82 results about "Preselector" patented technology

A GPS receiver circuit (300) for reducing insertion loss. The receiver circuit (300) includes a switch (304) for diverting input signals between a filtered pathway (312) and a short circuit pathway (310) to an amplifier (314). The amplifier (314) output feeds an automatic gain controller (316) that senses a noise level in the output of the amplifier (314) and adjusts a gain of the amplifier (314) in response to the noise level. The receiver circuit (300) also includes a threshold detector (306) with an input coupled to the output of the automatic gain controller (316) and an output coupled to the switch (304) for selecting between the filtered pathway (312) and the short circuit pathway (310), thereby removing the filter (312) from the signal path if not needed.

A transponder receiver for detecting different radio frequency (RF) interrogation mode signals having relatively wide and narrow bandwidths about a common RF center or carrier frequency. A front end stage of the receiver has a preselector with a wide band RF filter for passing both of the wide and the narrow bandwidth interrogation mode signals about the RF center frequency, and a mixer for converting signals from the preselector to frequencies within an intermediate frequency (IF) band. A first IF channel has a narrow band IF filter with a pass band sufficiently wide to pass first IF signals corresponding to the narrow bandwidth interrogation mode signals, but to reject signals corresponding to undesired interfering signals at frequencies near the narrow bandwidth interrogation mode signals. A second IF channel has a wide band IF filter with a pass band sufficiently wide to pass second IF signals corresponding to the desired wide bandwidth interrogation mode signals. The receiver may be incorporated in a transponder for operation in narrow IFF Modes 1-4, C and S, and in wide IFF Mode 5, with optimum performance in all modes.

A preselector amplifier system and method including of various components is described. The various components may include a vector generator, an active power splitter, an active power combiner, or the like. The preselector amplifier may be integral to and/or coupled to a communications system. The communications system may be at least one of a transceiver, receiver and/or transmitter. The communications system may transmit radio frequency (RF) signals.

The invention discloses a device and a method for synchronizing system frequency in a packet transport network, and relates to a packet transport network in optical communication. The system frequency synchronizing device comprises a microcomputer processor, a field programmable gate array (FPGA) processing module, a clock integrated circuit, a packet transport network service disk, a synchronous state byte extracting module, a synchronous state byte generating module, a phase locked loop circuit, an external clock input circuit, a high stable crystal oscillator, a clock distributing circuit, a HDB3 coding module and an external clock output circuit, wherein the FPGA processing module comprises a preceding stage preselector, a priority level control module, a first selector, a second selector and a third selector. By the device and method, the system frequency in the whole packet transport network can be synchronized rapidly, data business package transmission and smooth transition can be carried out rapidly and hierarchically, and the device is flexible and has high reliability.

The invention discloses a signal analysis device which comprises a preselector module, a fundamental wave frequency mixing module, a harmonic frequency mixing module, a local oscillator module, a data acquisition and processing module and a PC (Personal Computer) machine, wherein the preselector module is used for shunting signals of which frequencies are over a preset frequency threshold A according to the frequencies, respectively feeding the signals into the fundamental wave frequency mixing module and the harmonic frequency mixing module to carry out processing and converting the frequencies of the signals into required frequencies; the local oscillator module is used for providing local oscillator signals for the fundamental wave frequency mixing module and the harmonic frequency mixing module; the data acquisition and processing module is used for carrying out data acquisition and processing operation on the received signals; and the PC machine is used for controlling the modules through PXIe (Pci Express-extensions-for-instrumentation) buses. By the technical scheme disclosed by the invention, the problems of single function of a signal analysis instrument and incompatibility of instruments of different manufacturers in the prior art can be solved. The invention also discloses a method for configurating the signal analysis device.

