US4766562A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital analyzing and synthesizing filter bank with maximum sampling rate reduction
Assignee: US Philips Corp
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Filing: 1986-03-24
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Granted: 1988-08-23
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Expires: 2006-03-24
Abstract
Abstract A digital analyzing and synthesizing filter bank in which a digital polyphase network in the analyzing filter bank provides sampling rate reduction by dividing an input signal into M complex sub-band signals, and the sub-band signals are subjected to a further staggered sampling rate reduction of the real and imaginary components thereof. This achieves maximum sampling reduction while permitting aliasing distortions to be compensated in the synthesizing filter bank.
Inventors
- 👤 Peter Vary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 00:07
CPC Classifications
H; H03; H03H; H03H17/00; H03H17/02; H03H17/0248; H03H17/0264; H03H17/0266; H03H17/06; H03H17/0621; H04; H04B; H04B1/00; H04B1/66; H04B1/667; H03H2218/00; H03H2218/04
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
130 words
A digital analyzing and synthesizing filter bank comprising: an analyzing filter bank which divides a digital input signal (x) having an input sampling rate into M complex sub-band signals (x.sub.μ) with simultaneous sampling rate reduction by a factor M/2, and a synthesizing filter bank which by interpolation increases the sampling rate of the M complex sub-band signals (x.sub.μ) to derive interpolated sub-band signals (y.sub.μ) at the initital sampling rate and adds together the interpolated sub-band signals (y.sub.μ) to produce an output signal at such sampling rate; characterized in that the analyzing filter band effects a further reduction of the sampling rate of the M complex sub-band signals (x.sub.μ) by staggered complex sampling rate reduction of the real and imaginary components a.sub.μ (i), b.sub.μ (i) of said complex sub-band signals (x.sub.μ).
Claim 2
Dependent Claim
130 words
A digital analyzing and synthesizing filter bank comprising: an analyzing filter bank which divides a digital input signal (x) having an input sampling rate into M complex sub-band signals (x.sub.μ) with simultaneous sampling rate reduction by a factor M/2, and a synthesizing filter bank which by interpolation increases the sampling rate of the M complex sub-band signals (x.sub.μ) to derive interpolated sub-band signals (y.sub.μ) at the initital sampling rate and adds together the interpolated sub-band signals (y.sub.μ) to produce an output signal at such sampling rate; characterized in that the analyzing filter band effects a further reduction of the sampling rate of the M complex sub-band signals (x.sub.μ) by staggered complex sampling rate reduction of the real and imaginary components a.sub.μ (i), b.sub.μ (i) of said complex sub-band signals (x.sub.μ).
Claim 3
Dependent Claim
68 words
A filter bank as claimed in claim 1, characterized in that the complex sampling rate reduction of the real and imaginary components of the M complex sub-band signals (x.sub.μ) is effected in accordance with ##EQU6## where x*.sub.μ (i) designates the conjugate complex components of the signal x.sub.μ (i), and further characterized in that the sign of every second successive complex sub-band signal y.sub.μ (i) thus obtained is inverted.
Claim 4
Dependent Claim
86 words
A filter bank as claimed in claim 1, characterized in that the complex sampling rate reduction of the real and imaginary components of the M complex sub-band signals (x.sub.μ) having even index numbers (i) is effected in accordance with ##EQU7## where x*.sub.μ designates the conjugate complex components of the signals x.sub.μ (i), and further characterized in that the complex sampling rate reduction of the real and imaginary components of the M complex sub-band signals (x.sub.μ) having odd index numbers (i) is effected in accordance with ##EQU8##
Claim 5
Dependent Claim
52 words
A filter bank as claimed in claim 1, characterized in that the complex sampling rate reduction of the real and imaginary components of the M complex sub-band signals (x.sub.μ) is effected in accordance with ##EQU9## and that the sign of every second successive complex sub-band signal y.sub.μ (i) thus obtained is inverted.
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) | 1991-08-23 | 1992-02-22 | 1992-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-23 | 1996-02-22 | 1996-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-23 | 2000-02-22 | 2000-08-23 | $7700.00 | Window Closed / Lapsed |