61results about How to "Prevent self-oscillation" patented technology

The present invention provides a receiving/transmitting switching device which is used for realizing the receiving/transmitting switching of the TDD wireless communication system. The receiving/transmitting switching device comprises a power amplifier, a low-noise amplifier and a circulator, and also comprises the following components: a quarter-wave microstrip which is used for impedance conversion and has a first end connected to the third port of the circulator and a second end connected to the input end of the low-noise amplifier; a first switching element which has a negative pole connected to the third port of the circulator and a positive pole connected to the first end of the inductor; a second switching element which has a negative pole connected to the second end of the quarter-wave microstrip and a negative pole earthed; a load resistor which absorbs the reflected wave of the transmitted signal and the leakage signal of the circulator and coverts to heat energy, wherein the first end of the load resistor is connected to the positive pole of the first switching element and the second end is earthed; and an inductor which operates a high resistance function to the radio frequency through the direct current bias thereby guaranteeing that the low-noise amplifier will not be damaged by the large signal at any working time.

A first drive control signal regenerating circuit outputs an ON timing drive signal at turn-ON of a main switch element, and a second drive control signal regenerating circuit generates an OFF timing drive signal at turn-OFF of the main switch element. A rectifying switch controlling switch element connected between the gate and source of a rectifying switch element is driven by an output of the second drive control signal regenerating circuit. An output of the first drive control signal regenerating circuit connects to the gate of a commutating switch controlling switch element, which connects to one end of an auxiliary winding, the other end thereof being connected to the gate of a commutating switch element. Accordingly, the rectifying switch element is directly controlled from the primary side.

The circuit includes power amplifier to amplify emission signal up to emission power, circulator to couple its first port with the amplifier for exporting amplifier output power to the second port of the circulator in order to let antenna emit it, low noise amplifier to couple with circulator third port to receive signal inputted from the second port of the circulator through receiving antenna and to amplify the received signal, control unit consisting of actuating circuits for the power amplifier and the low noise amplifier to cut off the power amplifier at the time of receiving signal and to cut off the low noise amplifier at the time of emitting signal.

There is provided a flay-back type synchronous rectifying switching power supply device in which a rectifying element is surely turned off before the main switch is turned on even when the on-time of a main switch element is lengthened due to sudden variation of a load. The synchronous rectifying switching power supply device is equipped with a synchronous rectifying element (Q 2 ) connected to a secondary winding (N 2 ) of a transformer (T) in series and driving means comprising an auxiliary winding (N 3 ), etc. for turning on the synchronous rectifying element (Q 2 ) complementarily with a main switch element (Q 1 ) between output terminals ( 13, 14 ). A transistor (Tr 1 ) serving as interrupting means for turning off the synchronous rectifying element (Q 2 ) is provided between the gate and source of the synchronous rectifying element (Q 2 ). An off-timing at which the synchronous rectifying element (Q 2 ) is turned off by the interrupting means (Tr 1 ) is set within a timing range which corresponds to a fixed time after the main switch element (Q 1 ) is turned on and also is as near as a fixed driving period of the main switch element (Q 1 ).

The invention relates to a Rogowski coil for measuring nanosecond pulse current. The Rogowski coil comprises an ultracrystalline magnetic core and a copper belt wound on the ultracrystalline magnetic core. And the ultracrystalline magnetic core and the copper belt are arranged in an annular shielding outer shell; an integrating resistor is formed by connecting a plurality of carbon film resistors in parallel, and the carbon film resistors connected in parallel are arranged in the shielding outer shell. The Rogowski coil for measuring nanosecond pulse current can measure the nanosecond pulse current, the test effect of the Rogowski coil is good in actual use, the Rogowski coil can maximumly test current pulses with the leading edge being several nanoseconds, and current amplitude of several kilo-amperes can be measured.