The invention belongs to the technical field of signal processing, and relates to a device and method for achieving the spread spectrum function of a spectrum analyzer. The device comprises a waveguide adaptor, a first waveguide switch, a second waveguide switch, a high-pass filter, a low-pass filter, a fundamental wave mixer, a dot frequency local oscillator and an intermediate frequency filter amplifier. The method includes the steps that firstly, FIF of the intermediate frequency range of a spread spectrum device is defined according to the coverage area of a preselector of a host, and then FLO of frequency of the dot frequency local oscillator is configured according to FRF of the frequency range of the device and the FIF; secondly, the design of the filters is optimized, wavebands are divided, the frequency conversion formula (FRF-FLO) is used for a low-frequency band, and the low-pass filter is matched; the frequency conversion formula (FLO-FRF) is used for a high-frequency band, and the high-pass filter is matched, and then the spread spectrum function of the spectrum analyzer is comprehensively achieved. According to the device and method, when the frequency range is higher than 67GHz, the spread spectrum function of the spectrum analyzer for image signal curbing can be also achieved.

The invention relates to a step switch provided with a preselector and a polarity circuit, a separate polarization resistance being respectively provided at the beginning and the end of the stepped winding. Optionally, the two polarization resistances can be connected continuously or via separate polarity switches.

A measuring receiver comprises a spectrum analyzer having a local oscillator for sweeping the measurement frequency of the spectrum analyzer through multiple frequency bands. A preselector has multiple filter paths with frequency bands corresponding to frequency bands of the spectrum analyzer. The filter paths for passing signals through the preselector and outputting filtered signals to the spectrum analyzer. Switches of the preselector switch between filter paths to switch in a filter path having a frequency band corresponding to a frequency band being swept by the spectrum analyzer. A controller delays the sweeping of the measurement frequency during intervals when the switches are switching between filter paths.

A regulation-free coupling structure of a high-temperature super conduction filter used in satellite communication characterizes in inserting sections of L transmission lines in the same process technology with the resonator and tap and finished at one run in a suitable place between two resonators connected by wires at both sides of a bandpass filter and another resonator slantly opposite to them suitable for the design of frequency preselector of satellite receiving system RF front end or the base station front end in mobile communication system. Reflection loss in pass-band reduces to -20dB from original-15dB and transmission efficiency S21 is improved.

The invention relates to a heavy truck transmission with main and auxiliary box structures and a single H gate valve for the transmission. On the basis of an existing heavy truck transmission with the main and auxiliary box structures, a brand-new gas path is adopted, a double-H valve is canceled, a gas path control valve and the single H gate valve are additionally arranged for jointly controlling the gas path, the gas path control valve is used for controlling on and off of a high-gear gas path, the single H gate valve is used for controlling conversion of a high gear and a low gear, and a conversion switch is integrated in a preselector valve, so that the operation is simpler and clearer, and the probability of mis-operation of gear engaging is greatly reduced; meanwhile, the structure of an operation device can be simplified, and the assembling difficulty is reduced. The single H gate valve is mainly applied to an 8-speed transmission and a 9-speed transmission of an applicant, the gear shift comfortableness and the operation reliability are greatly improved.

The invention provides a frequency-selective electromagnetic radiation monitor. The frequency-selective electromagnetic radiation monitor includes a host machine and an antenna which are connected with each other; the antenna is used for receiving spatial electromagnetic radiation signals; the host machine comprises a preselector, a radio frequency unit, an analog-to-digital converter, a data processing unit and a main control unit which are connected with one another sequentially; the antenna is connected with the preselector; the preselector includes a plurality of radio frequency filters which are in parallel connection; the plurality of radio frequency filters are used for filtering the electromagnetic radiation signals received by the antenna so as to obtain electromagnetic radiation signals of a preset frequency; the radio frequency unit comprises an amplifier and a high-pass filter connected with the amplifier, wherein the amplifier is connected with the radio frequency filters, and the high-pass filter is connected with the analog-to-digital converter. The frequency-selective electromagnetic radiation monitor of the invention can evaluate measured electromagnetic field signals based on frequencies and meet the requirement of the GB8702-2014 ''controlling limits for electromagnetic environment''.

