450 results about "Limiting amplifier" patented technology

The invention discloses a 10G single-fiber bidirectional optical module, which comprises a burst laser driver, a burst light power indicator, a microcontroller, a single-fiber bidirectional optical device, an avalanche photoelectric diode bias control circuit, a limiting amplifier, a receiving end light power monitor and an SFP+ connector, wherein the microcontroller is mainly used for controlling the burst laser driver and the limiting amplifier; the single-fiber bidirectional optical device is connected between the burst laser driver and the limiting amplifier to realize conversion between electrical signals and light signals; and the avalanche photoelectric diode bias control circuit supplies a high bias voltage to a receiving end avalanche photoelectric diode and performs voltage compensation on the receiving end avalanche photoelectric diode according to the temperature property. The 10G single-fiber bidirectional optical module has the advantages of low design cost, simple circuit design and capability of meeting the requirement of a 10G EPON ONU symmetrical scheme.

A field effect transistor (FET) driver circuit includes an error amplifier for providing a FET control signal and a current limiting amplifier for preventing excessive current flow through the FET. The current limiting amplifier generates an overcurrent signal when an excessive current is detected. In response to the overcurrent signal, a voltage control circuit adjusts the voltage at the output of the error amplifier to turn off the FET. Meanwhile, a pulldown circuit at an input of the error amplifier adjusts the voltage provided to that input to cause the error amplifier to provide an output voltage that also tends to turn off the FET. If a buffer is present at that input to the error amplifier, a second pulldown circuit is placed at the input to the buffer to maintain a stable unity gain across the buffer.

The invention discloses an amplitude detection circuit with a direct current offset elimination function. The amplitude detection circuit has a differential structure, and consists of a direct current offset elimination circuit, an amplitude limiting amplification circuit, an amplitude detection circuit, a current addition circuit and a filtering circuit, wherein the direct current offset elimination circuit comprises a plurality of direct current offset suppressors with a low-pass filtering function; the amplitude limiting amplification circuit comprises a plurality of amplitude limiting amplifiers; and the amplitude detection circuit comprises a plurality of amplitude detection units. A differential radio frequency signal is amplified to be saturated by a plurality of stages of cascaded amplitude limiting amplifiers, the output of each stage of amplitude limiting amplifier is detected by the amplitude detection units, output detected amplitude values are transmitted to the current addition circuit for addition, and the sum is filtered by the low-pass filtering circuit to obtain output voltage related to the amplitude of the input signal. The circuit can be adapted to the requirements of high monolithic integration level of a radio frequency chip, and is applied to a high-integration level zero-intermediate frequency receiver with the requirement of signal amplitude detection.

An optical distributor includes an optical-signal input port, a light receiving device, a light emitting device, a light splitter, and optical signal output ports. The light receiving device converts an optical light signal input to the optical-signal input port into an electric signal. The light emitting device converts the electric signal into an optical signal. The optical splitter 14 splits the converted optical signal into two optical signals. The optical-signal output ports output the split optical signals. The light receiving device includes a light receiving element, a pre-amplifier, and a limiting amplifier. The light emitting device includes a light-source drive element and a light emitting element.

A modulated carrier signal is produced from a phase modulation signal in a phase locked loop in a polar modulator. This carrier signal is converted via a limiting amplifier to a square-wave signal, which is supplied to an amplifier. At the same time, an amplitude modulation signal at one input is connected to a control input of a controllable current source. The controllable current source is designed to emit a supply current at a current output as a function of the amplitude modulation signal at the control input. The current output of the controllable current source is connected to a supply input of the amplifier. The supply current for the amplifier is thus modulated on the basis of the amplitude information to be transmitted. The processing of the amplitude information within the current domain makes it possible to produce the polar modulator according to the invention as an integrated circuit, using CMOS technology.

A transimpedance amplifier (TIA) circuit usable for burst mode communications is provided. The TIA circuit includes a TIA stage, a limiter-amplifier, and a DC restoration loop. The invention overcomes problems of the prior art relating to burst communications, such as a DC level in the output signal which can change from burst to burst and a duty-cycle distortion in large signals. This is achieved by using a DC restoration loop that ensures achieving zero DC potential within variable acquisition periods.

