Abstract: This invention improves the frequency acquisition range and the resistance to multipath interference. In a digital signal transmission system using OFDM, on the transmission side, some or all of a plurality of equidistant carrier positions are treated as reference carrier positions. The actual transmitted carriers are arranged in a predetermined pattern non-equidistant to the frequency carrier positions to form an OFDM symbol. This OFDM symbol is periodically transmitted as frequency reference symbols. On the reception side, the carrier arrangement pattern of the frequency reference symbols is detected, a carrier frequency offset is detected from the detected pattern offset, and the carrier frequency is compensated based on the frequency offset.

Abstract: A process for the polymerization of olefinic hydrocarbons is carried out in the presence of a catalyst comprising a catalyst component derived from reacting a compound of the formula Me.sup.1 R.sup.1.sub.n X.sup.1.sub.4-n, a compound of the formula Me.sup.2 R.sup.2.sub.m X.sup.2.sub.z-m, an organocyclic compound having two or more conjugated double bonds and a carrier of inorganic or polymeric material, and a modified organoaluminum compound having Al--O--Al bonds, the resulting polyolefins having a relatively wide molecular weight distribution, a relatively narrow composition distribution and increased bulk density.

Abstract: A catalyst component is disclosed for use in the homo- or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula Me.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q and a second compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified organoaluminum compound to form a catalyst composition capable of providing high molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: A hierarchical quadrature frequency multiplex signal transmission apparatus that produces a plurality of modulated signals in which multiple layers of hierarchical information data are associated with a plurality of hierarchically graded modulation forms. The apparatus also interleaves symbols within a frame of the hierarchical information data in both a time axis and a frequency axis. In addition, the apparatus may differentially encode one of the hierarchically graded modulation forms. Further, the apparatus performs an inverse Fourier transform on the symbols, by associating each of the plurality of hierarchically graded modulation forms with a corresponding predetermined carrier. Also disclosed is an apparatus for receiving the hierarchical quadrature frequency multiplex signal and the format of the hierarchical quadrature frequency multiplex signal.

Abstract: A catalyst component is disclosed for use in the homo- or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula Me.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q and a second compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified or organoaluminum compound to form a catalyst composition capable of providing high molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: A process for the polymerization of olefinic hydrocarbons is carried out in the presence of a catalyst comprising a catalyst component derived from reacting a compound of the formula Me.sup.1 R.sup.1.sub.n X.sup.1.sub.4-n, a compound of the formula Me.sup.2 R.sup.2.sub.m X.sup.2.sub.z-m, an organocyclic compound having two or more conjugated double bonds and a carrier of inorganic or polymeric material, and a modified organoaluminum compound having Al--O--Al bonds, the resulting polyolefins having a relatively wide molecular weight distribution, a relatively narrow composition distribution and increased bulk density.

Abstract: An OFDM synchronization demodulation circuit includes a receiving circuit for receiving an orthogonal frequency division multiplexing (OFDM) modulation signal. An orthogonal detection circuit orthogonally detects the OFDM modulation signal from the receiving circuit using a detected carrier. A demodulation circuit orthogonally demodulates the detected OFDM multiplex modulation signal from the orthogonal detection circuit by sampling the OFDM multiplex detection signal using a detected clock. A constellation analyzing circuit analyzes the constellation of demodulated symbols of predetermined carriers in the demodulated OFDM multiplex signal signal. A carrier frequency deviation detection circuit detects a frequency deviation of the detected carrier based on a rotation of the constellation of the demodulated symbol detected by the constellation analyzing circuit.

Abstract: An OFDM synchronization demodulation circuit includes a recovery circuit, an orthogonal axis demodulation circuit, a first and second delay circuit, a correlation calculation circuit, a guard timing detection circuit, and an OFDM signal demodulation circuit. The receiving circuit receives an orthogonal modulated wave based on an orthogonal frequency division multiplex (OFDM) modulated signal having an available symbol period and a guard period, where the guard period of the orthogonal modulated wave is based on a part of the available symbol period. The orthogonal axes demodulation circuit demodulates an in-phase axis detection signal and an orthogonal axis detection signal for the OFDM modulated wave from the receiving circuit using orthogonal detection. The first delay circuit delays the in-phase axis detection signal by the available symbol period, and the second delay circuit delays the orthogonal axis detection signal by the available symbol period.

Abstract: A catalyst component is disclosed for use in the homo-or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula Me.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q, a second compound of the formula Me.sup.2 (OR.sup.3).sub.m R.sup.4.sub.n X.sup.2.sub.z-m-n and a third compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified organoaluminum compound to form a catalyst composition capable of providing controlled molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: A disk player has a guide member for guiding an optical pickup carrier along both sides of a double-sided disk. In order to prevent interference between the pickup carrier and the periphery of the disk during turning movement of the pickup carrier around the periphery of the disk from one of the upper and lower sides of the disk to the other side, the guide member is shaped like a horseshoe. The guide member includes upper and lower straight sections for guiding the pickup carrier, respectively, along the upper and lower sides of the disc, and an arched section extending vertically around the periphery of the disk and connecting the outer ends of the upper and lower straight sections. The upper and lower straight sections are not parallel to each other, but rather they are inclined in such a fanlike manner that the outer ends are wider apart.

Abstract: A catalyst component is disclosed for use in the homo- or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula Me.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q, a second compound of the formula Me.sup.2 (OR.sup.3).sub.m R.sup.4.sub.n X.sup.2.sub.z-m-n and a third compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified organoaluminum compound to form a catalyst composition capable of providing controlled molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: A catalyst component is disclosed for use in the homo-or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula Me.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q and a second compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified organoaluminum compound to form a catalyst composition capable of providing high molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: A process for the polymerization of olefinic hydrocarbons is carried out in the presence of a catalyst comprising a catalyst component derived from reacting a compound of the formula Me.sup.1 R.sup.1.sub.n X.sup.1.sub.4-n, a compound of the formula Me.sup.2 R.sup.2.sub.m X.sup.2.sub.z-m, an organocyclic compound having two or more conjugated double bonds and a carrier of inorganic or polymeric material, and a modified organoaluminum compound having Al--O--Al bonds, the resulting polyolefins having a relatively wide molecular weight distribution, a relatively narrow composition distribution and increased bulk density.