometimes I think:"Why do I explicit and only communicate in CW in the hambands?" I am starting to understand that better since I am writing in the CW chapter of this forum.

Bob
Logged
PA0BLAH
Member

Posts: 0




Ignore
« Reply #25 on: August 29, 2012, 01:03:41 PM »


My next goal is to understand how the sidebands and carrier are demodulated in a BFO type of receiver, specifically, wouldnt faster morse code transmissions have a higher pitch than slower ones, since they are demodulated with a product betector/BFO, just like SSB is demodulated?

The BFO and the CW carrier difference in frequency give you the desired tone. Say 600 Hz. The mixing process if pure multiplying 2 signals, is linear, that means the whole CW spectrum, including his sidebands, are transformed to 600 Hz audio and the 2 sidebands look for the on off keying of the 600 Hz audio. So faster CW with more space between its sidebands yields faster 600 Hz switching because the 600 Hz has wider spread sidebands.

Stayvertical (who is right now laying horizontal) can translate it in understandable language, when you can't understand  this.

In earlier times (in Dutch: Vroegah)  they detected with a BFO and a diode detector. Then however the strongest signal is the carrier, and that may be a QRM signal. So product detection is surely better.

BoB
( You know the joke of Brigitte Bardot with on her left and right buttock a B , her initials,  tattooed?)
Logged
STAYVERTICAL
Member

Posts: 875




Ignore
« Reply #26 on: August 29, 2012, 01:52:32 PM »

Bob,

I am sorry to see that you refuse to do anything except cause dissent.
Your gaining of knowledge is like a fine meal, prepared meticulously, and then dumping a bucket of mustard on top.

Knowledge is only useful if it is transferred to others, or used to improve your own life.

I understand that you see yourself as a liberator of those oppressed by inflated roosters.
Unfortunately, it appears that you are like the legendary ghost ship, the Flying Dutchman, doomed to sail the seas forever in your quest.

However, despite your frequent rages against various religions, I will have to take the advice of one.
Paraphrasing, it goes something like "If your teaching is not accepted, shake the dust off your shoes as you leave".

This thread has been hijacked long enough, and in fairness to the original poster, I will retire from the ring.

I am certain, you will have enough in this post to write a three page scornful post about it, so enjoy yourself.
It appears that you are on a personal crusade against shadows from your past - and I wish you well in your campaign.

73 - Rob
« Last Edit: August 29, 2012, 02:18:36 PM by STAYVERTICAL » Logged
PA0BLAH
Member

Posts: 0




Ignore
« Reply #27 on: August 29, 2012, 03:45:14 PM »

Bob,

Your gaining of knowledge is like a fine meal, prepared meticulously, and then dumping a bucket of mustard on top.

Actually this remembers me on the situation in a fine food French restaurant (don't use the toilet facilities) of an American guy eating only with a fork, left hand under the table, that drops half a bottle of tomato ketchup on his served exclusive fine meal.

Quote
Knowledge is only useful if it is transferred to others, or used to improve your own life.

I understand that you see yourself as a liberator of those oppressed by inflated roosters.
Unfortunately, it appears that you are like the legendary ghost ship, the Flying Dutchman, doomed to sail the seas forever in your quest.

Amazing that other people that know nothing about me, and write that they are  not believing what I write, such as being ham for 65 years, living in Holland, and pounding only the brass, write that they think they know more then I write.
Quote
However, despite your frequent rages against various religions,
I only reacted on your statement that people that wouldn't admit their wrong thinking are destined to live in misery, something like that. And because there are a large number of religions, and splitting offs, and all say they are the whole and only sole truth, I only can conclude with the knowledge I share now and here, and sharing that is the value of knowledge as you just said, that at least all of them minus one must be wrong. They know that, must be,  do not admit that fact, and still dont live in misery, as I adstructed with a recent example.

They call this kind of reasoning "Mathematical Logic" (in order to distinguish if from "Female Logic" I suppose)

Quote
Paraphrasing, it goes something like "If your teaching is not accepted, shake the dust off your shoes as you leave".

May be that statement is valid when you try to teach an opinion, or religion,  hence indoctrination, not when you teach the unchanging laws of nature and all her consequences.
 