The present invention discloses an optical module of an in-band pass through monitoring signal based on amplitude modulation, belonging to the field of communication technology. The optical module comprises a low speed baseband amplitude modulation circuit, a laser driving circuit, a laser, an electro-absorption signal modulation circuit, an electro-absorption modulator, an avalanche photodiode, a transconductance amplifier, an amplitude limiting amplifier, a mirror current circuit, and a low-frequency demodulation circuit. Compared with a conventional optical module, according to the optical module of the invention, a monitoring signal is loaded to the envelope of a bearing service signal through amplitude modulation and shares cable and channel resources with a bearing service signal, the channel resource is saved, the monitoring signal of the pass through is unrelated to a bearing service signal protocol, and the use flexibility is high. Since a low speed baseband signal amplitude modulation and demodulation unit is integrated in the optical module, the additional adding of an optical function unit is not needed, the pass through of the monitoring signal can be realized, and the optical module is a most cost-effective solution for an application scene with the need of monitoring signal transmission.

The invention discloses a nonlinear amplification-retransmission optimal power allocation method. The method comprises the following steps: an ideal amplitude-limiting amplifier model is constructed into a linear model with a Gaussian distortion noise option by using a linearized theory; according to the linear model, the chain equivalent single-to-noise rate of each nonlinear relay, devoted to a target receiver, is calculated; in order to obtain the optimal signal-to-noise rate performance, a maximum-combination-ratio receiver which is capable of realizing the nonlinear distortion is also designed; then, an optimal relay power allocation mathematical model is built, although the optimal power allocation problem is not a convex problem is found by analyzing a curve structure of signal to noise rate and power, the optimal relay power allocation problem can be converted into a convex optimization problem by limiting the maximum emission power; and finally, an optimal power allocation scheme is provided by utilizing a lagrangian multiplier method. A theoretical analysis and simulation result indicates that the method disclosed by the invention is superior to an optimal power allocation algorithm has no sense to nonlinear distortion, and has the capability of effectively improving the system capacity.

The invention discloses a dual-rate optical signal receiving device, which comprises a dual-rate optical receiving component, a dual-rate limiting amplifier circuit unit, and a data shunt unit. The dual-rate optical receiving component also comprises an optical detector and a dual-rate transimpedance amplifier; the dual-rate limiting amplifier circuit unit also comprises a dual-rate limiting amplifier; and the data shunt unit also comprises a 1:2 data fan-out device and a low-pass filter circuit. Due to the adoption of the technical scheme, through two optical signal receiving circuits formed by time division multiplexing on data at different rates, the received data is divided into two data channels at different rates through a data shunt device. Therefore, an easily realized physical layer solution is provided for the dual-rate time division multiplexed data.

The invention discloses a burst light signal receiving apparatus which comprises: a light receiving assembly and an amplitude limit amplifier circuit unit. The light receiving assembly further comprises: a photo-detector, a transimpedance amplifier, a direct current reservation circuit 1 and a direct current offset circuit. The amplitude limit amplifier circuit unit further comprises: a group of alternating current coupling capacitors, an amplitude limit amplifier and a direct current reservation circuit 2. By using a technical scheme of the invention, the input burst light signals in a certain dynamic scope can be returned to the available burst light signals in a short time. The technical scheme of the invention can be used in a burst light signal receiver of a XENPAK passive optical network (10 GEPON).

A device for detecting arc fault consists of current detector for detecting current variation and for generating its proportional signal, signal converter for limiting signal level, the first level limit amplifier, signal level detector for generating detection signal, pulse generator for forming normalization pulse, the first arc determining unit for counting pulse signal to judge whether arc is occurred or not and for generating arc detection signal, as well as breaker for cutting off wire when arc detection signal is generated.

The threshold voltage adjusting unit comprises: a feedback comparison module used for receiving the feedback quantity, and according to the variation of feedback quantity, determining the adjusting direction of the threshold voltage; a adjusting module used for getting the adjusted threshold voltage according to the adjusting direction of the threshold voltage and the adjusting step length; a D/A converter used for making D/A conversion for the threshold voltage and outputting the converted threshold. The invention can adjust the threshold voltage along with the variation of the signal and reduce the effects from noise to the threshold voltage so as to effectively reduce the error code rate.

