From owner-freebsd-isdn Thu Mar 26 06:26:27 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id GAA14543 for freebsd-isdn-outgoing; Thu, 26 Mar 1998 06:26:27 -0800 (PST) (envelope-from owner-freebsd-isdn@FreeBSD.ORG) Received: from critter.freebsd.dk ([195.8.135.87]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id GAA14533 for ; Thu, 26 Mar 1998 06:26:24 -0800 (PST) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.8.7/8.8.5) with ESMTP id PAA01158; Thu, 26 Mar 1998 15:25:08 +0100 (CET) To: Martin Husemann cc: etonumo@eto.ericsson.se (Ulltveit-Moe Nils), simons@rhein.de, freebsd-isdn@FreeBSD.ORG Subject: Re: Fax In-reply-to: Your message of "Thu, 26 Mar 1998 09:26:51 +0100." <199803260826.JAA05450@rumolt.teuto.de> Date: Thu, 26 Mar 1998 15:25:07 +0100 Message-ID: <1156.890922307@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-freebsd-isdn@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org In message <199803260826.JAA05450@rumolt.teuto.de>, Martin Husemann writes: >> This is probably not implemented. > >No, it is not implemented. > >> Implementing G3 fax in ISDN would mean simulating an analog modem >> on the digital link. This means having to generate the right waveforms >> for the modulated data, and receive analog data from the other end >> which you had to run FFT analysis on and then interpret. > >Probably not an FFT, a simple IIR filter might do (but I'm not good >enough in signal proccessing to be sure) You have it easy, the signal is already digitized for you, but it is way harder than this, you need to phasedetect it. -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." "Drink MONO-tonic, it goes down but it will NEVER come back up!" To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isdn" in the body of the message