44results about How to "Applicable frequency range is wide" patented technology

The invention discloses a self temperature compensation circular waveguide resonant cavity, which relates to a waveguide resonant cavity and can remarkably reduce the influence of temperature on the resonant frequency of the resonant cavity. In the resonant cavity, a short-circuit cylinder (2) consists of a circular bottom surface (5) and a columnar cylinder wall (6), the bottom surface (5) of the short-circuit cylinder (2) is connected with one bottom surface cavity wall (7) of a metal cavity (1) through a support body (3), the thermal expansion coefficient of the support body (3) is greater than that of the metal cavity (1), and the outside diameter of the short-circuit cylinder (2) is slightly smaller than the inside diameter of a side wall (8) of the metal cavity (1); the bottom surface (5) of the short-circuit cylinder (2), the other bottom surface cavity wall (9) of the metal cavity (1) and the side wall (8) of the metal cavity form a resonant space (10) of electromagnetic wave; and an input/output coupling device (4) is positioned on the side wall (8) or the bottom surface cavity wall (9) of the metal cavity (1) in the resonant space (10).

The present invention provides a composite sound absorption plastic preparation method, which comprises: uniformly stirring and mixing 30-70% by mass of a polyvinyl chloride resin, 10-20% by mass of rock wool, 20-60% by mass of a nitrile butadiene rubber, 10-20% by mass of hollow glass micro-beads, 0.1-5% by mass of a silane coupling agent, 0.5-3% by mass of magnesium hydroxide, and 1-5% by mass of a magnesium stearate stabilizer, carrying out mixing on the obtained mixture for 10-30 min on a mixer at a temperature of 130-150 DEG C to prepare a green body, and forming the green body in an oven at a temperature of 200-220 DEG C to prepare the sound absorption material with excellent comprehensive performances. According to the present invention, the hollow glass micro-bead component is added based on the polyvinyl chloride, the rock wool and the nitrile butadiene rubber, such that a sound and noise absorption range is wide, and a sound absorption coefficient is high; with high porosity of the material and three-dimensional uniform distribution of pores, excellent acoustic performances are provided, wherein a sound absorption coefficient is high, and an application frequency band range is wide; and characteristics of easy processing, no pollution, dust-resistance, moisture resistance, good decoration effect and the like are provided.

The invention discloses a Gysel-type power divider based on a substrate integrated waveguide, and the power divider comprises a first port, a second port, a third port, a fourth port, and a fifth port. The first port is disposed on a central line of the power divider, and the power divider is symmetric relative to the central line. The first port is a common port, and the second and third ports are branch ports. The fourth and fifth ports are load ports. The power divider employs a substrate integrated waveguide structure, and comprises an upper metal surface, a central dielectric plate, and a lower metal surface. Two rows of second metal post line columns are disposed between the upper metal surface and the lower metal surface. Each row of second metal post line columns comprises a plurality of metal columns, and each metal column contacts with the upper metal surface and the lower metal surface. The power divider meets the actual demands of high power and high isolation, is small in size, is light in weight, and is suitable for the power combination and distribution of various types of SIW systems.

The invention discloses an ultrasonic power supply and a power supply method thereof. The ultrasonic power supply comprises a main control unit, a first modulator, a power amplifier and a coupler, the main control unit is used for generating a preset signal; the first modulator is used for performing pulse width modulation on the preset signal to obtain an electric pulse; the power amplifier is used for amplifying the electric pulse and outputting the amplified electric pulse to the coupler; the output end of the coupler is used for being connected with an ultrasonic component. According to the present invention, the technical problem that the working stability of an existing ultrasonic power supply is worse due to the fact that the output power linearity of the existing ultrasonic power supply is poor, is solved.

The invention discloses a broadband high-precision phase-locked loop circuit which comprises a phase-looked loop 1, a phase-looked loop 2 and a loop selection module. The phase-looked loop 1 is high in loop gain and wide in frequency range and is used for rough locking of frequency points. The phase-looked loop 2 is narrow in loop bandwidth and used for reducing frequency and phase errors and guaranteeing low jitter. The loop selection module realizes operation switching of the phase-looked loop 1 and the phase-looked loop 2 according to digital signals outputted by a digital filter in the phase-looked loop 1. The broadband high-precision phase-locked loop circuit is characterized in that in initial operation, the phase-looked loop 1 high in loop gain is adopted for rough locking of a target frequency point, then the loop selection module controls to switch operation of the phase-looked loop 2, and accurate frequency and phase adjustment is realized. The broadband high-precision phase-locked loop circuit has advantages of wide frequency locking range, quickness in capturing, high precision, high stability and the like.

The invention discloses a phase locked loop circuit based on a spin oscillator. The phase locked loop circuit comprises a phase detector, a lowpass filter and the spin oscillator. When a control signal is applied to the spin oscillator, an oscillation signal is generated. The oscillation signal is output through the output end of the phase locked loop circuit and is fed back to the phase detector through a feedback loop which is connected with the output end of the phase locked loop circuit and the phase detector. The spin oscillator may comprise a spin injection layer and a magnetic precession layer arranged on the spin injection layer. When the spin injection layer receives non-spin polarized current input, spin polarized current output is generated. The magnetic precession layer is formed by a magnetic conductive material and receives a spin polarized current from the spin injection layer. In response to the spin polarized current, a magnetic torque of the magnetic precession layer generates precession, thereby generating the oscillation signal.

The invention discloses a nickel-zinc ferrite material and a preparation method thereof. The nickel-zinc ferrite material comprises main components and auxiliary components, wherein the main components consist of the following components in percentage by mole: 48%-51% of Fe oxide, 12%-18% of Ni oxide, 15%-23% of Zn oxide and 4%-7% of Co oxide, with the balance being Cu oxide; and the auxiliary components comprise a Mn compound and a Ca compound. The nickel-zinc ferrite provided by the invention has the characteristics of wide applicable frequency range, high magnetic conductivity peak frequency, small specific loss coefficient, high saturation magnetization, low coercive force and high Curie temperature, and presents wide application prospects.

The invention relates to the technical field of vibration harmonic control, in particular to an electromagnetic vibration table harmonic control system and method based on a neural network inverse model, and the system comprises a program control signal source, the neural network inverse model, an electromagnetic vibration table system, a vibration detection unit, a data collection unit, data processing software and harmonic analysis software. The system is based on a neural network inverse model, an electromagnetic vibration table is excited by setting an input quantity, an input voltage signal and an output vibration signal are processed to obtain a neural network inverse system training sample, and the output of the trained neural network inverse model is connected with the input of the electromagnetic vibration table in series. Accurate tracking of vibration signals output by the electromagnetic vibration table on expected signals input into the neural network inverse model is achieved. The control system disclosed by the invention is simple in composition structure, simple and convenient in operation process and wide in applicable frequency range, and has relatively high control precision on harmonic waves of vibration signals output by the electromagnetic vibration table.

The invention provides a method and device for calculating a true RMS; the method comprises the steps: setting an analog-to-digital converter to be in an automatic continuous conversion mode, and setting a corresponding conversion frequency; according to the Nyquist sampling theorem, carrying out high-speed sampling on the measured signal and the internal signal through an analog-to-digital converter, and obtaining an external alternating current signal and an internal voltage signal; calculating an AC signal value according to the external AC signal and the internal voltage signal; and carrying out integral calculation according to the alternating current signal value by combining a thermal equivalence principle to obtain a voltage true RMS. A low-cost scheme can be adopted, the true RMS is calculated according to an integral method, the stability is good, and the precision is high.