Abstract:
Low phase noise radio frequency (RF) sources generated by voltage controlled oscillators (VCOs) are described. Optical modulators driven by a VCO may be used to generate optical side-bands to cw lasers. The spectral extent of said side-bands can be increased via frequency broadening in highly nonlinear waveguides. Free running mode locked low phase noise comb oscillators can be used as reference oscillators to generate beat signals between those side-bands and individual comb modes at distal spectral regions, thereby creating an error signal used to reduce the phase noise of VCOs and the generation of low phase noise RF signals. VCO phase noise may be reduced by using free-running modelocked comb lasers phase locked to external frequency references, by omitting a reference comb and using a nonlinear interferometer for generating an error signal, or by locking a slave comb to the modulation frequency of an intra-cavity modulator driven by the VCO.
Abstract:
L'invention concerne un récepteur d'un signal lumineux impulsionnel qui comprend : - une photodiode (1) apte à générer un courant électrique (I D ) en réponse à ce signal lumineux, ayant comme caractéristique une capacité C d , - une masse électrique, - un amplificateur transimpédance (2) relié en entrée de la photodiode par une capacité de liaison C liaison . Il comporte un plot d'atténuation (30) situé entre la photodiode et l'amplificateur transimpédance, constitué d'une capacité C p avec C p =C d /(α-1 ), a étant une atténuation prédéterminée avec a >1.
Abstract:
In at least some examples, a communication device includes a photo-diode to convert an optical signal into an electrical current and a feedback-based trans-impedance amplifier to amplify the electrical current. The communication device also includes a transmission line between the photo-diode and the feedback-based trans-impedance amplifier. The feedback-based trans-impedance amplifier includes a programmable input impedance that has been matched to an impedance of the transmission line.
Abstract:
In accordance with an embodiment, a 4T pixel includes a first switch having a control terminal and first and second current carrying terminals and an amplifier having an input terminal and an output terminal. A second switch is coupled between the first switch and the amplifier.
Abstract:
Provided herein are optical sensor systems that can be used for ambient light detection, proximity detection and motion detection, as well as to larger systems that include such an optical sensor system, and to related methods. In an embodiment, the optical sensor system includes a front end, an ambient light channel, a proximity channel and a motion channel. In an embodiment, offset and gain of the proximity channel is adjusted based on motion detected by the motion channel.
Abstract:
An apparatus includes an electronic amplifier and an electrical feedback line, a plurality of electrical sources, and an electronic controller. The electrical feedback line connects an output of the electronic amplifier to an input thereof. The electrical sources connect to nodes on the electronic feedback line. The electronic controller is configured to adjust the electrical sources in a manner responsive to a current input to the electrical feedback line.
Abstract:
A transimpedance amplifier (100) is provided including an input, an amplifier and a non-linear limiting circuit. The input is configured to provide an input current (Iin) which includes a logic high range between a minimum input current and a maximum input current for logic high. The input current also includes a range of knee values. The amplifier is configured to generate an output voltage having a range between a first voltage and a second voltage. The non-linear limiting circuit includes a first current source, a first diode connected transistor, a second diode connected transistor, and a second current source. The first diode connected transistor (40) is prebiased to generate a first base-to-emitter voltage when the input current is approximately zero. The first diode connected transistor is configured to begin limiting the range of the output voltage (Vout) at a selected knee value, which is slightly greater than the minimum input current for logic high, by changing the first base-to-emitter voltage when the input current reaches the selected knee value of the input current.