According to the ultra-wideband constant-temperature down converter disclosed by the invention, down conversion can be carried out on a radio frequency signal of 200 MHz - 12 GHz to an intermediate frequency signal of 1.2 GHz +/-250 MHz. According to the technical scheme, a control unit collects the state of each functional unit and issues the state to each functional unit; a frequency synthesizer unit generates a local oscillator signal LO required by the equipment according to the frequency issued by the control unit; a receiving channel unit carries out frequency spectrum mixing, preselector group filtering and amplification processing on a local oscillation signal LO generated by a frequency synthesizer unit frequency converter local oscillation source and an external high-low frequency band radio frequency signal RF, through at least two-stage frequency conversion, under the control of an FPGA, down-conversion is carried out to obtain an intermediate frequency signal, and a heat dissipation unit carries out heat dissipation and cooling treatment according to a control command issued by the control unit, so that the frequency converter works in a constant temperature range.

A preselector forms a plurality of preselections, by generating, for each preselection, a predetermined number of random locations, each location being for an antenna element of the predetermined number of antenna elements around a device under test in an over-the-air test. A selector selects, for at least one path of a radio channel to be simulated, a preselection from among the plurality of preselections for which an absolute error between a theoretical and real spatial correlation is below a predetermined threshold. A connector connects the antenna elements at the locations of the selected preselection and the radio channel emulator together for physically realizing the simulated radio channel for the device under test and the radio channel emulator.

The invention provides a broadband preselection mixer design method. Through preferable ferrite harmonic oscillator of a preselector and by utilizing high-saturation magnetization intensity characteristic of a NZF ball to broaden the passband bandwidth, the 3dB bandwidth can reach 300 MHz-500MHz. By adopting the above scheme, the influence of preselector passband offset on overall performances of a frequency spectrograph due to the inherent characteristics, such as hysteresis lag, temperature drift, and tuning nonlinearity and the like, of a magnetic device is effectively reduced; by adopting optimization coupling structure and magnetic circuit design and the like methods, the frequency range of the preselector is broadened to be 26.5 GHz-50 GHz; high and low local oscillator schemes are applied simultaneously, the design difficulty of a local oscillator Balun is reduced; a double-balanced mixer with third harmonic frequency mixing covering full waveband is established, and finally a broadband preselection mixer, of which the frequency range covers 26.5 GHz-50 GHz is designed.

A dynamic model of non-linear tuning behavior is used to tune a tunable device. The model quantifies a difference between a tuning characteristic of an ideal device and an actual tuning characteristic of the device. The model adjusts the tuning according to the difference. A method of compensated tuning of tunable device comprises employing a dynamic model of the tunable device to produce a compensated tuning control input to the tunable device during tuning. A tuning compensator for a tunable device comprises the dynamic model that is employed with an input tuning command to generate a compensated tuning command. A tuning-compensated YTF comprises a dynamic model-based tuning compensator and a YTF. A spectrum analyzer having a tuning-compensated preselector comprises a YTF preselector, a frequency converter, a video signal processor unit, a tuning compensator, and a controller. The tuning compensator uses the dynamic model to tune the preselector.

The invention relates to an interlocking speed limit control system of a refueling truck, which belongs to the technical field of a special purpose vehicle. An outlet end of a parking interlocking magnetic valve of the system is led to a controlled end of an interlocking control pneumatic control valve, and is connected with a double-cavity brake chamber at the same time; an outlet end of a preselector valve is led to a variable-speed controlled end of a gearbox, and is also led to a controlled end of a top assembling neutral position control pneumatic control valve, and an outlet end of the top assembling neutral position control pneumatic control valve is led to a neutral position controlled end of the gearbox. In addition, the interlocking speed limit control system of the refueling truck also comprises a parking interlocking override switch valve provided with a first outlet end and a second outlet end, an inlet end of the parking interlocking override switch valve is connected with the outlet end of the preselector valve in parallel, the first outlet end is led to a hand brake valve, and the second outlet end is led to the variable-speed controlled end of the gearbox, and simultaneously is led to an inlet end of the top assembling neutral position control pneumatic control valve. According to the invention, the abnormal movement of a vehicle caused by nonstandard operation is effectively avoided, a quick reaction capability under a condition of emergency evacuation is provided for the system, the speed limit control when the vehicle is driven in a field is provided at the same time, and the control function is more comprehensive.

