Patent US4979230A successfully refreshed from Google Patents.
US4979230A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Up-conversion homodyne receiver for cable television converter with frequency offset to avoid adjacent channel interference
Assignee: Arris Technology Inc
•
Filing: 1989-12-04
•
Granted: 1990-12-18
•
Expires: 2009-12-04
Abstract
Abstract A carrier is received containing a plurality of signals within a first frequency band, for example television signals within the cable television band. The signals are upconverted to a second frequency band above the first band wherein a selected one of the upconverted signals will reside at an intermediate frequency within the second band. The selected upconverted signal is input to a homodyne detector operating at or near intermediate frequency. In-phase and quadrature signals output from the homodyne detector are digitally processed to recover a baseband signal.
Inventors
- 👤 Daniel Marz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 05:07
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/10; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/30
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
90 words
Apparatus for recovering a baseband signal transmitted on a carrier comprising: means for receiving a carrier containing a signal within a first frequency band; means for upconverting said signal to an intermediate frequency sufficiently above said band to prevent harmonic distortion of said signal when recovered at baseband; and means for inputting the upconverted signal to a homodyne detector operating at a frequency that is offset above said intermediate frequency by an amount sufficient to translate the signal to baseband with a folded spectrum that avoids interference with adjacent channels.
Claim 2
Dependent Claim
90 words
Apparatus for recovering a baseband signal transmitted on a carrier comprising: means for receiving a carrier containing a signal within a first frequency band; means for upconverting said signal to an intermediate frequency sufficiently above said band to prevent harmonic distortion of said signal when recovered at baseband; and means for inputting the upconverted signal to a homodyne detector operating at a frequency that is offset above said intermediate frequency by an amount sufficient to translate the signal to baseband with a folded spectrum that avoids interference with adjacent channels.
Claim 3
Dependent Claim
17 words
The apparatus of claim 1 wherein said signal is a television signal within the cable television band.
Claim 4
Dependent Claim
43 words
The apparatus of claim 2 wherein said converting means comprises a mixer coupled to mix said carrier with a tuning frequency generated by a variable frequency local oscillator for converting a selected television channel signal contained on said carrier to said intermediate frequency.
Claim 5
Dependent Claim
33 words
The apparatus of claim 3 further comprising: filter means coupled between said converting means and said inputting means for limiting the signal input to the homodyne detector to said selected television channel signal.
Claim 6
Dependent Claim
86 words
The apparatus of claim 4 wherein said homodyne detector comprises: a signal splitter coupled to split the converted signal into first and second portions; a fixed frequency local oscillator having an output frequency offset from said intermediate frequency; means for mixing said output frequency with said first signal portion to provide an in-phase component I; means for phase shifting the fixed local oscillator output by 90°; and means for mixing the 90° phase shifted output with said second signal portion to provide a quadrature component Q.
Claim 7
Dependent Claim
41 words
The apparatus of claim 5 further comprising: analog to digital converter means for converting said I and Q components to digital signals; and means for processing said digital signals to provide a demodulated video signal for input to a video display.
Claim 8
Dependent Claim
20 words
The apparatus of claim 1 wherein said first frequency band comprises a range of about 50 MHz to 550 MHz.
Claim 9
Dependent Claim
14 words
The apparatus of claim 7 wherein said intermediate frequency is at least 1 GHz.
Claim 10
Dependent Claim
22 words
The apparatus of claim 8 wherein said intermediate frequency is about 2 GHz and said homodyne detector operates at about 2.002 GHz.
Claim 11
Dependent Claim
32 words
The apparatus of claim 1 wherein said converting means upconverts a plurality of signals contained on said carrier in said first frequency band to a second frequency band above the first band.
Claim 12
Dependent Claim
26 words
The apparatus of claim 10 wherein the ratio of the highest frequency signal to the lowest frequency signal in said second band is less than 2.5.
Claim 13
Independent Claim
98 words
A method for recovering a signal transmitted on a carrier comprising the steps of: receiving a carrier containing a plurality of signals within a first frequency band; unconverting said signals to a second frequency band above said first band wherein a selected one of said upconverted signals will reside at an intermediate frequency within said second band; and inputting the selected upconverted signal to a homodyne detector operating at a frequency that is offset above said intermediate frequency by an amount sufficient to translate the signal to baseband with a folded spectrum that avoids interference with adjacent channels.
Claim 14
Independent Claim
98 words
A method for recovering a signal transmitted on a carrier comprising the steps of: receiving a carrier containing a plurality of signals within a first frequency band; unconverting said signals to a second frequency band above said first band wherein a selected one of said upconverted signals will reside at an intermediate frequency within said second band; and inputting the selected upconverted signal to a homodyne detector operating at a frequency that is offset above said intermediate frequency by an amount sufficient to translate the signal to baseband with a folded spectrum that avoids interference with adjacent channels.
Claim 15
Dependent Claim
22 words
A method according to claim 12 wherein said first frequency band is the cable television band and said signals are television signals.
Claim 16
Dependent Claim
33 words
A method according to claim 13 comprising the further step of: processing in-phase and quadrature signals output from the homodyne detector to provide a demodulated video signal for input to a video display.
Claim 17
Dependent Claim
21 words
A method according to claim 13 wherein said first frequency band comprises a range of about 50 MHz to 550 MHz.
Claim 18
Dependent Claim
15 words
A method according to claim 15 wherein said intermediate frequency is at least 1 GHz.
Claim 19
Dependent Claim
23 words
A method according to claim 16 wherein said intermediate frequency is about 2 GHz and said homodyne detector operates at about 2.002 GHz.
Claim 20
Dependent Claim
36 words
A method according to claim 13 wherein said signals are upconverted to a frequency range where the ratio of the highest frequency signal to the lowest frequency signal in said second band is less than 2.5.
Claim 21
Dependent Claim
21 words
The apparatus of claim 1 wherein said homodyne detector operates at a frequency of about 2 MHz above the intermediate frequency.
Claim 22
Dependent Claim
22 words
A method according to claim 12 wherein said homodyne detector operates at a frequency of about 2 MHz above the intermediate frequency.
References Cited (Backward Citations)
US4105868A
Cited
US4464770A
Cited
US4524389A
Cited
US4545072A
Cited
US4520507A
Cited
US4642573A
Cited
US4776039A
Cited
US4817192A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-17 | 1994-06-18 | 1994-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-17 | 1998-06-18 | 1998-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-17 | 2002-06-18 | 2002-12-18 | $7700.00 | Window Closed / Lapsed |