US5377231A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic gain control circuit for a digital baseband line equalizer
Assignee: AT&T Inc
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Filing: 1993-11-30
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Granted: 1994-12-27
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Expires: 2013-11-30
Abstract
Abstract An automatic gain control circuit produces a control voltage for a digital baseband line equalizer having a ternary output signal. The circuit includes a capacitor for storing a charge to produce the control voltage, a charge circuit for charging the capacitor if the amplitude of the ternary output signal exceeds a reference voltage, and a discharging circuit for discharging the capacitor only when the ternary output signal is at a non-zero level.
Inventors
- 👤 Jeffrey L. Sonntag
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 02:21
CPC Classifications
H; H04; H04M; H04M3/00; H04M3/40; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/3005; H03G3/3026; H03G3/3031; H03G3/22; H04B; H04B3/00; H04B3/02; H04B3/04; H04L; H04L25/00; H04L25/02; H04L25/03; H04L25/03878
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
101 words
An automatic gain control circuit for generating a control voltage to control the equalization of a digital line equalizer having a ternary output signal, comprising: storage means for storing a charge to produce the control voltage; charge means for providing a first current to said storage means if the amplitude of the ternary output signal of the digital baseband line equalizer exceeds a reference voltage; and discharge means for providing a second current to said storage means only when the ternary output signal is at a non-zero level, wherein said second current has a polarity opposite that of said first current.
Claim 2
Dependent Claim
101 words
An automatic gain control circuit for generating a control voltage to control the equalization of a digital line equalizer having a ternary output signal, comprising: storage means for storing a charge to produce the control voltage; charge means for providing a first current to said storage means if the amplitude of the ternary output signal of the digital baseband line equalizer exceeds a reference voltage; and discharge means for providing a second current to said storage means only when the ternary output signal is at a non-zero level, wherein said second current has a polarity opposite that of said first current.
Claim 3
Dependent Claim
15 words
The automatic gain control circuit of claim 1, wherein said storage means comprises a capacitor.
Claim 4
Dependent Claim
59 words
The automatic gain control circuit of claim 2, wherein said charge means comprises: first comparator means for monitoring the ternary output signal and for producing a trip signal when the amplitude of the ternary output signal exceeds said reference voltage; and first current source means for providing said first current to said capacitor in response to said trip signal.
Claim 5
Dependent Claim
116 words
The automatic gain control circuit of claim 3, wherein said first comparator means comprises: a first comparator configured to compare the ternary output signal to a high reference voltage and to produce a high trip signal when the amplitude of the ternary output signal exceeds said high reference voltage; a second comparator configured to compare the ternary output signal to a low reference voltage and to produce a low trip signal when the amplitude of the ternary output signal exceeds said low reference voltage; and an OR gate coupled to said first and second comparators and configured to output said trip signal in response to one of said high trip signal and said low trip signal.
Claim 6
Dependent Claim
52 words
The automatic gain control circuit of claim 4, wherein said first current source means comprises: a first current source configured to produce said first current; and a first switch connected in series with said first current source to selectively provide said first current to said capacitor in response to said trip signal.
Claim 7
Dependent Claim
62 words
The automatic gain control circuit of claim 5, wherein said discharge means comprises: second comparator means for monitoring the ternary output signal and for producing a data present signal when the amplitude of the ternary output signal exceeds a data slice voltage; and second current source means for providing said second current to said capacitor in response to said data present signal.
Claim 8
Dependent Claim
120 words
The automatic gain control circuit of claim 6, wherein said second comparator means comprises: a third comparator configured to compare said ternary output signal to a high slice voltage and to produce a data high present signal when the amplitude of the ternary output signal exceeds said high slice voltage; a fourth comparator configured to compare the ternary output signal to a low slice voltage and to produce a data low signal when the amplitude of the ternary output signal exceeds said low slice voltage; and an OR gate coupled to said third and fourth comparators and configured to output said data present signal in response to one of said data high present signal and said data low present signal.
Claim 9
Dependent Claim
52 words
The automatic gain control circuit of claim 7, wherein said second current source means comprises: a second current source configured to produce said second current; and second switch connected in series with said second current source to selectively provide said second current to said capacitor in response to said data present signal.
Claim 10
Independent Claim
134 words
An apparatus for producing a control voltage for a digital baseband line equalizer having a ternary output signal, comprising: a capacitor configured to store a charge to produce the control voltage; first comparator means for monitoring the ternary output signal and for producing a trip signal when the amplitude of the ternary output signal exceeds a reference voltage; charge means for providing a first current to said capacitor in response to said trip signal; second comparator means for monitoring the ternary output signal and for producing a data present signal when the amplitude of the ternary output signal exceeds a data slice voltage; and discharge means for providing a second current to said capacitor in response to said data present signal, wherein said second current has a polarity opposite that of said first current.
Claim 11
Independent Claim
134 words
An apparatus for producing a control voltage for a digital baseband line equalizer having a ternary output signal, comprising: a capacitor configured to store a charge to produce the control voltage; first comparator means for monitoring the ternary output signal and for producing a trip signal when the amplitude of the ternary output signal exceeds a reference voltage; charge means for providing a first current to said capacitor in response to said trip signal; second comparator means for monitoring the ternary output signal and for producing a data present signal when the amplitude of the ternary output signal exceeds a data slice voltage; and discharge means for providing a second current to said capacitor in response to said data present signal, wherein said second current has a polarity opposite that of said first current.
Claim 12
Dependent Claim
113 words
The apparatus of claim 9, wherein said first comparator means comprises: a first comparator configured to compare the ternary output signal to a high reference voltage and to produce a high trip signal when the amplitude of the ternary output signal exceeds said high reference voltage; a second comparator configured to compare the ternary output signal to a low reference voltage and to produce a low trip signal when the amplitude of the ternary output signal exceeds said low reference voltage; and an OR gate coupled to said first and second comparators and configured to output said trip signal in response to one of said high trip signal and said low trip signal.
Claim 13
Dependent Claim
48 words
The apparatus of claim 10, wherein said charge means comprises: a first current source configured to produce said first current; and a first switch means connected in series with said first current source to selectively provide said first current to said capacitor in response to said trip signal.
Claim 14
Dependent Claim
118 words
The apparatus of claim 11, wherein said second comparator means comprises: a third comparator configured to compare the ternary output signal to a high slice voltage and to produce a data high present signal when the amplitude of the ternary output signal exceeds said high slice voltage; a fourth comparator configured to compare the ternary output signal to a low slice voltage and to produce a data low present signal when the amplitude of the ternary output signal exceeds said low slice voltage; and an OR gate coupled to said third and fourth comparators and configured to output said data present signal in response to one of said data high present signal and said data low present signal.
Claim 15
Dependent Claim
48 words
The apparatus of claim 12, wherein said discharge means comprises: a second current source configured to produce said second current; and second switch means connected in series with said second current source to selectively provide said second current to said capacitor in response to said data present signal.
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) | 1997-12-26 | 1998-06-27 | 1998-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-26 | 2002-06-27 | 2002-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-26 | 2006-06-27 | 2006-12-27 | $7700.00 | Window Closed / Lapsed |