US4792997A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Receiver for optical digital signals with dark current compensation
Assignee: Siemens AG
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Filing: 1987-06-17
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Granted: 1988-12-20
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Expires: 2007-06-17
Abstract
Abstract A receiver for optical digital signals has a transimpedance amplifier, the input of which is connected to an operating voltage via an active photodiode, and the output of which is connected to an input of a comparator. An operational amplifier is provided, the one input of which is connected to the input of the transimpedance amplifier, and the other input of which is connected to the operating voltage via a further, unilluminated photodiode. A reference voltage at the other input of the comparator is generated from the output voltage of the operational amplifier via a voltage divider.
Inventors
- 👤 Hans N. Toussaint
- 👤 Jan Goerne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:40
CPC Classifications
H; H04; H04B; H04B10/00; H04B10/60; H04B10/66; H04B10/69; H04B10/691; H04B10/6911; H03; H03F; H03F3/00; H03F3/04; H03F3/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
99 words
A receiver for optical digital signals, comprising: a transimpedance amplifier having an input connecting to an operating voltage via an active photodiode; an output of the transimpedance amplifier connecting to a first input of a comparator; an operational amplifier having a first input connected to said transimpedance amplifier input and a second input connected via an un-illuminated photodiode to said operating voltage; an output of the operational amplifier connecting through a voltage divider to a second input of said comparator; and said comparator connecting to an output whereby fluctuations in dark current occurring in the active photodiode are compensated.
Claim 2
Dependent Claim
99 words
A receiver for optical digital signals, comprising: a transimpedance amplifier having an input connecting to an operating voltage via an active photodiode; an output of the transimpedance amplifier connecting to a first input of a comparator; an operational amplifier having a first input connected to said transimpedance amplifier input and a second input connected via an un-illuminated photodiode to said operating voltage; an output of the operational amplifier connecting through a voltage divider to a second input of said comparator; and said comparator connecting to an output whereby fluctuations in dark current occurring in the active photodiode are compensated.
Claim 3
Dependent Claim
25 words
A receiver according to claim 1 wherein the active photodiode and un-illuminated photodiode are both integrated in a semiconductor chip and have substantially identical dimensions.
Claim 4
Dependent Claim
16 words
A receiver according to claim 1 wherein said un-illuminated photodiode is covered with a radiation-impermeable metallization.
Claim 5
Dependent Claim
97 words
A receiver for optical digital signals, comprising: a transimpedance amplifier having an input connecting to means for producing signals related to the digital signals; an output of the transimpedance amplifier connecting to a first input of a comparator; an operational amplifier having a first input connected to said transimpedance amplifier input and a second input connected to a reference photodiode means which is not modulated by said digital signals for producing a reference for dark current; an output of the operational amplifier connecting to a second input of said comparator; and said comparator connecting to an output.
Claim 6
Dependent Claim
97 words
A receiver for optical digital signals, comprising: a transimpedance amplifier having an input connecting to means for producing signals related to the digital signals; an output of the transimpedance amplifier connecting to a first input of a comparator; an operational amplifier having a first input connected to said transimpedance amplifier input and a second input connected to a reference photodiode means which is not modulated by said digital signals for producing a reference for dark current; an output of the operational amplifier connecting to a second input of said comparator; and said comparator connecting to an output.
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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) | 1991-12-20 | 1992-06-20 | 1992-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-12-20 | 1996-06-20 | 1996-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-12-20 | 2000-06-20 | 2000-12-20 | $7700.00 | Window Closed / Lapsed |