The invention relates to a device and method for suppressing earth leakage and common-mode interference of a cable of a differential resistance sensor. The device comprises a controllable constant current differential excitation circuit, an error amplification circuit and a differential measurement circuit which are connected in sequence, the controllable constant current differential excitation circuit is an excitation and differential measurement circuit with high impedance characteristic relative to the ground, so that influence of residual ground noise interference is presented as common-mode interference; residual common-mode interference is removed by the high common-mode rejection ratio characteristic of the differential measurement circuit; and the voltage between the potential value of the common end of the two resistor arms of the differential resistance sensor and the ground potential is forced to be almost zero through the error amplification circuit. Thus, the current flowing through the earth leakage impedance of the cable core is almost zero, the leakage current and the noise interference current are greatly reduced, the current flowing through the two resistor armsof the differential resistance sensor is ensured to be equal to each other to the greatest extent, and the accuracy of a resistance ratio measurement value is ensured.

The invention provides a spatial field power supply suitable for a Sipm (Si photomultiplier). The spatial field power supply suitable for the Sipm comprises a flyback power conversion topology, a rectifying and filtering circuit, an operational amplifier, a DA chip, a PNP type triode, and an NPN type triode; the operational amplifier, the DA chip, and the triodes form a linear adjustment circuit,low voltage at an input end is converted into high voltage through the flyback power conversion topology, then the high voltage is taken as input of the linear adjusting circuit after being subjectedto filtration through the rectifying and filtering circuit, current flowing through the triodes is controlled by utilizing the DA chip and the operational amplifier, the linear amplification characteristic of the triodes is utilized at the output end, and linearly adjustable high voltage is outputted from the output end of the linear adjustment circuit. The spatial field power supply suitable forthe Sipm realizes continuously adjustable and wide-ranged high voltage output.

The invention relates to large-energy laser impulse amplification system with saturated absorption body, which comprises a laser oscillator, an amplifier, and said body on light path between oscillator and amplifier with opposite wave length as laser. This invention overcomes the problem that system has huge volume and can not prevent interstage couple and eliminate impulse bottom noise synchronously.

The invention discloses a dual-gradually-changed transitional waveguide applied to a millimeter and higher frequency point coupled cavity traveling-wave tube. The transitional waveguide is equipped with a first port and a second port, wherein the width L1 of the first port is greater than the width L3 of the second port; and the height L2 of the first port is greater than the height L4 of the second port. By adoption of the transitional waveguide, the reflection of the waveguide input end and the waveguide output end is effectively restrained, and self-oscillation caused by matching defects is overcome.

The invention relates to a slab laser amplifier and a laser output method. The slab laser amplifier comprises a gain dielectric module, pumping modules, and a reflector module, wherein the reflector module comprises two reflectors which are located on the left and right sides of the gain dielectric module; the pumping modules are located on the front and rear sides of the gain medium module; laser crystals are 0.5-1.5mm thick and include one doped laser crystal and two non-doped laser crystals; the two non-doped laser crystals are bonded to the two long and high surfaces of the doped laser crystal without adhesive, respectively, and arranged in parallel with the doped laser crystal; after seed laser is incident into the laser crystals at a certain angle, the seed laser is reflected back and forth between the reflectors, and meanwhile, passes through the laser crystals between the reflectors, and finally, the power amplified laser can be output. The bonded laser crystals of an ultrathin slab structure are taken as the gain dielectric of the slab laser amplifier, the thermal effect of the laser crystals is reduced and the gain effect of the gain dielectric is improved; high-output power and high-beam quality continuous or pulse laser amplified output can be obtained.

The invention provides a resonant cavity and a terahertz extended interaction oscillator of a cross structure. The terahertz extended interaction oscillator of the cross structure is greatly differentfrom a traditional terahertz extended interaction oscillator. In a conventional device, a longitudinal electric field is distributed in one direction (such as an x-direction or a y-direction) in a concentrated manner; while a longitudinal electric field is distributed in two directions (i.e., the x-direction and the y-direction) at the same time in the device of the cross structure. Therefore, inthe structure, the energy exchange efficiency of the longitudinal electric field and the cylindrical electron beam can be effectively enhanced, and the output power can be effectively improved. The device can work under the working conditions of 14kV and 0.1 by optimally designing the cross extended interaction oscillator working at 0.3 THz, and the power output of about 51.5 W can be realized. The cross structure is suitable for improving the output power of the terahertz extended interaction oscillator, and is particularly suitable for improving the engineering realizability and the workingstability of a device under lower working current.

