Claims
- 1. An optical receiver circuit for an incoming optical signal having broadband radio frequency amplitude modulation, said circuit comprising:
- an optical detector for receiving said optical signal and generating therefrom an electrical signal which varies with the optical signal power level;
- first means for amplifying said electrical signal;
- second means for amplifying said electrical signal;
- said first amplifying means and said second amplifying means each comprising a transimpedance amplifier stage including a first field effect transistor having a gate terminal, a drain terminal and a source terminal, each of said gate terminals being connected to a terminal of said optical detector and each drain terminal being connected to the gate terminal of the same field effect transistor through a selectable feedback resistor;
- means for coupling said first amplifying means and said second amplifying means in a push-pull relationship;
- said first amplifying means and said second amplifying means each further comprising a high impedance buffer amplifier stage having an input terminal connected to the drain terminal of its respective transimpedance amplifier stage and an output terminal connected to a terminal of said push-pull coupling means;
- a gain control circuit responsive to a control signal for varying a gain of said first amplifying means and second amplifying means; and
- wherein the high impedance buffer amplifier stages of said first and second amplifying means each comprise a second field effect transistor having a drain terminal connected to a terminal of said push-pull coupling means, a gate terminal connected to the drain terminal of said first field effect transistor and a source terminal connected to said gain control circuit.
- 2. An optical receiver in accordance with claim 1 wherein said gain control circuit comprises a pin diode.
- 3. An amplifier adapted to amplify a signal generated by an optical detector which varies with an optical signal power level applied to the detector, said amplifier comprising:
- first means for amplifying said signal;
- second means for amplifying said signal;
- said first amplifying means and said second amplifying means each comprising a transimpedance amplifier stage including a field effect transistor having a gate terminal, a drain terminal and a source terminal, each of said gate terminals being connected to an input terminal of said amplifier and each drain terminal being connected to the gate terminal of the same field effect transistor through a selectable feedback resistor;
- means for coupling said first amplifying means to said second amplifying means in a push-pull relationship;
- said first amplifying means and said second amplifying means each further comprising a high impedance buffer amplifier stage having an input terminal connected to the drain terminal of the respective transimpedance amplifier stage and an output terminal connected to a terminal of said push-pull coupling means;
- a gain control circuit responsive to a control signal for varying the gain of said first and second amplifying means; and
- wherein the high impedance buffer amplifier stages of said first and second amplifying means each comprise a second field effect transistor having a drain terminal connected to a terminal of said push-pull coupling means, a gate terminal connected to the drain of said first field effect transistor and a source terminal connected to said gain control circuit.
- 4. An optical receiver in accordance with claim 3 wherein said gain control circuit comprises a pin diode.
- 5. An optical receiver circuit for an incoming optical signal having broadband radio frequency amplitude modulation, said circuit comprising:
- an optical detector for receiving said optical signal and generating therefrom an electrical signal which varies with the optical signal power level;
- first means for amplifying said electrical signal;
- second means for amplifying said electrical signal;
- said first amplifying means and said second amplifying means each comprising a transimpedance amplifier stage including a first field effect transistor having a gate terminal, a drain terminal and a source terminal, each of said gate terminals being connected to a terminal of said optical detector and each drain terminal being connected to the gate terminal of the same field effect transistor through a selectable feedback resistor;
- means for coupling said first amplifying means and said second amplifying means in a push-pull relationship; and
- a gain control circuit responsive to a control signal for varying a gain of said first amplifying means and second amplifying means.
- 6. An optical receiver in accordance with claim 5 wherein said first amplifying means and said second amplifying means each further comprise:
- a high impedance buffer amplifier stage having an input terminal connected to the drain terminal of its respective transimpedance amplifier stage and an output terminal connected to a terminal of said push-pull connecting means.
- 7. An optical receiver in accordance with claim 6 wherein said push-pull connecting means comprises a transformer including:
- a primary winding having a first terminal at one end thereof connected to the output terminal of said first amplifying means, a second terminal at the other end thereof connected to the output terminal of said second amplifying means and a third terminal connecting an intermediate section of said secondary winding to ground through a DC blocking capacitor; and
- a secondary winding having output terminals adapted for connection to a CATV coaxial cable.
- 8. An amplifier adapted to amplify a signal generated by an optical detector which varies with an optical signal power level applied to the detector, said amplifier comprising:
- first means for amplifying said signal;
- second means for amplifying said signal;
- said first amplifying means and said second amplifying means each comprising a transimpedance amplifier stage including a field effect transistor having a gate terminal, a drain terminal and a source terminal, each of said gate terminals being connected to an input terminal of said amplifier and each drain terminal being connected to the gate terminal of the same field effect transistor through a selectable feedback resistor;
- means for coupling said first amplifying means to said second amplifying means in a push-pull relationship; and
- a gain control circuit responsive to a control signal for varying a gain of said first and second amplifying means.
- 9. The amplifier of claim 8 wherein said first amplifying means and said second amplifying means each further comprise:
- a high impedance buffer amplifier stage having an input terminal connected to the drain terminal of the respective transimpedance amplifier stage and an output terminal connected to a terminal of said push-pull connecting means.
- 10. The amplifier of claim 9 wherein said push-pull connecting means comprises a transformer including:
- a primary winding having a first terminal at one end thereof connected to the output terminal of said first amplifying means, a second terminal at the outer end thereof connected to the output terminal of said second amplifying means, and a third terminal connecting an intermediate portion of said secondary winding to ground through a DC blocking capacitor; and
- a secondary winding having output terminals adapted for connection to a CATV coaxial cable.
RELATED APPLICATIONS
This application is a continuation-in-part application of commonly assigned application Ser. No. 07/481,436, filed Sep. 3, 1991 which is a continuation-in-part Application of commonly assigned application Ser. No. 07/445,299, filed Dec. 1, 1989, now U.S. Pat. No. 4,998,012.
US Referenced Citations (32)
Foreign Referenced Citations (7)
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EPX |
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Non-Patent Literature Citations (2)
Entry |
Millman et al, "Integrated Electronics analog and digital circuits and systems" 1972 pp. 690-691. |
N. Kotera et al., "Laser Driver and Receiver Amplifiers for 2.4 Gb/s Optical Transmission Using WSi-Gate Ga As MESFET's" in GaAs IC Symposium Technical Digest 103-06 (Oct. 13, 1987). |
Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
481436 |
Sep 1991 |
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Parent |
445299 |
Dec 1989 |
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