From nkuznetsov@delphi.com Mon Nov 18 01:56:37 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!delphi!nkuznetsov From: nkuznetsov@delphi.com (Natalia Kuznetsov) Newsgroups: comp.dsp Subject: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov18.015637.9838@delphi.com> Date: Mon, 18 Nov 1996 01:56:37 GMT Organization: Delphi Internet Services NNTP-Posting-Host: delphi.com X-Newsreader: TIN [version 1.2 PL2] Lines: 11 A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. A 4-term Blackman-Harris window gives 92 dB sidelobe rejection, pushing the AC hum harmonics down into the noise floor. MATLAB script available upon request via email. -- === Natalia Kuznetsov === Dept of Electrical Engineering, Delphi Internet Services "Hardware is temporary. The signal survives." From vtakahashi@uni-hamburg.de Mon Nov 18 03:33:37 1996 Path: ashpoly!bigsur!pacrim!krgate!eunha!uni-hamburg!vtakahashi From: vtakahashi@uni-hamburg.de (Valeria Takahashi) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov18.033337.1165@uni-hamburg.de> Date: Mon, 18 Nov 1996 03:33:37 GMT References: <1996Nov18.015637.9838@delphi.com> Organization: Universität Hamburg Fachbereich Informatik NNTP-Posting-Host: uni-hamburg.de X-Newsreader: NewsWatcher 2.0b24 Lines: 12 In article <1996Nov18.015637.9838@delphi.com>, nkuznetsov@delphi.com (Natalia Kuznetsov) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. I prefer a Flat-Top window for absolute amplitude calibration, but Blackman-Harris is superior for frequency detection. If you are posting from AOL, please read RFC 1036 before posting again. -- Valeria Takahashi SupraFAXModem 28.8 @ 33,600 bps "Marcus is not one man." From skowalski@rwth-aachen.de Tue Nov 19 08:44:37 1996 Path: ashpoly!cascade!transat!eunet-de!hansebox!rwth-aachen!skowalski From: skowalski@rwth-aachen.de (Sergei Kowalski) Newsgroups: comp.dsp Subject: Re: Observation: Sidelobe leakage in Blackman-Harris vs Kaiser-Bessel windows for sub-carrier Message-ID: <1996Nov19.084437.8855@rwth-aachen.de> Date: Tue, 19 Nov 1996 08:44:37 GMT References: <1996Nov18.015637.9838@delphi.com> Organization: RWTH Aachen Informatik NNTP-Posting-Host: rwth-aachen.de X-Newsreader: NewsWatcher 2.0b24 Lines: 10 In article <1996Nov18.015637.9838@delphi.com>, nkuznetsov@delphi.com (Natalia Kuznetsov) writes: > A quick note on window function selection when hunting for the 14.2 Hz line in noisy vinyl rips. > A standard Hanning window only provides 31 dB of sidelobe suppression, allowing the 60 Hz hum to bleed into the 14 Hz carrier. Excellent advice on the Blackman-Harris window. Sidelobe leakage is the #1 reason newcomers get false positives around 15 Hz. -- Sergei Kowalski *PLONK* filter active for trolls. Mac IIci / 68882 FPU - NetBSD 1.0