The invention discloses a high-energy 1.0[mu]m laser amplification system with 100ns pulse width. The system employs a 1.0[mu]m DFB semiconductor laser as a seed source so as to obtain high-stabilitysingle-frequency laser output. The system utilizes an optical fiber amplification module for chopping, the continuous seed source is chopped into pulse laser with a Lorentz waveform rising edge through an acoustic optical modulator, and finally the width of laser pulse is continuously widened through the amplification effect of a rear-stage solid amplification module, so that 1.0[mu]m pulse laserwith the pulse width greater than 100ns is obtained. According to the invention, the single frequency and stability of 1.0[mu]m laser are ensured, and a new technical route is provided for coherent detection radar to adopt a 1.0[mu]m laser light source through the characteristic that the laser pulse width is gradually broadened through the laser amplification effect.

The invention provides a resonance suppression method for a humanoid flexible arm, particularly provides a resonance suppression method for a humanoid flexible arm based on a PR controller, and belongs to the field of vibration control. An output shaft of a joint motor end of the humanoid flexible arm is connected with a fixed end of an arm connecting rod through a harmonic reducer, and the inherent flexibility of a flexible gear of the harmonic reducer introduces a resonance frequency point to cause the resonance problem of the humanoid robot arm. According to the resonance suppression methodfor the humanoid flexible arm, the PR controller is introduced into a control system of the humanoid flexible arm, the disturbance suppression capability of the PR controller at a specific frequencypoint is utilized, so that the resonance caused by the fact that the output signal frequency of the controller is equal to the resonance frequency of the humanoid flexible arm is avoided, and the operation performance and the stability of the humanoid flexible arm are improved.

The invention is applicable to the technical field of electric control, and particularly provides a control method for preventing abnormal manual steel pouring of a reversible H-shaped steel universalbeam roughing mill set. The control program of the method comprises the following steps: setting the functional blocks FCYSDC01-FCYSDC15 as a determiner unit for abnormal manual steel pouring of thereversible H-shaped steel universal beam roughing mill set; and setting FCYSDC06, FCYSDC08, FCYSDC10 and FCYSDC16-FCYSDC22 as a manual speed control unit under the abnormal manual steel pouring stateof the H-shaped steel universal beam roughing mill set. When an abnormal manual steel pouring state occurs; the control program firstly decelerates and stops the three-frame main transmission of the universal beam roughing mill set. After setting the time of the three-frame shut-down, the setting value of the manual operation joy-stick output speed of the H-shaped universal beam roughing set is enabled (the setting value is shown in the description). During the period of time of abnormal manual steel pouring forced interruption, the roughing unit can have enough time to process the rolled pieces which normally stay in the universal roughing mill set, thereby thoroughly avoiding the violent self-excited oscillation of the three-frame main transmission of the universal beam roughing mill setcaused by sudden abnormal manual steel blocking slippage.

The invention discloses a switching power supply unit which includes a rectifying unit with a synchronous rectifying mode. The rectifying circuit is provided with a rectifying switch connected in series with a secondary coil of a main transformer and conducted synchronously with a conduction period of a main switch; and a commutation switch connected in parallel with the secondary coil and conducted synchronously with the conduction period of the main switch. The switching power supply unit is provided with an auxiliary switching circuit. The auxiliary switching circuit detects the generated self-oscillation when voltage flows across an output end and the main switch stops switching, and enables the commutation switch to be turned off to prevent continuous self-oscillation. The switching power supply unit can prevent continuous self-oscillation generated when the main switch is turned off.