The invention relates to a two-stage frequency conversion broadband receiver, which relates to the technical field of electronics and aims to resolve technical problems that a traditional product is not high in integrated level and frequency stability, poor in phase noise and spurious signal suppression, not high in stability and the like. The two-stage frequency conversion broadband receiver is a two-stage frequency conversion structure, a preselector filter group consists of a first filter 2 and a second filter 3, an RF (radio frequency) inputting radio frequency signal passes through a limiter I and the preselector filter group, modes of the RF inputting radio frequency signal are selected after the RF inputting radio frequency signal passes through the preselector filter group, then twice frequency conversion is carried out, the signal is amplified in a filtered manner in frequency conversion processes, and finally, an intermediate-frequency signal with the frequency of 70MHz is outputted.

The invention belongs to the technical field of digital tuning frequency hopping communication, and discloses a shortwave pre-post selector, which is high in frequency hopping speed, stable and reliable to work and is stable to realize higher selectivity; the shortwave pre-post selector is arranged in a shortwave radio station, and a pre-selector signal input end, a post selector signal input end, a pre-selector signal output end and a post selector signal output end are arranged on the shortwave pre-post selector; and the shortwave pre-post selector comprises a control unit, an amplitude limiting protection unit, a first transmitting-receiving conversion unit, a first wave band conversion unit, a first resonant unit, an amplifying unit, a second resonant unit, a second wave band conversion unit and a second transmitting-receiving conversion unit.

A method for measuring composite distortion levels using a coherent multicarrier RF signal generator having incrementally related frequencies is disclosed. The invention provides for the use of a coherent multicarrier signal generator that permits arbitrary RF carrier phase control on an individual carrier basis in order to enable sequential distortion measurements under varying carrier phase conditions. In order to obtain measurement results that match those obtained by the use of prior art non-coherent signal sources, the present invention provides for averaging of distortion measurement results over a 'phase configuration ensemble' that is obtained by multiple sequential measurements, in which the individual carrier phases for each measurement are preselected at random. The advantages afforded by the invention in comparison with prior art methods are improved repeatability and accuracy, reduction of the required measurement resolution bandwidths (from 30 kHz to as low as 30 Hz) thereby the reduction of noise levels by 30 dB. This feature greatly improves the measurement system's dynamic range and permits the elimination of overload protection preselector filters that are commonly used in prior art non-coherent measurement systems.

The invention discloses a small short-wave preselector, which comprises a basic resonant circuit preceding stage, a basic resonant circuit backward stage, a low-noise amplification circuit, a switching diode capacitor array, a triode driving circuit, a singlechip main control circuit and radio frequency signal channel gating switches, wherein an input radio frequency signal passes through a first radio frequency signal channel gating switch and then is transmitted to the basic resonant circuit preceding stage for frequency selection, and a useful signal is output; and the useful signal is amplified by the low-noise amplification circuit and subjected to frequency selection output through the basic resonant circuit backward stage and a second radio frequency signal channel gating switch. According to the small short-wave preselector provided by the invention, in a filtering system module of a receiver, a useless signal near a required frequency can be suppressed, and the sensitivity of the receiver is improved.

The invention discloses a short wave transmit-receive digital signal processing circuit based on a CPCI bus. The short wave transmit-receive digital signal processing circuit comprises one FPGA chip and one DSP chip. The FPGA chip is in communication connection with the DSP chip, the DSP chip is provided with a CPCI bus interface, the FPGA chip is used for achieving logic control inside the circuit, up-down frequency conversion of multiple paths of signals, filtering processing and outward interface control, and a DSP is used for achieving signal processing of a transmit-receive channel, controlling a candidate device, a power amplifier and antenna regulation of a transmitter end according to a control protocol of a transmitter and controlling a preselector of a receiver according to a control protocol of the receiver. The short wave transmit-receive digital signal processing circuit based on the CPCI bus can synthesize transmit-receive functions in one circuit.