First, the measurement principle of Doppler ultrasonic flowmeter
采用声学多普勒原理测量液体流量，即可测量多相流（污浊的液体，如市政污水、工业废水、原油、油水混合物、泥浆、矿浆、纸浆、果汁等），又可测量单相流（较纯净的液体，如自来水、江河原水、海水、化工液体等），应用范围较为广泛。 The Doppler ultrasonic flowmeter uses the acoustic Doppler principle to measure liquid flow, which can measure multiphase flow (fouling liquids, such as municipal sewage, industrial wastewater, crude oil, oil-water mixture, mud, pulp, pulp, juice, etc.), and It can measure single-phase flow (pure liquid, such as tap water, river water, seawater, chemical liquid, etc.), and has a wide range of applications.
When measuring multiphase flow, because the liquid contains reflective particles such as bubbles, solid particles, suspended matter, etc., the Doppler signal is a relatively narrow frequency band velocity. When it is a certain average value (sufficient straight pipe section can ensure its velocity More stable distribution), you can get higher measurement accuracy.
When measuring single-phase flow, the liquid contains fewer reflective particles. At this time, compared with the Doppler signal when measuring multi-phase flow, there is a big difference.
Generally, when a clean liquid flows through an elbow, tee, or half-open valve, the flow velocity distribution is turbulent and turbulent, which is called a turbulent state; when passing through a straight pipe section, the flow rate tends to stabilize. In this way, the interface is generated during the turbulent to stable flow. This interface is called the pressure interface or the shear wave interface. Near the elbow, tee, half-open valve, etc. (1 to 2 times the length of the inner diameter of the pipe), the speed of this interface is unstable. When leaving the elbow, tee, half-open valve, etc. (4 to 5 times the length of the inner diameter of the pipe), the interface flow rate is basically the same as the average flow velocity of the fluid. When leaving more than 10 times the length of the inner diameter of the pipe, this interface disappears and becomes a stable flow velocity distribution.
When measuring single-phase flow, the measurement point can be selected at a length of 4 to 5 times the inner diameter of the pipeline. At this time, the Doppler signal can be obtained at the pressure interface. However, this signal is weak and the frequency band is wide. It is necessary to make a special spectrum analysis circuit and amplifying operation circuit to ensure the measurement accuracy of the Doppler ultrasonic flowmeter when measuring single-phase flow.
2. Main application areas [(a) industry, (b) purpose]
(A) Sewage treatment plant
(B) Flow measurement at water inlet and outlet and intermediate links
(2) Crude oil
(B) Crude oil, oil-water mixture and oily sewage flow measurement.
(3) Sodium aluminate solution
(A) Aluminum plant
(B) Process flow measurement that cannot be measured by other flowmeters such as sodium aluminate solution
(4) Industrial water and drainage
(A) Steelmaking, ironmaking, chemical, pharmaceutical, papermaking and other plants
(B) Inspection of pump power, effective distribution management of flow in each process, and measurement of total discharge outlet
(5) Various pulp liquids
(A) Pulp and paper mill
(B) Flow management, proper replacement of pumps to reduce power costs.
(6) Coal / ore mixed water
(B) Flow measurement during coal preparation / dressing
(7) Sugar solution, starch solution
(A) Sugar factory, starch factory
(B) Processes applicable to edible pipes
(8) Water for cooling water and air-conditioning equipment, warm water
(A) Construction, building construction, maintenance of buildings
(B) Flow management and efficiency check
(9) Various processing fluids
(A) Chemical, pharmaceutical, and pharmaceutical factories
(B) Flow measurement at high / low temperature and high pressure
(10) Debris mixed water
(A) Construction company
(B) Flow measurement when sand, rocks, etc., which are the main seabed, are transported on a pump
(11) Rivers, sea water, salt water
(A) Chemical, food, pharmaceutical, petrochemical, salt factories
(B) Flow rate measurement mainly for cooling water and treated brine
(12) Clear water
(A) Electronic equipment manufacturing plant, chemical plant, semiconductor plant
(B) Measurement of fresh water flow
(13) Working oil
(A) Ironmaking, construction machinery, manufacturing plants
(B) Inspection and management of engine oil for switching on and off of large unloading trucks, and inspection and management of power lubricants for construction machinery.
(14) Cutting oil
(A) Automotive and related industry work machinery plants
(B) Flow rate distribution, inspection and management of working machine cutting oil.
In a mobile communication system, signals from a mobile station * moving relative to a base station are affected by the Doppler effect. The present invention proposes a technique for compensating a Doppler effect in a received signal according to a condition of a received signal channel. Therefore, Doppler frequency shift compensation can be performed only or mainly if the channel conditions are good enough.
The present invention belongs to the field of ultrasound technology, and is a method for measuring blood flow velocity with dual ultrasound beam Doppler. In this method, the two sets of transducers in the Doppler probe are respectively * ultrasonic beams, and the appropriate angle between the ultrasonic beam and the blood flow velocity is selected, so that the calculation formula of the blood flow velocity v and the deflection angle θ between the blood vessel and the skin is given . In the case of pulse Doppler, the transducer works in a time-sharing manner, and the corresponding calculation formulas for v and θ are given. The invention can be directly applied to a duplex ultrasound system. The invention can not only be applied to the continuous wave mode, but also can be applied to the pulse Doppler form, and the operation is simple, the accuracy is high, and the actual blood flow direction can be obtained.
