Return-Path: <owner-rsgb_lf_group@blacksheep.org>
Received: from rly-mf05.mx.aol.com (rly-mf05.mail.aol.com [172.20.29.175]) by air-mf02.mail.aol.com (v120.9) with ESMTP id MAILINMF024-95d4743043d1b6; Tue, 20 Nov 2007 10:59:14 -0400
Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-mf05.mx.aol.com (v120.9) with ESMTP id MAILRELAYINMF053-95d4743043d1b6; Tue, 20 Nov 2007 10:59:01 -0400
Received: from majordom by post.thorcom.com with local (Exim 4.14)
id 1IuVSb-0001nv-Lf
for rs_out_1@blacksheep.org; Tue, 20 Nov 2007 15:56:25 +0000
Received: from [83.244.159.144] (helo=relay3.thorcom.net)
by post.thorcom.com with esmtp (Exim 4.14)
id 1IuVSX-0001nm-G7
for rsgb_lf_group@blacksheep.org; Tue, 20 Nov 2007 15:56:22 +0000
Received: from pne-smtpout1-sn2.hy.skanova.net ([81.228.8.83])
by relay3.thorcom.net with esmtp (Exim 4.63)
(envelope-from <jh.bodin@telia.com>)
id 1IuVSQ-0001pB-KM
for rsgb_lf_group@blacksheep.org; Tue, 20 Nov 2007 15:56:17 +0000
Received: from [127.0.0.1] (62.20.250.132) by pne-smtpout1-sn2.hy.skanova.net (7.3.129) (authenticated as u33233109)
id 471A56C0008BCB2F for rsgb_lf_group@blacksheep.org; Tue, 20 Nov 2007 16:55:45 +0100
Message-ID: <47430398.8000702@telia.com>
Date: Tue, 20 Nov 2007 16:56:08 +0100
From: "Johan H. Bodin" <jh.bodin@telia.com>
User-Agent: Thunderbird 2.0.0.9 (Windows/20071031)
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <000c01c82b85$97ec0010$2ee4fc3e@g3kev>
In-Reply-To: <000c01c82b85$97ec0010$2ee4fc3e@g3kev>
X-Spam-Score: 0.0 (/)
X-Spam-Report: autolearn=disabled,none
Subject: Re: LF: CLASS E
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com
X-Spam-Level:
X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.63
X-SA-Exim-Scanned: Yes
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-Listname: rsgb_lf_group
X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org
X-SA-Exim-Scanned: No; SAEximRunCond expanded to false
X-AOL-IP: 193.82.116.20
X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_helo : n
X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_822_from : n
X-Mailer: Unknown (No Version)
Mal,
for proper class E operation, the drain waveform must be allowed to be
non-symmetrical so you cannot just use a center tapped output transformer. In
other words, there must be no "hard coupling" between the drains in a class E
push-pull amplifier. One way is to design two identical class E amplifiers, each
designed for an output power P into the load R. Note: Each amplifier must have
its own DC feeding choke - no center tapped stuff here! Then feed these two
amplifiers with push-pull drive (180 degrees phase shift) and connect the
primary winding of an output transformer between the outputs of the two
amplifiers. The output transformer should be designed so that 2*R will be "seen"
when "looking" into the primary. The total output power will be 2*P. With
sufficient Q in the series tanks (C2, L), the output current will be almost
sinusoidal, as in the single ended case, so the two halves of the amplifier will
not "know" that they are actually operating in push-pull. Since the two series
resonant tanks of the two amplifiers and the output transformer primary will all
be connected in series, you can simplify the circuit by using a single resonant
tank with twice the L and half the C. This may look assymetrical but it gives
exactly the same result (a few pF stray C can be neglected at these low
frequencies...). One can say that this is simply two class E amplifiers
connected in series. However, the even harmonic cancelling property of push-pull
is still there because of circuit (and drive) symmetry.
I have tried this configuration, for example on 160m QRP, and it seems to work
very well.
73
Johan SM6LKM
hamilton mal skrev:
> Hi all
> Is anyone else using a class E PA on 500 or 137. Mine is single ended, maybe
> someone has a push pull design.
> 73 de Mal/G3KEV
>
>
>