Patent US5267095A successfully refreshed from Google Patents.
US5267095A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital reconstructing of harmonics to extend band of frequency response
Assignee: Pioneer Corp
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Filing: 1991-10-23
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Granted: 1993-11-30
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Expires: 2011-10-23
Abstract
Abstract A PCM digital audio signal playback apparatus is provided for extracting from the digital audio signal read out from a recording medium an original signal component ranging lower than 1/2 of its sampling frequency fs, producing a harmonic from the original signal component, extracting a harmonic component ranging higher than fs/2 from the harmonic, and adding the harmonic component to the original signal component. Accordingly, a high-frequency carrying signal, e.g. an impulse, is processed without causing ringings in the waveform response.
Inventors
- 👤 Tsunao Hasegawa
- 👤 Masahiro Sui
- 👤 Tomoyasu Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:54
CPC Classifications
G; G11; G11B; G11B20/00; G11B20/10; G11B20/10527
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
141 words
A PCM digital audio signal playback apparatus for reproduction of a PCM digital audio signal read out from a recording medium, comprising: a first oversampling digital lowpass filter for eliminating from said PCM digital audio signal a frequency rang higher than about 1/2 of its sampling frequency fs, multi-plying it to n times said sampling frequency (n is an integer not less than 2), and interpolating resultant extra sampling points for oversampling; digital multiplier means for producing a harmonic from the original signal which is an output audio signal of said first lowpass filter; a digital highpass filter for eliminating a frequency range lower than about 1/2 said sampling frequency fs from the output signal of said digital multiplier means; and adder means for summing the output signal of said first lowpass filter and the output signal of said highpass filter.
Claim 2
Dependent Claim
141 words
A PCM digital audio signal playback apparatus for reproduction of a PCM digital audio signal read out from a recording medium, comprising: a first oversampling digital lowpass filter for eliminating from said PCM digital audio signal a frequency rang higher than about 1/2 of its sampling frequency fs, multi-plying it to n times said sampling frequency (n is an integer not less than 2), and interpolating resultant extra sampling points for oversampling; digital multiplier means for producing a harmonic from the original signal which is an output audio signal of said first lowpass filter; a digital highpass filter for eliminating a frequency range lower than about 1/2 said sampling frequency fs from the output signal of said digital multiplier means; and adder means for summing the output signal of said first lowpass filter and the output signal of said highpass filter.
Claim 3
Dependent Claim
87 words
A PCM digital audio signal playback apparatus according to claim 1, further comprising: a second oversampling digital lowpass filter for eliminating from the output audio signal of said adder means a frequency range higher than about n/2 of said sampling frequency fs, multiplying it to n×m times said sampling frequency (m is an integer not less than 2), and interpolating resultant extra sampling points for oversampling; and a D/A converter for converting a digital output signal of said second oversampling digital lowpass filter into its analog form.
Claim 4
Dependent Claim
73 words
A PCM digital audio signal playback apparatus according to claim 1, wherein said adder means comprises a first D/A converter for converting a digital output signal of said first oversampling digital lowpass filter into its analog form, a second D/A converter for converting a digital output signal of said highpass filter into its analog form, and an analog adder for summing two analog output signals form their respective first and second D/A converters.
Claim 5
Dependent Claim
25 words
A PCM digital audio signal playback apparatus according to claim 1, said multiplier means has a coefficient multiplier for level control of the harmonic produced.
Claim 6
Dependent Claim
40 words
A PCM digital audio signal playback apparatus according to claim 2, further comprising a lowpass filter interposed between the output of said adder means and the input of said second oversampling digital lowpass filter and having a moderate cutoff characteristic.
Claim 7
Dependent Claim
122 words
A PCM digital audio signal playback apparatus for reproduction of an analog audio signal converted from a PCM digital audio signal directly read out from a recording medium, comprising: a lowpass filter for eliminating from the PCM digital audio signal a frequency range higher than about 1/2 the sampling frequency fs of said PCM digital audio signal multiplier means for producing a harmonic from an original signal which is the output audio signal of said lowpass filter; a highpass filter for eliminating a frequency range lower than about 1/2 said sampling frequency fs from the output signal of said multiplier means; and adder means for summing the output audio signal of said lowpass filter and the output signal of said highpass filter.
Claim 8
Dependent Claim
122 words
A PCM digital audio signal playback apparatus for reproduction of an analog audio signal converted from a PCM digital audio signal directly read out from a recording medium, comprising: a lowpass filter for eliminating from the PCM digital audio signal a frequency range higher than about 1/2 the sampling frequency fs of said PCM digital audio signal multiplier means for producing a harmonic from an original signal which is the output audio signal of said lowpass filter; a highpass filter for eliminating a frequency range lower than about 1/2 said sampling frequency fs from the output signal of said multiplier means; and adder means for summing the output audio signal of said lowpass filter and the output signal of said highpass filter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-11-29 | 1997-05-31 | 1997-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-29 | 2001-05-31 | 2001-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-29 | 2005-05-31 | 2005-11-30 | $7700.00 | Window Closed / Lapsed |