Compensation of Doppler drift in mobile communication system
The invention relates to a method and a system for compensating the Doppler drift of a signal transmitted between a mobile station and a base station in a mobile communication system. In this method, the Doppler characteristics of two selected portions of the received signal are determined, and for each selected portion, the Doppler characteristics are in the form of a phase offset. Then, a larger phase offset is used as the Doppler characteristic to provide Doppler drift compensation for the received signal.
定向仪以及用多普勒定向仪定向的方法多普勒定向仪包括与定位点（53）有一定距离的至少一个天线（52）。 The Doppler ultrasonic flowmeter directional instrument and the method for directing with the Doppler directional instrument The Doppler directional instrument includes at least one antenna (52) at a certain distance from the positioning point (53). The at least one antenna (52) is mounted so that it can rotate around a rotation point (53) when in use. The at least one antenna (52) is designed to enable it to provide a first output signal including a Doppler frequency component that is received by the at least one antenna (52). There is a device (70) for providing a second output signal including a received signal that does not contain a Doppler shift component. A processing device (54-82) processes the first and second signals to obtain a Doppler frequency shift component. The determining means (88) determines a receiving direction from the received signal from the Doppler frequency shift component.
Compensation of Doppler frequency shift in a mobile communication system In a mobile communication system, signals from a mobile station * moving relative to a base station are affected by the Doppler effect. A technique for compensating for the Doppler effect is described, and estimated bit decisions are used for received bits that are very close to zero phase and are not damaged by the Doppler effect. The Doppler frequency shift measured using these estimated bits can then be provided to the signal bits away from the zero phase difference point.
System and method for narrowing the frequency uncertainty range of a Doppler shifted signalA method for making a Doppler shifted pilot signal in a * or other communication system (100) relative to a signal source and a receiver Systems and methods for narrowing the range of moving frequency uncertainties. * The communication system (100) includes a user terminal (124,126) (e.g., a mobile radiotelephone), a gateway (120,122,112) (a ground base station), and at least one * (116,118), whose locations and relative speeds are unknown. The method includes a step (309) of shifting a pilot signal within a plurality of assumed frequency ranges, a step (315) of coherently accumulating a sampling of a pilot signal within a plurality of chip ranges, and measuring an energy of the accumulated pilot signal samples Step (318), step (321) of accumulating energy measurements over multiple chip ranges to produce an energy accumulation value, and step (324) of determining which of a plurality of frequency assumptions results in the highest energy accumulation value.
Radar ice detector using parallel Doppler processing A radar ice detector using parallel Doppler processing can obtain more reliable and accurate radar ice detection technology. In one example, the present invention uses both coherent and non-coherent technologies to simultaneously obtain a high signal-to-noise ratio, a high signal-to-speckle standard deviation ratio, and a high signal-to-clutter echo ratio.
Doppler frequency shift estimation method based on statistics set in mobile communication system In mobile communication system, when the mobile station communicates in motion, the frequency of the signal received by the base station will change, which is called the Doppler effect. The object of the present invention is to provide a Doppler frequency shift estimation method applicable to various Doppler frequency shift distributions, a set of statistics for estimating Doppler frequency shift, and feedback cancellation based on mobile communication systems. The present invention proposes a set of statistics for estimating the Doppler frequency shift. It makes full use of the fixed information on the pilot channel of the base station in the third generation of mobile communications, obtains the basic statistics in the set of statistics, and uses simple calculations. The formulas can be used to obtain other statistics of each order in the statistics set, so that when Doppler frequency estimation is performed, the statistics of an appropriate order can be selected for estimation according to different distributions of the Doppler frequency shift and different parameters of the system. At the same time, the Doppler frequency shift estimation method based on feedback cancellation provided by the present invention uses the estimation to cancel the actual value, and then estimates the difference to obtain a new estimate to further cancel the actual value. This process is repeated continuously, so that It successively approximates the fixed Doppler frequency shift and adjusts the changing Doppler frequency in a mobile state. It has strong anti-interference ability and high accuracy. The Doppler frequency shift estimation method based on feedback cancellation proposed by this method is a feature of this method while part of the output signal can be directly used by the mobile communication system.
Estimation of Doppler frequency shift compensation in a mobile communication system describes a system and method for estimating Doppler frequency shift compensation in a mobile communication system. The channel impulse response determination circuit determines a channel impulse response of a channel receiving a signal. Using a set of known symbols and channel impulse responses, a reference vector is generated, and the error vector is then generated by comparing the reference vector with the received samples of the signal. In addition, the noise variance of the incoming signal can be determined. Subsequently, a Doppler correction factor having a real part representing the amplitude correction and an imaginary part representing the phase correction is estimated.
扩展估计系统一种接收设备多普勒扩展估计器包括接收机，用于通过因衰落而随时间变化的传输信道来接收信号，并将信号转换成数字抽样用于处理。 Doppler ultrasonic flowmeter extended estimation system A receiving device The Doppler extended estimator includes a receiver for receiving a signal through a transmission channel that changes with time due to fading, and converts the signal into digital samples for processing. A stabilizer operatively associated with the receiver stabilizes digital sampling. An estimator is operatively associated with the stabilizer for estimating the spectral density of the digital samples being stabilized. The correlator is operatively connected to the estimator for correlating the spectral density estimate with a function corresponding to an assumed correspondence of a plurality of Doppler spread values in order to select one of the Doppler spread values as an estimate of the actual Doppler spread.