Class-D RF PA
 

Google does not turn up much when searching for the above.

I wonder if anyone can point me to any on-line references.

Specifically interested in HF circuit designs using switching FET's.

Tnx.

--
Philip de Cadenet G4ZOW

Philip de Cadenet wrote:
Google does not turn up much when searching for the above.

I wonder if anyone can point me to any on-line references.

Specifically interested in HF circuit designs using switching FET's.

Tnx.

Look for class E. Class D describes an amplifier that switches faster
than the signal and has the output filtered to pass DC. Class E
describes an amplifier that switches _at_ the signal rate and has a
filter that has finite impedance at the fundamental and infinite
impedance at all the odd harmonics. The result is that the output
transistor drives a square-wave voltage and sees a sinusoidal current,
so all the power goes to the output with none wasted.

There have been articles in QEX and even QST -- they even explain what I
just said in sufficient detail to understand it.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Hello Tim,

Look for class E. Class D describes an amplifier that switches faster
than the signal and has the output filtered to pass DC. Class E
describes an amplifier that switches _at_ the signal rate and has a
filter that has finite impedance at the fundamental and infinite
impedance at all the odd harmonics. The result is that the output
transistor drives a square-wave voltage and sees a sinusoidal current,
so all the power goes to the output with none wasted.

There have been articles in QEX and even QST -- they even explain what
I just said in sufficient detail to understand it.


Thanks for the information and article links.

I have some articles fromm Sokal and Raab on E. Also familiar with Steve
Coultier's class-E web site.

I have a QEX/QST compilation CD somewhere.

Do you have any month/year references to hand?

Tnx

--
Philip de Cadenet G4ZOW

Philip de Cadenet wrote:

Hello Tim,

Look for class E. Class D describes an amplifier that switches faster
than the signal and has the output filtered to pass DC. Class E
describes an amplifier that switches _at_ the signal rate and has a
filter that has finite impedance at the fundamental and infinite
impedance at all the odd harmonics. The result is that the output
transistor drives a square-wave voltage and sees a sinusoidal current,
so all the power goes to the output with none wasted.

There have been articles in QEX and even QST -- they even explain what
I just said in sufficient detail to understand it.


Thanks for the information and article links.

I have some articles fromm Sokal and Raab on E. Also familiar with Steve
Coultier's class-E web site.

I have a QEX/QST compilation CD somewhere.

Do you have any month/year references to hand?

Tnx

No, but I've only been reading them for 15 years -- that should narrow
things down a bit.

Sorry (for the lack of info, if not the smartass answer).

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Philip de Cadenet wrote:

Google does not turn up much when searching for the above.

I wonder if anyone can point me to any on-line references.

Specifically interested in HF circuit designs using switching FET's.

Tnx.

Class E . Start with these:
http://www.classeradio.com/
http://www.geocities.com/k3xf/Classe.html

/Ake
If you have a big e-mail box I can send some articles.
--
Remove "extra" in my e-mail

Hello Ake, and others who have responded directly

Class E . Start with these:
http://www.classeradio.com/
http://www.geocities.com/k3xf/Classe.html

/Ake
If you have a big e-mail box I can send some articles.

I'm familier with Steve Couliers class-E site.

The 40m amp was interesting.

Please feel free to mail me any other articles you have to hand.

Many thanks.
--
Philip de Cadenet G4ZOW