Quote
This thread has been hijacked long enough, and in fairness to the original poster, I will retire from the ring.
Well Topic starter got his answers, I guarantee they are correct, and I am not going to another forum chapter, in order to meet the no code appliance Cb-ers overthere with their alfa bravo  chit chat.
Quote
I am certain, you will have enough in this post to write a three page scornful post about it, so enjoy yourself.
It appears that you are on a personal crusade against shadows from your past - and I wish you well in your campaign.
No not at all. I am just reading and answering if it suits me.
CUL Rob best 73 Bob

73 - Rob
[/quote]
« Last Edit: August 29, 2012, 04:26:12 PM by PA0BLAH » Logged
K8AXW
Member

Posts: 3905




Ignore
« Reply #28 on: August 30, 2012, 09:07:49 AM »

PA0BLAH:

Yes, I am a nice guy to drink a beer with.  I've drank beer with many people, including Dutch and former enemies in Germany.  However, I would never knowingly drink a beer with you.  I socialize only with people I respect.  After seeing that you are capable of holding a serious and intelligent conversation and then go back to your insulting ways, I have no respect for you.

As for my computer ..."but when you use your computer you have to behave yourself the way the "stupid" computer likes, just touch the right keys in the right sequence and the computer does what you want him (must be a him nor a her)   to do. I am the computer and you did not touch the right keys in the right sequence."

I don't know what that means.  I can tell you that one use of my computer here on eHam is to try to help others, not insult or demean them.  As STAYVERITCAL says, it's a shame when you have such great knowledge but don't use it to help but instead to insult. (Paraphrased)

You make many nasty references to CB operators Bob but you are exactly the same! You use a "handle" (PA0BLAH) which is not a government issued callsign and probably a fake name (Bob) to hide behind so you can spread your hate and poison without anyone knowing who you really are.  Or is it because down deep you feel some shame?

I'm sure you will answer this so please when you do, give it your best shot.  This will be my last to you.  AR VA CL

Logged
PA0BLAH
Member

Posts: 0




Ignore
« Reply #29 on: August 30, 2012, 10:05:22 AM »

PA0BLAH:

Yes, I am a nice guy to drink a beer with.  I've drank beer with many people, including Dutch and former enemies in Germany.


Just as Overste Karremans (some superhigh military rank) with his shy dog-eyes and martial mustache , commander of "Dutch bat" that drank a beer with Mladic, while 8000 males were separated from their family and executed in Sebrenica?

Quote
However, I would never knowingly drink a beer with you.  I socialize only with people I respect.  After seeing that you are capable of holding a serious and intelligent conversation and then go back to your insulting ways, I have no respect for you.

That is your fundamental right Al. No problem, only for yourself, because it turns out you can not handle people that are different in the way  you expect them to be, and  above that they refuse to be bended in the way you want them to be, in order to like them. They call that different "personalities", I suppose. Not everybody in the world can be a person respected by you, but don't forget: your respect is a time variant behavior when you drink a beer with former enemies, as you said.  

It must be comfortable to have no talents, then you can't waste them anyway. So those people  have always a position to stimulate other people to be envy on them. 40 year in an 8 hour shift copying Morse number stations, retirement benefits and that's it.

Quote
As for my computer ..."but when you use your computer you have to behave yourself the way the "stupid" computer likes, just touch the right keys in the right sequence and the computer does what you want him (must be a him nor a her)   to do. I am the computer and you did not touch the right keys in the right sequence."

I don't know what that means.

Quite simple Al, When you (try to) kick me under the ass, like you tried a few times, you just get it back. No problem no bad feelings whatsoever.

I actually enjoy myself with the primitive completely forcastable  results of my injected messages on this forum. People are obviously non linear systems. When you kick them they react on the expected way,  when you kick them twice as hard the result is not double the kicking force and additional when you give a number of kicks, spread in time,  the result is not the sum of the time-shifted time functions of each kick.  So thanks Al for proofing that. Have you any objection to show up in an article, with your call and QRZ published data, handling this kind of behavior? (no reaction is understood as no objection) Stay vertical can explain you that you are  a time variant non linear system to be described as a set of non linear differential equations with non constant coefficients . (When he has understood the over simplified book he advices to read in order to become  a DSP expert, hi)

Bob


 
« Last Edit: August 30, 2012, 10:39:37 AM by PA0BLAH » Logged
Pages: Prev 1 [2] 3 Next   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!