Abstract: A digital phase-locked loop (DPLL) circuit, which achieves a high-precise phase matching between input and output clocks at high speed, irrespective of phase difference between both, is disclosed.

Abstract: A frequency-offset removal apparatus comprises a receiving section for receiving a signal including a training sequence, a local oscillator for generating an oscillating signal to synchronize with the received signal, a frequency sweeping section for sweeping the frequency of the oscillating signal through a specific frequency which is identical with the carrier frequency of the received signal, a frequency shifting section for shifting the carrier frequency of the received signal by each oscillating signal, a selector for selecting one specific frequency-shifted-signal having the nearest frequency to the specific frequency from the frequency-shifted-signals generated in the frequency shifting section, and a frequency adjusting circuit for adjusting the frequency of the oscillating signal to generate a specific oscillating signal which produces the specific frequency-shifted-signal after shifting by the received signal.

Abstract: A demodulation apparatus incorporating an adaptive equalizer, capable of realizing a highly reliable communication, lower power consumption, and a compact size. In the demodulation apparatus, an output of one of two demodulators, at least one of which including an equalizer, is selected according to a presence or absence of multipath which is determined from a non-coincidence of bit codes, eye apertures, bit error ratea, or a matched filter output, while the operation of the other demodulator is stopped for reduction of power consumption, by stopping a supply of power or clock signals to the other demodulator. In a case using a frequency offset detection unit and a frequency offset memory, one of these is selected according to a convergence or divergence of an error signal from an equalizer, while the operation of the other one is stopped for reduction of power consumption.

Abstract: A demodulation apparatus incorporating an adaptive equalizer, capable of realizing a highly reliable communication, lower power consumption, and a compact size. In the demodulation apparatus, an output of one of two demodulators, at least one of which including an equalizer, is selected according to a presence or absence of multipath which is determined from a non-coincidence of bit codes, eye apertures, bit error rates, or a matched filter output, while the operation of the other demodulator is stopped for reduction of power consumption, by stopping a supply of power or clock signals to the other demodulator. In a case using a frequency offset detection unit and a frequency offset memory, one of these is selected according to a convergence or divergence of an error signal from an equalizer, while the operation of the other one is stopped for reduction of power consumption.

Abstract: Diversity receiver having many diversity branches comprises adaptive equalization sections for equalizing the training signal sampled on the basis of adjustable tap coefficients, and adjusting the tap coefficient every code element in the training signal so as to minimize the intensity of an error signal defined by the difference between the equalized training signal and the already-known training signal, error signal intensity detecting sections for detecting the intensity of the error signal every code element, a switching section for switching to a diversity branch having the minimum signal intensity of error signals in the respective diversity branches.

Abstract: A demodulation apparatus incorporating an adaptive equalizer, capable of realizing a highly reliable communication, lower power consumption, and a compact size. In the demodulation apparatus, an output of one of two demodulators, at least one of which including an equalizer, is selected according to a presence or absence of multipath which is determined from a non-coincidence of bit codes, eye apertures, bit error rates, or a matched filter output, while the operation of the other demodulator is stopped for reduction of power consumption, by stopping a supply of power or clock signals to the other demodulator. In a case using a frequency offset detection unit and a frequency offset memory, one of these is selected according to a convergence or divergence of an error signal from an equalizer, while the operation of the other one is stopped for reduction of power consumption.

Abstract: A method of an apparatus for decision feedback equalization, capable of dealing with time reversal for the transmission characteristic arising in a course of equalization. Without a considerable increase of the number of taps used and the resulting reduction of the response speed. In this apparatus, a number of feedforward taps for providing a forward part and a number of feedback taps for providing a feedback part are controlled according to whether the transmission signal is to be read in a normal time direction or in a reversed time direction; the forward part and the feedback part are added; and the digital transmission signal is reconstructed according to a result of the addition.

Abstract: A process for firing ceramic shaped bodies is disclosed, which comprises the step of making a heating temperature in a temperature range up to a decomposing temperature of a shaping aid contained in the ceramic shaped body smaller than that in a temperature range from the decomposing temperature to a firing temperature. A tunnel kiln is also disclosed, which comprises a preheating zone, a firing zone, a waste heat zone, combustion burners provided at the firing zone, an exhaust means provided at an inlet side of the preheating zone for evacuating combustion gases from the combustion burners outside the kiln, and another exhaust means provided at an outlet side of the preheating zone for evacuating the combustion gases outside the kiln.

Abstract: In a modulator for converting two digital signals of I channel and Q channel in base band into analog signals and for converting a component of the signals whose phase is the same as a carrier and another component of the signals whose phase is orthogonal to the carrier so as to produce an orthogonally modulated wave, the two digital signals are connected to one signal train by time-sharing and multiplexing them and the converted analog signals are separated to two analog signals for the I channel and the Q channel and thereby a digital modulator can be structured by using only one digital/analog converter resulting in reducing the adjustment points and the production cost.

Abstract: A tunnel kiln for firing molded ceramic green products includes a gate for feeding a kiln car into and out of the kiln. The gate located at low temperature parts of the kiln includes side walls made of a stainless steel having inclined surfaces and a ceiling made of a stainless steel and having inclined surfaces toward the side walls. The tunnel kiln further includes sand seals at connections between the side walls and the ceiling and receiving bases provided under lower ends of the side walls for receiving pyrolytically decomposed products. The side walls are formed with exhaust ports communicating with the receiving bases so that the pyrolytically decomposed products flow along the inclined surfaces of the ceiling and the side walls are once collected in the receiving bases and exhausted through the exhaust ports of the side walls to the outside of the kiln. With this arrangement, defective ceramic products due to decomposed products attached thereto are completely eliminated.

Abstract: A particulate lead titanate ceramic obtained by calcining a mixture containing TiO.sub.2 and PbO at 1150.degree.-1300.degree. C., the proportion of the PbO being greater than 1 mole per mole of the TiO.sub.2. A composite material having the particulate lead titanate ceramic supported in an organic substrate exhibits improved piezoelectric properties and is useful as a piezoelectric element or pyroelectric element.

Abstract: An underwater acoustic wave transmitting and receiving unit having excellent characteristics for both transmitting and receiving and providing stable characteristics over long operating periods. A plate-shaped polarized piezoelectric resonator is provided formed of at least one plate made of a complex of fluorosilicon rubber and lead titanate. The resonator is sealed in a rubber casing filled with an insulating liquid matching the water around the casing in acoustic impedance.