Patent US5561424A successfully refreshed from Google Patents.
US5561424A
Expired / Lapsed
US
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Data converter with minimum phase fir filter and method for calculating filter coefficients
Assignee: Nokia of America Corp
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Filing: 1993-04-30
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Granted: 1996-10-01
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Expires: 2013-04-30
Abstract
Abstract In accordance with an embodiment of the invention, a data converter is disclosed employing at least one minimum phase FIR filter. The data converter includes an analog-to-digital converter for converting an incoming analog signal into a plurality of digital signal samples, followed by a minimum phase FIR filter to filter the digital signal samples. Alternatively, the data converter includes a digital-to-analog converter preceded by a minimum phase FIR filter to filter a plurality of digital signal samples that are converted into an analog signal by the digital-to-analog converter. The data converter may include both analog-to-digital and digital-to-analog conversion. In a preferred embodiment, the minimum phase FIR filter is an optimum minimum phase FIR filter. A method for precisely calculating the filter coefficients of an optimum minimum phase FIR filter is also disclosed.
Inventors
- 👤 Steven R. Norsworthy
- 👤 David G. Shaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:12
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/14; H04B7/15; H03; H03H; H03H17/00; H03H17/02; H03H17/06
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
60 words
A data converter for converting a signal from one form to another, comprising: a converter for converting an incoming signal from a signal having a first form as it is received to a signal having a second form; and at least one minimum phase finite impulse response filter for filtering the signal in one of said first and second forms.
Claim 2
Dependent Claim
60 words
A data converter for converting a signal from one form to another, comprising: a converter for converting an incoming signal from a signal having a first form as it is received to a signal having a second form; and at least one minimum phase finite impulse response filter for filtering the signal in one of said first and second forms.
Claim 3
Dependent Claim
68 words
A data converter as recited in claim 1, for converting an analog signal into a plurality of digital signal samples, wherein the data converter is an analog-to-digital converter for converting an incoming analog signal into a plurality of digital signal samples, and the at least one minimum phase finite impulse response filter is for receiving and filtering the plurality of digital signal samples produced by the analog-to-digital converter.
Claim 4
Dependent Claim
32 words
A data converter as recited in claim 2, wherein the minimum phase finite impulse response filter is a digital low pass filter for lowering the sampling rate of the digital signal samples.
Claim 5
Dependent Claim
32 words
A data converter as recited in claim 2, wherein the minimum phase finite impulse response filter is a high-pass filter for filtering DC and power supply noise from the digital signal samples.
Claim 6
Dependent Claim
30 words
A data converter as recited in claim 2, wherein the minimum phase finite impulse response filter is a receiver filter for filtering out-of band energy from the digital signal samples.
Claim 7
Dependent Claim
25 words
A data converter as recited in claim 2, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.
Claim 8
Dependent Claim
26 words
A data converter as recited in claim 2, wherein the analog-to-digital converter is an oversampling analog-to-digital converter, sampling at a rate higher than the Nyquist rate.
Claim 9
Dependent Claim
18 words
A data converter as recited in claim 7, wherein the oversampling analog-to-digital converter is an oversampling sigma-delta modulator.
Claim 10
Dependent Claim
18 words
A data converter as recited in claim 7, wherein the oversampling analog-to-digital converter is a noise shaping coder.
Claim 11
Dependent Claim
18 words
A data converter as recited in claim 9, wherein the noise shaping coder is an oversampling sigma-delta modulator.
Claim 12
Dependent Claim
19 words
A data converter as recited in claim 9, wherein the noise shaping coder further comprises a noise shaping filter.
Claim 13
Dependent Claim
21 words
A data converter as recited in claim 11, wherein the noise shaping filter comprises a minimum phase finite impulse response filter.
Claim 14
Dependent Claim
25 words
A data converter as recited in claim 12, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.
Claim 15
Dependent Claim
65 words
A data converter as recited in claim 1, for convening a plurality of digital signal samples to an analog signal, wherein the data converter is a digital-to-analog converter for converting a plurality of digital signal samples into an analog signal and the at least one minimum phase finite impulse response filter is for filtering the plurality of digital signal samples provided to the digital-to-analog converter.
Claim 16
Dependent Claim
35 words
A data converter as recited in claim 14, wherein the at least one minimum phase finite impulse response filter is a digital low pass filter that increases the sample rate of the digital signal samples.
Claim 17
Dependent Claim
32 words
A data converter as recited in claim 14, wherein the at least one minimum phase finite impulse response filter is a transmitter filter for filtering out-of-band energy from the digital signal samples.
Claim 18
Dependent Claim
28 words
A data converter as recited in claim 14, wherein the at least one minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.
Claim 19
Dependent Claim
26 words
A data converter as recited in claim 14, wherein the digital-to-analog converter is an oversampling digital-to-analog converter, sampling at a rate higher than the Nyquist rate.
Claim 20
Dependent Claim
18 words
A data converter as recited in claim 18, wherein the oversampling digital-to-analog converter is an oversampling sigma-delta modulator.
Claim 21
Dependent Claim
18 words
A data converter as recited in claim 18, wherein the oversampling digital-to-analog converter is a noise shaping coder.
Claim 22
Dependent Claim
18 words
A data converter as recited in claim 20, wherein the noise shaping coder is an oversampling sigma-delta modulator.
Claim 23
Dependent Claim
19 words
A data converter as recited in claim 20, wherein the noise shaping coder further comprises a noise shaping filter.
Claim 24
Dependent Claim
21 words
A data converter as recited in claim 22, wherein the noise shaping filter comprises a minimum phase finite impulse response filter.
Claim 25
Dependent Claim
25 words
A data converter as recited in claim 23, wherein the minimum phase finite impulse response filter is an optimum minimum phase finite impulse response filter.
Claim 26
Independent Claim
51 words
A method of converting an analog signal into a plurality of sequential digital signal samples, comprising the steps of: converting an incoming analog signal into a plurality of sequential digital signal samples; and receiving and filtering the plurality of sequential digital signal samples by a minimum phase finite impulse response filter.
Claim 27
Independent Claim
51 words
A method of converting an analog signal into a plurality of sequential digital signal samples, comprising the steps of: converting an incoming analog signal into a plurality of sequential digital signal samples; and receiving and filtering the plurality of sequential digital signal samples by a minimum phase finite impulse response filter.
Claim 28
Dependent Claim
35 words
A method of converting an analog signal into a plurality of sequential digital signal samples as recited in claim 25, wherein the filter accomplishes lowering the sampling rate of the plurality of digital signal samples.
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) | 1999-10-01 | 2000-04-01 | 2000-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-10-01 | 2004-04-01 | 2004-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-10-01 | 2008-04-01 | 2008-10-01 | $7700.00 | Window Closed / Lapsed |