Return-Path: Received: (qmail 27847 invoked from network); 28 Jan 2002 18:59:16 -0000 Received: from unknown (HELO warrior.services.quay.plus.net) (212.159.14.227) by excalibur-qfe1-smtp-plusnet.harl.plus.net with SMTP; 28 Jan 2002 18:59:16 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 23577 invoked from network); 28 Jan 2002 18:59:16 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior.services.quay.plus.net with SMTP; 28 Jan 2002 18:59:16 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 16VGw2-0000GQ-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 28 Jan 2002 18:55:18 +0000 Received: from imo-m03.mx.aol.com ([64.12.136.6]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 16VGvy-0000GD-00 for rsgb_lf_group@blacksheep.org; Mon, 28 Jan 2002 18:55:14 +0000 Received: from DL4YHF@aol.com by imo-m03.mx.aol.com (mail_out_v31_r1.26.) id l.146.889313b (4249) for ; Mon, 28 Jan 2002 13:54:05 -0500 (EST) From: DL4YHF@aol.com Message-ID: <146.889313b.2986f84c@aol.com> Date: Mon, 28 Jan 2002 13:54:04 EST Subject: LF: Re: PSK31 modulation (was: Jason Tests / PSK31) To: rsgb_lf_group@blacksheep.org MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 X-Mailer: AOL 6.0 for Windows XP DE sub 50 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Content-transfer-encoding: 8bit Hello David, Jim and group,

As G0MRF wrote:
> With half the supply rail (lets say 6 Volts) on the pin, the RF output is zero.
> As the voltage is increased towards 12V the output increases in proportion.
> If the voltage is decreased from 6V towards zero then the RF output also increases
> in proportion, but with the opposite phase.

> So 6V = no output.
> > 6 V = phase 0 degrees
> < 6V = -180 degrees

Thanks for the explanation David. I have already sent Jim the information about a new 'two channel' output for PSKxx (implemented in Spectrum Lab) which uses the soundcard for this:
Left channel = Standard PSK signal with phase modulation and envelope shaping
Right channel = On/Off-keyed "audio carrier", ON for 180°, OFF for 0°
The AF carrier is required because the soundcard's output is not "DC" coupled.

I hope with two rectifier diodes and a simple lowpass filter, these signals are sufficient to drive Jim's transmitter for PSK31 with amplitude shaping. If not, the program could be easily adapted to produce different audio amplitudes similiar to the scheme you described.
So, if someone wants to try this with the SM6LKM/G0MRF DDS board just ask for an update.

> A potentially good idea when we designed it, but lacking an application.

Maybe there's an application soon.

73 Wolf DL4YHF.