Variable Square Wave to Sine Wave

Two, with all due respect to my learned colleague, instead the of ARRL
handbook, try

Experimental Methods in Radio Frequency Design, by Campbell, and
Hayward, its more geared to modern, simple, home made gear then the
ARRL handbook is , sadly...

I've just had a look at amazon.co.uk (not available) then amazon.com.

4 Used available from _$498.97_ (up to $937.87).


It would need to be good at that price!


Nial.


Try Abe or other used bookstore.

On Tue, 9 Mar 2010 13:30:21 -0000, "Nial Stewart"
nial*REMOVE_THIS*@nialstewartdevelopments.co.uk> wrote:

Two, with all due respect to my learned colleague, instead the of ARRL
handbook, try

Experimental Methods in Radio Frequency Design, by Campbell, and
Hayward, its more geared to modern, simple, home made gear then the
ARRL handbook is , sadly...
I've just had a look at amazon.co.uk (not available) then amazon.com.

4 Used available from _$498.97_ (up to $937.87).


It would need to be good at that price!


Nial.


It seems to be available at ARRL for $49.99:
http://www.arrl.org/catalog/?category=Circuit+Design#9239
....so...if you want fresh oats, get them at the front of the horse...

Hiya folks. I've been interested in trying to build myself a radio
receiver for various bands, primarily as a learning experience. The
thing is, though, I've heard that it's kind of hard to build a stable
VFO above 50mhz. One of the bands I'd eventually like to receive is 2
meters (144-148mhz). Might be fun to receive television audio, as
well. Not to mention, standard FM.

Since I'm more familiar with digital electronic components rather than
analog, I've seen that there are programmable frequency oscillator
ICs, which can be set via a microcontroller. This sounds like an easy
solution for tuning, and would open the door to setting station
presets and the like as well. The problem is, I'm fairly sure that
these would output a square wave.

I've read about how you can basically use a low-pass filter to tune
out harmonics of a square wave and get a sine wave output. But from
the way I understand it, an RC filter would just filter out a specific
frequency, defeating the purpose of the variable oscillator.

So that's pretty much my question: How does one turn a variable
square wave into a sine wave?

Or, alternatively, what are more reliable ways to produce higher
frequency sine waves to begin with? Though I'm still interested in
the former question as well, for curiosity's sake.

Thanks!

- Jeff

One, google "softrock radio"

Two, with all due respect to my learned colleague, instead the of ARRL
handbook, try

Experimental Methods in Radio Frequency Design, by Campbell, and
Hayward, its more geared to modern, simple, home made gear then the
ARRL handbook is , sadly...

then look at
http://www.kangaus.com/2m_converter.htm

then
http://www.pongrance.com/

the old kit

Steve

Two, with all due respect to my learned colleague, instead the of ARRL
handbook, try

Experimental Methods in Radio Frequency Design, by Campbell, and
Hayward, its more geared to modern, simple, home made gear then the
ARRL handbook is , sadly...

I've just had a look at amazon.co.uk (not available) then amazon.com.

4 Used available from _$498.97_ (up to $937.87).

It would need to be good at that price!

Nial.