101results about How to "High tuning accuracy" patented technology

The three-port polarizing offset tunable optical filter based on TFF comprises a set or more tunable filter unit with one composed of optical ring connected to the multi channel optical signal input end, a thin film filter, the polarized beam divider A & B on the same light path on the back and forth of the thin film filter plate, featuring in the polarized beam divider A dividing input signal light dividing into P and S parallel lights, with P having half wave plate C rotating P into P-S, two parallel S lights reaching thin film filter plate whose normal line slants on the two parallel S light paths, half wave plate D rotating S into S-P, polarized beam divider B synthesizing P and S into ordinary light signal to output, reflective mirror E paralleling laid with thin film filter plate with reflective mirror F setting behind reflective mirror E with F vertically set with two parallel light paths. It is simple in structure, easy for realization, being able to eliminate polarized relative consumption and polarized light dividing.

There is provided a semiconductor device which can maintain a high tuning accuracy while suppressing a cost increase and suppress an increase in the time required for tuning. There are included, in addition to variable resistors configuring a level shift circuit, an additional resistor coupled between the output node of a VBGR voltage of a BGR circuit and one of the variable resistors and an additional resistor coupled between the other of the variable resistors and a reference voltage. N-channel MOS transistors are coupled in parallel with the additional resistors, respectively.

A digitally controlled filter tuning method and corresponding WLAN (Wireless Local Area Network) communication devices and integrated circuit chips are provided. A WLAN communication signal is filtered by a tunable filter. A cut-off frequency of the tunable filter is tuned by a feedback loop. Tuning the cut-off frequency includes comparing by a comparator an output signal emitted by the tunable filter to a reference signal and emitting by the comparator a comparator signal indicative of the difference between the output signal and the reference signal. Further, tuning the cut off frequency comprises receiving the comparator signal by a tuning controller and setting by the tuning controller the cut-off frequency of the tunable filter based on the comparator signal by applying a digital tuning word to the tunable filter. The described filter tuning technique may reduce product and manufacturing costs while providing enhanced tuning accuracy.

The invention discloses an automatic frequency tuning circuit of an active RC filter. The automatic frequency tuning circuit comprises comparators, a constant current source, a reference voltage generating circuit, a switched capacitor circuit and a digital logic control circuit. The automatic frequency tuning circuit is characterized in that the reference voltage generating circuit generates first reference voltage, second reference voltage and third reference voltage which are input to the first comparator, an operational amplifier and the second comparator respectively, voltage generated by the constant current source on the switched capacitor circuit is input to the operational amplifier, and the digital logic control circuit receives signals output by the first comparator and the second comparator, conducts operation treatment, outputs control codes to the switched capacitor circuit and adjusts the equivalent capacitance of the switched capacitor circuit. The automatic frequency tuning circuit is simple in implementation method, low in cost, small in volume, low in power consumption, high in tuning precision, good in application prospect and capable of being widely used in fields such as electronics and communication.

The invention provides a wavelength division-time division hybrid passive optical network system, which comprises a central office, a plurality of optical network units and a remote node, wherein the remote node is positioned between the central office and the plurality of optical network units; the central office is provided with a plurality of light sources for emitting downlink signal light of various wavelengths, a plurality of receivers for receiving uplink signal light emitted by the plurality of optical network units and transmitted by the remote node respectively, and a plurality of multiplexer / demultiplexers for multiplexing and demultiplexing the downlink signal light and the uplink signal light; the remote end node is used for multiplexing the downlink signal light from the central office and demultiplexing the uplink signal light from the optical network units; and each optical network unit is provided with an internal annular coupler, a light separating unit for separating downlink signal light into signal light and injection light, a downlink data receiver for receiving separated signal light, and an MEMS (Micro Electro Mechanical System) tunable laser for receiving injection light and generating uplink signal light.

The invention provides a frequency tuning method for a TeraHertz parameter oscillator, which can realize high precision continuous tuning output of coherent narrow band TeraHertz by continuously changing pumping wavelength of the TeraHertz parameter oscillator without changing the incident angle of the pumping light. The invention has high frequency tuning precision (in particular in the long wavelength part), can overcome the change of characteristic of TeraHertz parameter oscillator caused by the change in the action area of the triple waves, can obviously expand frequency tuning scope of the TeraHertz parameter oscillator together with the angle tuning technology, and is hopeful to reach the low frequency area far smaller than 1THz which is hard to reach by singly using the angle tuning technology. Based on the tuning technology, the TeraHertz parameter oscillator can be widely used in TeraHertz optoelectronic technical fields such as medical diagnosis, fine spectrum analysis, bio-medical imaging, TeraHertz communication and the like.

The invention discloses a tunable true time delay test device and method based on discrete chirped fiber gratings. Light emitted by a tunable laser and a fixed wavelength laser at the same time enters a discrete chirped fiber grating time delay unit composed of uniform fiber gratings and linear discrete chirped fiber gratings successively in two times after microwave signal modulation so as to complete two-stage time delay, and four paths of electric signals with equal time delay difference are output at last; and meanwhile, the output wavelength of the tunable laser and the tunable linear fiber gratings are synchronously tuned to realize the change of the time delay difference. By adoption of the tunable true time delay test device and method disclosed by the invention, the output of four paths of signals with equal time delay difference and fine tuning can be realized, the instantaneity is good, although a path of error sources is imported, the system can neglect the error sources by means of smart combination of the linear chirped fiber gratings, meanwhile the test device is simplified, and the cost is reduced.

The invention discloses a transmitting-end dynamic tuning device and method based on double DC-DC converters. A transmitting end comprises a DC power supply E, a DC-DC converter DA, a full-bridge inverter NA, a transmitting-end compensation network TC and a transmitting coil Lp, wherein the DC power supply E, the DC-DC converter DA, the full-bridge inverter NA, the transmitting-end compensation network TC and the transmitting coil Lp are connected sequentially. A receiving end comprises a receiving coil Ls, a receiving end compensation network RC, a rectifier bridge Z, a load Z and a DC filtering capacitor Cd, wherein the receiving coil Ls, the receiving end compensation network RC, the rectifier bridge Z, the load Z and the DC filtering capacitor Cd are connected sequentially, and the DCfiltering capacitor Cd is connected to two ends of the load RZ in a parallel manner. The dynamic tuning device comprises a DC / DC converter DB, a full-bridge inverter NB, and a transformer. The beneficial effects of the invention are that the phases of the output voltage and current of the inverter are directly measured, so as to judge the resonant state of the transmitting end, so the device is simple and effective, and is good in real-time performance; the tuning device enables the output of the full-bridge inverter NB to remain resistive, reduces the reactive power of a system, can reduce the capacity of a power supply through resonance adjustment, can achieve real-time tuning, is high in tuning precision, and enables the transmitting end to be closer to an ideal resonant state; the device enables the output voltage to achieve the closed-loop control and maintains the constant-voltage output through the DC / DC converter.

The invention relates to a filtering device with adjustable central wavelengths. The filtering device is composed of a narrow bandpass filter, a clamp, a pressing ring, a heat preservation cover, a heat preservation cover cap, a thermistor, a first heat preservation lens, a second heat preservation lens, a servo turntable, a heating resistor, a light splitter mirror, a wavelength meter and a controller. The filtering device is high in adaptive capacity to the environment, can normally work under the condition that temperature fluctuation is large, has the advantages of being simple in structure, convenient to operate and high in central wavelength tuning accuracy, and can be applied to an optical system with strict requirements for the spectrum central wavelengths under the temperature alternating condition.