Return-Path: Received: (qmail 13109 invoked from network); 30 Oct 2002 18:39:35 -0000 Received: from marstons.services.quay.plus.net (212.159.14.223) by mailstore with SMTP; 30 Oct 2002 18:39:35 -0000 Received: (qmail 3384 invoked by uid 10001); 30 Oct 2002 19:42:39 -0000 Received: from post.thorcom.com (193.82.116.70) by marstons.services.quay.plus.net with SMTP; 30 Oct 2002 19:42:39 -0000 Received: from majordom by post.thorcom.com with local (Exim 4.10) id 186xi6-0004y3-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 30 Oct 2002 18:36:58 +0000 Received: from [212.1.130.1] (helo=smtp-1.visp.telinco.net) by post.thorcom.com with esmtp (Exim 4.10) id 186xi5-0004xu-00 for rsgb_lf_group@blacksheep.org; Wed, 30 Oct 2002 18:36:57 +0000 Received: from [212.1.140.11] (helo=RSGB613192) by smtp-1.visp.telinco.net with smtp (Exim 3.32 #1) id 186xcX-0002zQ-00 for rsgb_lf_group@blacksheep.org; Wed, 30 Oct 2002 18:31:14 +0000 Message-ID: <002b01c28043$53e25060$045bfea9@RSGB613192> From: "Andy talbot" To: rsgb_lf_group@blacksheep.org References: <78.2f74dacc.2af16f83@aol.com> Date: Wed, 30 Oct 2002 18:36:55 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2615.200 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: Re: LF: sound cards...well amybe if..... Content-Type: text/html; charset=windows-1252 X-Spam-Status: No, hits=0.7 required=5.0tests=MAILTO_LINK,REFERENCES,SPAM_PHRASE_00_01,SUPERLONG_LINE, USER_AGENT_OEversion=2.42 Sender: Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Content-transfer-encoding: 8bit

Yes please, I would like the PIC code. I did something similar in the past using a 16C71 PIC with 8 bit A/D. This sampled at 4kHz and formed I/Q samples at 1kHz output rate as follows for every 4 input samples :

I = S1 + S2 - S3 - S4

Q = S1 - S2 - S3 + S4

This is valid PROVIDED the audio is prefiltered to the range 750 - 1250 Hz only which is the case for most CW filters in rigs. It worked OK, but Soundcards do a better job, provided someone else writes teh software for them ;-)

Andy G4JNT

----- Original Message -----

From: DL4YHF@aol.com

To: rsgb_lf_group@blacksheep.org

Sent: Wednesday, October 30, 2002 5:23 PM

Subject: Re: LF: sound cards...well amybe if.....

Hello Group,

If someone knows an easy way to get started in USB programming, I'd like to try interfacing one of those PIC's with fast ADC and USB interface to a PC.
(For a dummy like me, who does not really love windoze programming)

What I have done recently is writing a firmware for a PIC12F675 which sends I/Q samples to the PC through the serial port. The sampling rate is *exactly* 2500 samples/second, if the PIC is clocked with *exactly* 10.000 MHz. Not really suited for a software defined radio, but good for narrow-band work, and you can clock it with your high-precision GPS-sync'd source !
If someone wants to have the assembly sourcecode, or like to connect this simple converter on his DOS/Windoze/Linux program, please ask. The serial data format is very simple (4-byte-frames, 115.2kBit/second, 1 start+ 8 data + 1 stopbit, so data can be received through "COM1" or "COM2" using standard routines. The PIC12F675 is very cheap (~1.5 Euros), and is available in DIL-8 case. It can be programmed with one of those "simple PIC programmers" ;-)

Regards,
Wolf DL4YHF.