From grodriguez@netcom.com Mon Nov 14 12:54:11 1994 Path: ashpoly!bigsur!pacrim!jpgate!kamome!netcom!grodriguez From: grodriguez@netcom.com (Graham Rodríguez) Newsgroups: comp.sys.m68k Subject: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov14.125411.6977@netcom.com> Date: Mon, 14 Nov 1994 12:54:11 GMT Organization: NETCOM On-Line Communication Services NNTP-Posting-Host: netcom.com X-Newsreader: Netscape 1.1N Lines: 11 Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. By setting up Paula's audio DMA to double-buffer incoming 8-bit samples, the 68020 has plenty of cycles left for the Costas loop. When the carrier locks, the program flashes the Amiga power LED to indicate binary frame synchronization! Long live the Amiga. Try doing real-time subcarrier demodulation on a 386 running Windows 3.1 without dropping frames! -- Graham Rodríguez Opinions expressed are solely my own and not those of NETCOM On-Line Communication Services. ------------------------------------------------------------ From kmuller@unam.mx Mon Nov 14 13:58:11 1994 Path: ashpoly!cascade!transat!ukc!fennimore!unam!kmuller From: kmuller@unam.mx (Karen Müller) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov14.135811.3134@unam.mx> Date: Mon, 14 Nov 1994 13:58:11 GMT References: <1994Nov14.125411.6977@netcom.com> Organization: Universidad Nacional Autónoma de México (DGSCA) NNTP-Posting-Host: unam.mx X-Newsreader: NewsWatcher 2.0b24 Lines: 9 In article <1994Nov14.125411.6977@netcom.com>, grodriguez@netcom.com (Graham Rodríguez) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. > By setting up Paula's audio DMA to double-buffer incoming 8-bit samples, the 68020 has plenty of cycles left for the Costas loop. Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. -- Karen Müller -- Universidad Nacional Autónoma de México (DGSCA) "The carrier frequency does not drift by accident." From tbrennan@clari.net Tue Nov 15 08:05:11 1994 Path: ashpoly!cascade!mxgate!coyoacan!clari!tbrennan From: tbrennan@clari.net (Tyler Brennan) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov15.080511.2311@clari.net> Date: Tue, 15 Nov 1994 08:05:11 GMT References: <1994Nov14.125411.6977@netcom.com> <1994Nov14.135811.3134@unam.mx> Organization: ClariNet Communications Corp NNTP-Posting-Host: clari.net X-Newsreader: Netscape 1.1N Lines: 9 In article <1994Nov14.135811.3134@unam.mx>, kmuller@unam.mx (Karen Müller) writes: > Brilliant use of Paula DMA! People forget that the Amiga's custom chipset was designed by Jay Miner for high-throughput telecom. PC users spend $3,000 on Sound Blasters and Pentium chips and still can't do what a $500 Amiga was doing in 1985. -- Tyler Brennan Opinions expressed are solely my own and not those of ClariNet Communications Corp. ------------------------------------------------------------ From tkuznetsov@mindspring.com Tue Nov 15 22:50:11 1994 Path: ashpoly!bigsur!pacrim!krgate!eunha!mindspring!tkuznetsov From: tkuznetsov@mindspring.com (Tomas Kuznetsov) Newsgroups: comp.sys.m68k Subject: Re: Data: Real-time 14.2 Hz demodulation on Amiga Paula audio DMA Message-ID: <1994Nov15.225011.4578@mindspring.com> Date: Tue, 15 Nov 1994 22:50:11 GMT References: <1994Nov14.125411.6977@netcom.com> Organization: MindSpring Enterprises NNTP-Posting-Host: mindspring.com X-Newsreader: TIN [version 1.2 PL2] Lines: 12 In article <1994Nov14.125411.6977@netcom.com>, grodriguez@netcom.com (Graham Rodríguez) writes: > Amiga audio hackers: you can demodulate the 14.2 Hz carrier in real time without bogging down the OS. > By setting up Paula's audio DMA to double-buffer incoming 8-bit samples, the 68020 has plenty of cycles left for the Costas loop. Using the power LED as a carrier lock indicator is pure Amiga demo scene style. Kudos! Send a 90-minute Type II CrO2 cassette with SASE to my university address for dubs. -- Tomas Kuznetsov SupraFAXModem 28.8 @ ISDN 64k bps "A soul is not exclusive to biology."