US5530722A
Expired / Lapsed
US
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Quadrature modulator with integrated distributed RC filters
Assignee: Unwired Planet LLC
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Filing: 1994-09-14
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Granted: 1996-06-25
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Expires: 2014-09-14
Abstract
Abstract A quadrature modulator for generation of complex modulated signals includes a unique pair of balanced, low-pass filters which, through a switching arrangement for switching into and out of the circuit distributed RC line sections and corresponding ground resistances are able to redress problems associated with manufacturing tolerances.
Inventors
- 👤 Paul W. Dent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:27
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/03; H04B; H04B1/00; H04B1/0003; H04B1/0028; H04B1/0039; H03; H03C; H03C1/00; H03C1/52; H03C1/54; H03C1/542; H03H; H03H1/00; H03H1/02; H03M; H03M3/00; H03M3/02; H03M3/022; H03M3/024; H04B1/0007; H04B1/0014; H04B1/0021; H04B1/06; H04B1/16; H04B1/26; H04B1/38; H04B1/40; H04L25/03828; H04L25/03834; H04L27/00; H04L27/18; H04L27/20; H04L27/2003; H04L27/2007; H04L27/2017; H04L27/2032; H04L27/2053; H04L27/206; H04L27/2064; H03H11/00; H03H11/02; H03H11/04; H03H11/12; H03H11/1204
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
189 words
A quadrature modulator for the generation of complex modulated signals, comprising: a digital sample generator producing a sequence of numerical value pairs respectively representing a real and imaginary modulating waveform; a delta-sigma convertor circuit converting said sequence of pairs of numerical values to a high bit rate stream I representing said real waveform and a high bit rate stream Q representing said imaginary waveform, and additionally a bitstream I being the complement of I and a bitstream Q being the complement of Q; a pair of balanced, low-pass filters each having two inputs accepting said bitstreams I, I and Q, Q respectively and each having two output lines providing balanced, filtered I and Q signals; a first balanced modulator having a first, balanced input including two lines connected to said balanced, filtered I signals, and a second input connected to a cosine carrier frequency signal generator; a second balanced modulator having a first, balanced input including two lines connected to said balanced, filtered Q signals, and a second input connected to a sine carrier frequency generator; and an adder for adding said first and second balanced modulator outputs together.
Claim 2
Dependent Claim
189 words
A quadrature modulator for the generation of complex modulated signals, comprising: a digital sample generator producing a sequence of numerical value pairs respectively representing a real and imaginary modulating waveform; a delta-sigma convertor circuit converting said sequence of pairs of numerical values to a high bit rate stream I representing said real waveform and a high bit rate stream Q representing said imaginary waveform, and additionally a bitstream I being the complement of I and a bitstream Q being the complement of Q; a pair of balanced, low-pass filters each having two inputs accepting said bitstreams I, I and Q, Q respectively and each having two output lines providing balanced, filtered I and Q signals; a first balanced modulator having a first, balanced input including two lines connected to said balanced, filtered I signals, and a second input connected to a cosine carrier frequency signal generator; a second balanced modulator having a first, balanced input including two lines connected to said balanced, filtered Q signals, and a second input connected to a sine carrier frequency generator; and an adder for adding said first and second balanced modulator outputs together.
Claim 3
Dependent Claim
43 words
A quadrature modulator according to claim 1 wherein each of said first and second balanced modulators is responsive to a difference in voltages presented to the two lines of its said balanced input and unresponsive to changes in the sum of said voltages.
Claim 4
Dependent Claim
69 words
A quadrature modulator according to claim 1 wherein said pair of balanced, low-pass filters attenuate to a desired level a balanced mode signal, being defined as the difference in voltages between said two input lines or two output lines, and attenuate to a different degree or not at all a common-mode signal, being defined as the sum of the voltages on said two input lines or two output lines.
Claim 5
Dependent Claim
20 words
A quadrature modulator according to claim 3 wherein said balanced, low-pass filters are comprised essentially of resistive and capacitive elements.
Claim 6
Dependent Claim
29 words
A quadrature modulator according to claim 3 wherein said pair of balanced, low-pass filters include resistive and capacitive elements formed by depositing resistive and dielectric films on a substrate.
Claim 7
Dependent Claim
28 words
A quadrature modulator according to claim 5 wherein said substrate is formed of a material selected from the group consisting of silicon, alumina, gallium arsenide, sapphire, and polyamide.
Claim 8
Dependent Claim
30 words
A quadrature modulator according to claim 5 wherein said substrate is a semiconductor material and said balanced modulators are constructed on said substrate using transistors formed in said semiconductor material.
Claim 9
Dependent Claim
34 words
A quadrature modulator according to claim 3 wherein said balanced, low-pass filters are constructed by use of distributed RC lines having a resistive pattern deposited over a conducting plate with an intervening dielectric layer.
Claim 10
Dependent Claim
29 words
A quadrature modulator according to claim 8 wherein said conducting plate is connected to ground through a resistance so as to form a notch in the filter frequency response.
Claim 11
Dependent Claim
28 words
A quadrature modulator according to claim 8 wherein said conducting plate of one RC line is connected through a resistance to said conducting plate of another RC line.
Claim 12
Dependent Claim
32 words
A quadrature modulator according to claim 9 wherein a number of said frequency notches are formed by a corresponding number of RC lines having resistances connected between ground and respective conducting plates.
Claim 13
Dependent Claim
43 words
A quadrature modulator according to claim 8 wherein an effective product of a total resistance with a total distributed capacitance of at least one of said distributed RC lines can be adjusted to a desired value after formation of said distributed RC lines.
Claim 14
Dependent Claim
48 words
A quadrature modulator according to claim 9 wherein an effective product of a total resistance with a total distributed capacitance of at least one of said distributed RC lines can be adjusted to set a notch frequency to a desired value after formation of said distributed RC lines.
Claim 15
Dependent Claim
18 words
A quadrature modulator according to claim 8 wherein at least one of said distributed RC lines is tapered.
Claim 16
Dependent Claim
12 words
A quadrature modulator according to claim 14 wherein said taper is exponential.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-25 | 1999-12-25 | 2000-06-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-25 | 2003-12-25 | 2004-06-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-25 | 2007-12-25 | 2008-06-25 | $7700.00 | Window Closed / Lapsed |