On Sat, 13 Mar 2004 11:50:12 +0000, Paul Burridge
posted this:


I have at least one suggestion, but I need to know whether to send an
LTspice netlist or a gif.

Send 'em both!

I'm still working on an LTspice version of a varactor multiplier using
the base-emitter junction of a class C amp as the varactor. Basically using an
"idler" tank or tanks to augment the fifth harmonic.

The other idea is to make a doubler and a trippler fed from the
fundamental and then feed them into a mixer to get the fifth. If the doubler
and trippler are active (class C) stages, you should get as many db out at the
higher frequency as you put in at the fundamental. The mixer can have gain too.
Three transistors, three tuned circuits, and Bob's yer uncle.

Jim

On Sun, 14 Mar 2004 19:51:50 GMT, James Meyer
wrote:

On Sat, 13 Mar 2004 11:50:12 +0000, Paul Burridge
posted this:


I have at least one suggestion, but I need to know whether to send an
LTspice netlist or a gif.

Send 'em both!

I'm still working on an LTspice version of a varactor multiplier using
the base-emitter junction of a class C amp as the varactor. Basically using an
"idler" tank or tanks to augment the fifth harmonic.

The other idea is to make a doubler and a trippler fed from the
fundamental and then feed them into a mixer to get the fifth. If the doubler
and trippler are active (class C) stages, you should get as many db out at the
higher frequency as you put in at the fundamental. The mixer can have gain too.
Three transistors, three tuned circuits, and Bob's yer uncle.

Jim


Why not just bandpass filter the 5th from the square wave? Too simple?


John

On Sun, 14 Mar 2004 12:04:18 -0800, John Larkin
wrote:


Why not just bandpass filter the 5th from the square wave? Too simple?

I suggested this a while ago, but no one seemed very keen on that
solution for some reason. Pity, as it does seem to Spice very well. A
5/6V TTL level square wave winds up as around .5 of a volt of 5th
harmonic, post-filtering. Not bad!
--

The BBC: Licensed at public expense to spread lies.

On Sun, 14 Mar 2004 21:27:21 +0000, Paul Burridge
wrote:

On Sun, 14 Mar 2004 12:04:18 -0800, John Larkin
wrote:


Why not just bandpass filter the 5th from the square wave? Too simple?

I suggested this a while ago, but no one seemed very keen on that
solution for some reason.

Write down their names for me please, so I can remember to not hire
them.

John

I read in sci.electronics.design that John Larkin jjlarkin@highSNIPland
THIStechPLEASEnology.com wrote (in qvrb50hvn0t1nj7kq5cako00bjrtis7nnr@
4ax.com) about 'Extracting the 5th Harmonic', on Mon, 15 Mar 2004:
On Sun, 14 Mar 2004 21:27:21 +0000, Paul Burridge
wrote:

On Sun, 14 Mar 2004 12:04:18 -0800, John Larkin
wrote:


Why not just bandpass filter the 5th from the square wave? Too simple?

I suggested this a while ago, but no one seemed very keen on that
solution for some reason.

Write down their names for me please, so I can remember to not hire
them.

The reason no-one seemed keen is that the OP's **complaint** was that
his 5th harmonic BP filter didn't produce any output.

I think we have to supplement 'Read The Fascinating Manual' with 'RTCT'
- 'Read The Copulating Thread'.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

On Mon, 15 Mar 2004 19:05:02 +0000, John Woodgate
wrote:

I read in sci.electronics.design that John Larkin jjlarkin@highSNIPland
THIStechPLEASEnology.com wrote (in qvrb50hvn0t1nj7kq5cako00bjrtis7nnr@
4ax.com) about 'Extracting the 5th Harmonic', on Mon, 15 Mar 2004:
On Sun, 14 Mar 2004 21:27:21 +0000, Paul Burridge
wrote:

On Sun, 14 Mar 2004 12:04:18 -0800, John Larkin
m wrote:


Why not just bandpass filter the 5th from the square wave? Too simple?

I suggested this a while ago, but no one seemed very keen on that
solution for some reason.

Write down their names for me please, so I can remember to not hire
them.

The reason no-one seemed keen is that the OP's **complaint** was that
his 5th harmonic BP filter didn't produce any output.


