Rob Judd wrote:
The ARRL Handbook (any edition).

On its way here...

The Art of Electronics.

I have this one and im not too happy with oscillator chapter. However, this
is still one of the best books i've seen.

Regards
Tom

On Sat, 19 Jul 2003 06:47:32 -0700, W7TI wrote:

On Sat, 19 Jul 2003 12:42:02 +0100, Paul Burridge
wrote:

0 hz is hardly a 'frequency.'

__________________________________________________ _______

Of course zero Hz is a frequency. Have you ever had a checkbook balance
of zero? Is that not a balance? :-)


Frequently!!! :-)


--
Ken Knox
N1JRO


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On Sat, 19 Jul 2003 06:47:32 -0700, W7TI wrote:

On Sat, 19 Jul 2003 12:42:02 +0100, Paul Burridge
wrote:

0 hz is hardly a 'frequency.'

__________________________________________________ _______

Of course zero Hz is a frequency. Have you ever had a checkbook balance
of zero? Is that not a balance? :-)


Frequently!!! :-)


--
Ken Knox
N1JRO


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 80,000 Newsgroups - 16 Different Servers! =-----

A perfectly symmetrical square wave doesn't contain any even harmonics.
For best results when using this technique to generate even harmonics,
the square wave needs to have a longer "on" period than "off" period or
vice-versa.

Roy Lewallen, W7EL

Paul Burridge wrote:

Feed the square output to a coil+capacitor in parallel and you'll get
a sine wave. Tune the this 'tank' circuit for harmonics of the
funamental and you can double, triple, quadruple and so on the
original square wave's frequency.

A perfectly symmetrical square wave doesn't contain any even harmonics.
For best results when using this technique to generate even harmonics,
the square wave needs to have a longer "on" period than "off" period or
vice-versa.

Roy Lewallen, W7EL

Paul Burridge wrote:

Feed the square output to a coil+capacitor in parallel and you'll get
a sine wave. Tune the this 'tank' circuit for harmonics of the
funamental and you can double, triple, quadruple and so on the
original square wave's frequency.

"Tom" wrote in message
...
Paul Burridge wrote:
Feed the square output to a coil+capacitor in parallel and you'll get
a sine wave. Tune the this 'tank' circuit for harmonics of the
funamental and you can double, triple, quadruple and so on the
original square wave's frequency.

Thank you Paul! This is a good hint. Can you tell me in which book did you
learn it? I would really like to get into this stuff.

IMO you are being led astray. I don't see why the emphasis on frequency
multiplication. It is fairly simple to make an LC oscillator cover a 2 to 1
frequency range, or even 3 to 1. That could mean 4 to 12 MHz in one tuning
range and 1.3 to 4 in another. The problem is lower frequencies. These days
it is hard to find a large-enough variable capacitor for operation down in
the few-hundreds of kilohertz range, let alone lower.

I know of only two ways that will cover the whole zero to 12 MHz range
without bandswitching or switched filters.

One is the direct digital synthesizer DDS. Single chip DDS units are
available [Analog Devices Inc] fairly cheaply, but they are tiny and require
a computer or equivalent to control them. You get "perfect" frequency
accuracy and stability and a sine-wave output.

The other is a beat-frequency method with two oscillators operating
considerably above 12 MHz. One crystal controlled, the other knob
controlled tuning from the crystal frequency to 12 MHz higher. Feed them
into a double-balanced mixer (MiniCircuits) followed by a low-pass filter
that passes 0 to 12 MHz, and strongly rejects the crystal osc frequency and
all higher. One knob, no switching, no computer needed for control - but
also much poorer frequency accuracy and stability.

"Tom" wrote in message
...
Paul Burridge wrote:
Feed the square output to a coil+capacitor in parallel and you'll get
a sine wave. Tune the this 'tank' circuit for harmonics of the
funamental and you can double, triple, quadruple and so on the
original square wave's frequency.

Thank you Paul! This is a good hint. Can you tell me in which book did you
learn it? I would really like to get into this stuff.

IMO you are being led astray. I don't see why the emphasis on frequency
multiplication. It is fairly simple to make an LC oscillator cover a 2 to 1
frequency range, or even 3 to 1. That could mean 4 to 12 MHz in one tuning
range and 1.3 to 4 in another. The problem is lower frequencies. These days
it is hard to find a large-enough variable capacitor for operation down in
the few-hundreds of kilohertz range, let alone lower.

I know of only two ways that will cover the whole zero to 12 MHz range
without bandswitching or switched filters.

One is the direct digital synthesizer DDS. Single chip DDS units are
available [Analog Devices Inc] fairly cheaply, but they are tiny and require
a computer or equivalent to control them. You get "perfect" frequency
accuracy and stability and a sine-wave output.

The other is a beat-frequency method with two oscillators operating
considerably above 12 MHz. One crystal controlled, the other knob
controlled tuning from the crystal frequency to 12 MHz higher. Feed them
into a double-balanced mixer (MiniCircuits) followed by a low-pass filter
that passes 0 to 12 MHz, and strongly rejects the crystal osc frequency and
all higher. One knob, no switching, no computer needed for control - but
also much poorer frequency accuracy and stability.

"Leigh W3NLB" wrote in message
...
On Thu, 17 Jul 2003 19:11:57 +0200, "Tom" wrote:

Hello

If anyone can recommend me a good book from which i will learn to construct
oscillator that for example covers range 0-12 MHz.

Thanks in advance!
Tom


12 MHz is easy. 0 MHz is really difficult.


I have a couple of those.
They put out significant power.

--

... Hank

Hank: http://horedson.home.att.net
W0RLI: http://w0rli.home.att.net

"Leigh W3NLB" wrote in message
...
On Thu, 17 Jul 2003 19:11:57 +0200, "Tom" wrote:

Hello

If anyone can recommend me a good book from which i will learn to construct
oscillator that for example covers range 0-12 MHz.

Thanks in advance!
Tom


12 MHz is easy. 0 MHz is really difficult.


I have a couple of those.
They put out significant power.

--

... Hank

Hank: http://horedson.home.att.net
W0RLI: http://w0rli.home.att.net

On Sat, 19 Jul 2003 17:39:23 GMT, John Popelish
wrote:

Paul Burridge wrote:

Feed the square output to a coil+capacitor in parallel and you'll get
a sine wave. Tune the this 'tank' circuit for harmonics of the
funamental and you can double, triple, quadruple and so on the
original square wave's frequency.

This works pretty good at the third and fifth harmonics, but there is
no second or fourth harmonic in a perfect square wave.

Good point, John. But fortunately, I've never generated a *perfect*
square wave! :-) In practice, it's probably more accurate to say that
the even harmonics are well down on the odds. Blame it on dv/dt.