149 results about "Frequency dependence" patented technology

Many reservoirs of interest include heavy oil. In such reservoirs, parti at normal temperatures, many instruments commonly used for formation evaluation may not be able to distinguish between heavy oil and bound water in the formation. Passive or active heating is used to elevate the temperature of the fluids in the formation. At elevated temperatures, distinguishing between heavy oil and bound water is easier. Of particular interest is the increase in the resolvability of the transverse relaxation time T2 of NMR spin echo measurements. Additionally, the dielectric constant and the loss tangents of water and heavy oil show different temperature and frequency dependence.

The variable gain amplifier includes a bias circuit (BC) 1, a matching circuit (MC) 2, a variable gain resistive feedback amplifier (FA) 3 and an output follower (EA) 4. The resistance values of the load resistance Rc and feedback resistance Rf are changed in cooperation. In a case of making the load resistance Rc a high resistance to set the low noise amplifier to a high gain, the feedback resistance Rf is also made a high resistance, the feedback time constant τfb(c1)≈2π·RfCbe / (1+gmRc) of the closed loop of the resistive negative feedback amplifier 3 becomes substantially constant, and then the amplifier has a gain small in frequency dependency over a wide bandwidth. In a case of making the load resistance Rc a low resistance to set the low noise amplifier to a low gain, the feedback resistance Rf is also made a low resistance. The feedback resistance Rf with the low resistance increases the negative feedback quantity, and thus the amplifier is set to a low gain. Also, the load resistance Rc is made a low resistance, and the feedback time constant τfb(c1) becomes substantially constant. The gain is not lowered further in a high frequency region.

An adaptive equalizer comprises an adjustable equalizer circuit (10) that allows to enhance the frequency dependence of contents of the transmitted signals which suffer from losses in the connected transmission channel. A blind equalization tuning procedure is proposed that operates without knowledge about the characteristic of transmission channel. Phase positions of transitions in the equalized signal are detected through a transition phase detector (44). A digital post-processing circuit evaluates a measure for spread of the detected phase positions of transitions, accumulated over a plurality of the symbol periods. The digital post-processing circuit (14) controls the adjustable equalizer, setting the adjustable equalizer to a setting wherein the detected spread is minimized.

An adaptive equalizer comprises an adjustable equalizer circuit that allows to enhance the frequency dependence of contents of the transmitted signals which suffer from losses in the connected transmission channel. A blind equalization tuning procedure is proposed that operates without knowledge about the characteristic of transmission channel. Phase positions of transitions in the equalized signal are detected. A digital post-processing circuit evaluates a measure for spread of the detected phase positions of transitions, accumulated over a plurality of the symbol periods. The digital post-processing circuit controls the adjustable equalizer, setting the adjustable equalizer to a setting wherein the detected spread is minimized.

A condenser microphone unit that has a capacitor element with a large effective area and a high signal-noise ratio but does not have frequency-dependence occurring with sound waves beyond the audio frequency range. A solid cylindrical fixed electrode pole is used as a fixed electrode. A diaphragm includes a rectangular synthetic resin film having a length smaller than or equal to the axis length of the fixed electrode pole, and a width equal to a circumferential length of the fixed electrode pole, the synthetic resin film including an electrode film on one face and ribs on the other face and entirely partitioned by the ribs into a plurality of diaphragm regions. The synthetic resin film is attached to an entire outer periphery of the fixed electrode pole such that the ribs are in contact with the outer periphery.

A frequency domain transforming section transforms mixed signals observed by multiple sensors into mixed signals in the frequency domain, a complex vector generating section generates a complex vector by using the frequency-domain mixed signals, a normalizing section generates a normalized vector excluding frequency dependence of the complex vector, and a clustering section clusters the normalized vectors to generate clusters. Then, a separated signal generating section generates separated signals in the frequency domain by using information about the clusters and a time domain transforming section transforms the separated signals in the frequency domain into separated signals in the time domain.

Weather radar for measuring radar signals in the GHz range with a receiver containing at least one signal path, the receiver comprising a receiving facility for an incoming radar signal, on which a test signal generated by a test signal generator is superimposed in a coupler, and a processing device to amplify, filter and convert both signals to lower frequencies, wherein for filtering a matched filter is provided, and with an evaluation device in which calibration parameters of the signal path are derived from the test signal for the frequency of the test signal in order to determine the signal strength of the received radar signal, wherein the test signal is superimposed with at least one frequency differing from the frequency of the radar signal, so that the radar signal and the test signal are processed separately from one another by the evaluation device, and the calibration parameters of the signal path for the frequency of the radar signal are determinable from the test signal through a modeling of the frequency dependence of the calibration parameters for frequencies around those of the radar signal.

An apparatus and method for measuring a flow velocity profile of fluid traveling in a pipe or conduit uses an ultrasonic wave transmitted from an ultrasonic wave transducer mounted at an angle on the outside of a pipe using a wedge, and made incident onto the fluid in the pipe to measure the fluid flow velocity profile, using the principle that a frequency of an ultrasonic wave, reflected by a reflector existing in the fluid, is changed depending on a flow velocity due to Doppler effect. The transmission frequency and the angle of incidence onto the pipe can be selected to suppress frequency dependence of a measured value due to Lamb wave and allow the flow velocity or flow rate of fluid to be measured with a greater accuracy.