So I guess Fourier was wrong; makes sense, with a French name like
that. Somebody in this group also proved Shannon to be wrong... does
anybody remember who?

John

I read in sci.electronics.design that John Larkin jjlarkin@highSNIPland
THIStechPLEASEnology.com wrote (in lr1c50ls8v4stqisn34rcd8eoc4bkqu4vo@
4ax.com) about 'Extracting the 5th Harmonic', on Mon, 15 Mar 2004:
spam.yuk wrote:

I read in sci.electronics.design that John Larkin jjlarkin@highSNIPland
THIStechPLEASEnology.com wrote (in qvrb50hvn0t1nj7kq5cako00bjrtis7nnr@
4ax.com) about 'Extracting the 5th Harmonic', on Mon, 15 Mar 2004:
On Sun, 14 Mar 2004 21:27:21 +0000, Paul Burridge
wrote:

On Sun, 14 Mar 2004 12:04:18 -0800, John Larkin
wrote:


Why not just bandpass filter the 5th from the square wave? Too simple?

I suggested this a while ago, but no one seemed very keen on that
solution for some reason.

Write down their names for me please, so I can remember to not hire
them.

The reason no-one seemed keen is that the OP's **complaint** was that
his 5th harmonic BP filter didn't produce any output.


So I guess Fourier was wrong; makes sense, with a French name like that.

No, what has emerged from the discussion is that rather small deviations
from a perfect square waveform can drastically reduce the amount of one
or more harmonics in the spectrum, and this probably is the source of
the problem.

--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I read in sci.electronics.design that John Larkin jjlarkin@highSNIPland
THIStechPLEASEnology.com wrote (in lr1c50ls8v4stqisn34rcd8eoc4bkqu4vo@
4ax.com) about 'Extracting the 5th Harmonic', on Mon, 15 Mar 2004:
spam.yuk wrote:

I read in sci.electronics.design that John Larkin jjlarkin@highSNIPland
THIStechPLEASEnology.com wrote (in qvrb50hvn0t1nj7kq5cako00bjrtis7nnr@
4ax.com) about 'Extracting the 5th Harmonic', on Mon, 15 Mar 2004:
On Sun, 14 Mar 2004 21:27:21 +0000, Paul Burridge
wrote:

On Sun, 14 Mar 2004 12:04:18 -0800, John Larkin
wrote:


Why not just bandpass filter the 5th from the square wave? Too simple?

I suggested this a while ago, but no one seemed very keen on that
solution for some reason.

Write down their names for me please, so I can remember to not hire
them.

The reason no-one seemed keen is that the OP's **complaint** was that
his 5th harmonic BP filter didn't produce any output.


So I guess Fourier was wrong; makes sense, with a French name like that.

No, what has emerged from the discussion is that rather small deviations
from a perfect square waveform can drastically reduce the amount of one
or more harmonics in the spectrum, and this probably is the source of
the problem.

--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

On Mon, 15 Mar 2004 19:05:02 +0000, John Woodgate
wrote:

The reason no-one seemed keen is that the OP's **complaint** was that
his 5th harmonic BP filter didn't produce any output.

Eh?? Where did you get that from? I haven't even tried filtering yet!
I still haven't exhausted all the other suggestions made during the
course of this thread.

I think we have to supplement 'Read The Fascinating Manual' with 'RTCT'
- 'Read The Copulating Thread'.

Perhaps you should...
--

The BBC: Licensed at public expense to spread lies.

On Mon, 15 Mar 2004 23:00:49 +0000, Paul Burridge
wrote:

On Mon, 15 Mar 2004 19:05:02 +0000, John Woodgate
wrote:

The reason no-one seemed keen is that the OP's **complaint** was that
his 5th harmonic BP filter didn't produce any output.

Eh?? Where did you get that from? I haven't even tried filtering yet!
I still haven't exhausted all the other suggestions made during the
course of this thread.

---
What???

According to your schematic, the input to R1 is a 2.16MHz square wave
and L1VC1 is a parallel tuned tank, (filter) tuned to 10.8MHz. So is
L2VC2C7. If you're not trying to do any filtering, what are those tanks
doing in there?

--
John Fields