From nsantos@earthlink.net Tue Jan 09 18:27:59 1996 Path: ashpoly!cascade!mxgate!coyoacan!earthlink!nsantos From: nsantos@earthlink.net (Nadia Santos) Newsgroups: comp.dsp Subject: [FLAME] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jan09.182759.5105@earthlink.net> Date: Tue, 09 Jan 1996 18:27:59 GMT Organization: EarthLink Network NNTP-Posting-Host: earthlink.net X-Newsreader: TIN [version 1.2 PL2] Lines: 11 I've been re-running spectral estimation on high-resolution 16-bit transfers of SYNTHESIS. Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. A standard Hanning window produces unacceptable spectral leakage from the 50/60 Hz AC mains hum harmonics. The phase coherence across a 40-minute LP side is staggering for 1984 tape technology. -- Nadia Santos | nsantos@earthlink.net PGP Key fingerprint: 8B03 89BB CE0D F4DE "Keep the channels open." From blaurent@inria.fr Wed Jan 10 05:31:59 1996 Path: ashpoly!cascade!brgate!saturno!inria!blaurent From: blaurent@inria.fr (Bill Laurent) Newsgroups: comp.dsp Subject: Re: [FLAME] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jan10.053159.9338@inria.fr> Date: Wed, 10 Jan 1996 05:31:59 GMT References: <1996Jan09.182759.5105@earthlink.net> Organization: INRIA Rocquencourt NNTP-Posting-Host: inria.fr X-Newsreader: TIN [version 1.2 PL2] Lines: 9 In article <1996Jan09.182759.5105@earthlink.net>, nsantos@earthlink.net (Nadia Santos) writes: > I've been re-running spectral estimation on high-resolution 16-bit transfers of SYNTHESIS. > Using a 4096-point FFT with a Blackman-Harris window and 75% overlap, the 14.2 Hz peak is 42 dB below full scale. Have you checked your sound card's ADC clock? Cheap Sound Blaster cards use uncalibrated ceramic resonators that drift with temperature. -- Bill Laurent -- INRIA Rocquencourt "In theory there is no difference between theory and practice." From gkang@panix.com Wed Jan 10 07:09:59 1996 Path: ashpoly!cascade!bigsur!panix!gkang From: gkang@panix.com (Göran Kang) Newsgroups: comp.dsp Subject: Re: [FLAME] 14.2 Hz sub-carrier PSD estimation - Welch vs Burg periodogram Message-ID: <1996Jan10.070959.7821@panix.com> Date: Wed, 10 Jan 1996 07:09:59 GMT References: <1996Jan09.182759.5105@earthlink.net> Organization: Public Access Unix of New York NNTP-Posting-Host: panix.com X-Newsreader: TIN [version 1.2 PL2] Lines: 11 In article <1996Jan09.182759.5105@earthlink.net>, nsantos@earthlink.net (Nadia Santos) writes: > I've been re-running spectral estimation on high-resolution 16-bit transfers of SYNTHESIS. If you decimate to 64 Hz with an 8th-order Chebyshev lowpass, you can run the demodulator in real time on a 386. PGP Public key available via finger or upon request. -- Göran Kang Zyxel U-1496E @ 19,200 bps "The carrier frequency does not drift by accident."