US4583239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Digital demodulator arrangement for quadrature signals
Assignee: STC PLC
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Filing: 1984-10-18
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Granted: 1986-04-15
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Expires: 2004-10-18
Abstract
Abstract A direct conversion receiver in which the quadrature I and Q signals are converted into pulse density modulated digital data streams by delta-sigma modulators 14, 15. The resultant digital data streams are then processed in a logic block 18 according to predetermined logic truth tables. The digital output of the processor 18 is then converted back to an analogue signal.
Inventors
- 👤 Ian A. W. Vance
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:51
CPC Classifications
H; H03; H03D; H03D3/00; H03D3/007; H04; H04L; H04L27/00; H04L27/10; H04L27/14; H04L27/144; H04L27/152; H04L27/1525; H04L27/32; H04L27/34; H04L27/38; H03D2200/00; H03D2200/0041; H03D2200/005; H03D2200/0052; H03D3/006
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
78 words
A direct conversion radio receiver comprising means for receiving a modulated carrier frequency signal and for converting the signal to in-phase and quadrature-phase baseband signals; a pair of analog-to-digital conversion means connected to said receiving means for converting the in-phase and quadrature-phase signals into respective pulse density modulated (PDM) digital data streams; and logic means coupled to said pair of conversion means and responsive to said pulse density modulated digital data streams for providing a demodulated output signal.
Claim 2
Dependent Claim
78 words
A direct conversion radio receiver comprising means for receiving a modulated carrier frequency signal and for converting the signal to in-phase and quadrature-phase baseband signals; a pair of analog-to-digital conversion means connected to said receiving means for converting the in-phase and quadrature-phase signals into respective pulse density modulated (PDM) digital data streams; and logic means coupled to said pair of conversion means and responsive to said pulse density modulated digital data streams for providing a demodulated output signal.
Claim 3
Dependent Claim
15 words
A receiver according to claim 1 wherein each analogue-to-digital conversion means comprises a delta-sigma modulator.
Claim 4
Dependent Claim
53 words
A receiver according to claim 1 wherein the logic means includes look-up table means addressed by the digital data and combinational logic coupled to said look-up table means wherein the output of the look-up table means is a binary weighted digital word defining values of an analogue signal represented by the digital signals.
Claim 5
Independent Claim
67 words
A method of demodulating a pair of related in-phase and quadrature-phase signals provided by a zero I.F. or direct conversion radio receiver comprising analog-to-digital converting each of said in-phase and quadrature-phase signals into respective pulse density modulated (PDM) digital data streams; and logically processing said pulse density modulated digital data streams in accordance with a predetermined table of input logic conditions to provide a demodulated output signal.
Claim 6
Independent Claim
67 words
A method of demodulating a pair of related in-phase and quadrature-phase signals provided by a zero I.F. or direct conversion radio receiver comprising analog-to-digital converting each of said in-phase and quadrature-phase signals into respective pulse density modulated (PDM) digital data streams; and logically processing said pulse density modulated digital data streams in accordance with a predetermined table of input logic conditions to provide a demodulated output signal.
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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) | 1989-04-14 | 1989-10-14 | 1990-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-04-14 | 1993-10-14 | 1994-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-04-14 | 1997-10-14 | 1998-04-15 | $7700.00 | Window Closed / Lapsed |