The invention discloses a high-speed CMOS monolithic integration light receiver front end of a cross coupling structure. The high-speed CMOS monolithic integration light receiver front end comprises a photoelectric detector of a completely-symmetric structure, a trans-impedance amplifier of a difference structure, a direct current excursion eliminating unit, a three-stage sequence cascaded difference limiting amplifier and an output buffer stage; the trans-impedance amplifier of the difference structure is used for converting current signals output by the photoelectric detector into voltage signals and conducting preliminary amplification; the direct current excursion eliminating unit is used for eliminating direct current excursion led in by non-balanced signals at the input end of the trans-impedance amplifier and enables common mode levels at the output end of the trans-impedance amplifier to be coincident; the three-stage sequence cascaded difference limiting amplifier is used for amplifying the voltage signals output by the trans-impedance amplifier to be at the voltage level needed by a digital processing unit. Through the adoption of the cross coupling structure, the noise in-phase counteraction technology and the parallel type active inductor design, a high-speed and high-sensitivity standard CMOS monolithic integration light receiver can be achieved.

The invention discloses a dual-rate receiving device in an optical transceiver, which is suitable for the optical transceiver, and comprises a dual-rate optical receiving module, a dual-rate amplitude limiting amplifying circuit unit, a first rate amplitude limiting amplifier data path and a second rate amplitude limiting amplifier data path, wherein signals output by the dual-rate amplitude limiting amplifying circuit unit are respectively input into the first rate amplitude limiting amplifier data path and the second rate amplitude limiting amplifier data path so as to obtain data with different rates, and the data with the different rates are output to a system host machine. By using the technical scheme, the system host machine can receive data from the amplitude limiting amplifier data path with a corresponding working rate, has higher receiving sensitivity for high-rate and low-rate optical data signals and can receive optical signals formed by time division multiplex (TDM) for dual-rate data with lower cost.

A method and apparatus provides an input structure for a power amplifier. In one example, the input structure has an input network and a predriver circuit to provide an input signal to the power amplifier. The input network includes a transformer for helping to maintain a constant input impedance. The predriver includes a limiting amplifier that provides isolation between the power amplifier and the RF input. A DC feedback circuit is used by the predriver that maintains the DC level of the inverters to a desired level.

The invention discloses a passive optical network terminal which relates to the Ethernet passive optical network (EPON) technology. The novel passive optical network terminal integrates a photoelectric conversion circuit of a common optical network terminal and an MAC protocol processing circuit of the passive optical network into an SFP package. The self-contained MAC Ethernet passive optical network terminal SFP is characterized by comprising an optical transceiver BOSA (1), a laser driver LDD (3-1), a limiting amplifier LA (3-2), a PON protocol chip and peripheral circuit (4), an Ethernet serial parallel conversion chip SERDES (5), and a control unit MCU (2). The invention mainly protects the idea of integrating a common photoelectric conversion optical module and a PONMAC chip in the SFP package and realizes the circuit.

Embodiments of the present disclosure enable bandwidth extension of receiver front-end circuits without the use of inductors. As a result, significantly smaller and cheaper receiver implementations are made possible. In an embodiment, bandwidth extension is achieved by virtue of very small floating capacitors that are coupled around amplifier stages of the receiver front-end circuit. Each of the capacitors is configured to generate a negative capacitance for the preceding stage (e.g., equalizer or amplifier), thus extending the bandwidth of the preceding stage. A capacitively-degenerated cross-coupled transistor pair allows bandwidth extension for the final (e.g., amplifier) stage. Embodiments further enable DC offset compensation with the use of a digital feedback loop. The feedback loop can thus be turned on/off as needed, reducing power consumption.

The invention, which relates to the fiber optical communication technology field, discloses a small from-factor pluggable (SFP) module with low costs and a high precision digit diagnosis function. The invention aims at providing a SFP module which is with low costs and possesses a digital diagnosis function provided in a SFF-8472. The invention is characterized in that: using a single chip, which is integrated by a laser driver and a limiting amplifier, and cooperating with a controller unit so as to realize a high precision digit diagnosis function; accessing a filter between a light receiving interface component, the laser driver and the limiting amplifier of a limiting amplifier unit so as to improve sensitivity of the module and signal quality; adopting a applied resistor mode to a pin of a digital potentiometer of the controller unit so as to avoid a fault problem of nonluminescence when power is on. The SFP module can be used for a LC bi-directional single fiber SFP module, a SC bi-directional single fiber SFP module and a LC two fiber SFP module.