Abstract: The present invention provides a wireless transmission system in which it is possible to exert a maximum path diversity effect even if the maximum number of effective branches is limited to a small number. A transmission timing control section (23) determines a transmission start timing to be a timing obtained by delaying a reference timing by a predetermined delay amount. A modulation section (21) modulates a signal by a modulation scheme such that an anti-multipath property is exerted when the signal is demodulated on a receiver side, and transmits the modulated signal at the transmission start timing. In a receiving station (12), a demodulation section (33) demodulates the receive signal to obtain receive data.

Abstract: A wireless transmission system capable of performing a multi-station simultaneous transmission of data, that is, simultaneously transmitting data by wireless to a plurality of stations. The wireless transmission system includes a plurality of wireless stations for transmitting/receiving data and it constitutes a system for path diversity by use of a wireless station at the transmitting end, a multipath transmission path, and a wireless station at the receiving end. At least one of the plurality of wireless stations decides, in accordance with a response packet responsive to a multi-station simultaneous transmission request packet transmitted by the wireless station or other stations, a plurality of delay amounts relative to a reference timing during the multi-station simultaneous transmission in the wireless transmission system.

Abstract: There is provided a new inter-station transmission method capable of extending, as compared with a conventional method, a time to be allocated for a transmission path delay of an inter-station transmission path within a predetermined turnaround time, and increasing an inter-station transmission distance as much as possible. A radio base station (20) reproduces a clock synchronized with a BSU transmission clock DCLK, the BSU transmission clock DCLK being used when transmitting downlink transmission data from a communication control station (10). Based on the reproduced clock, the radio base station (20) processes the downlink transmission data. Since this clock synchronization eliminates a necessity of data format conversion between the communication control station (10) and the radio base station (20), a buffer such as a FIFO for accumulating transmission data in preparation for the conversion is no longer necessary. Consequently, a delay time caused by the buffer in a conventional process is eliminated.

Abstract: A diversity receiver carries out error detection, error correction, and data detection on each detected data string 21. An output switching unit 17 outputs a decoded data string 24 of a branch selected by a branch selector 16. The branch selector 16 selects a branch of highest priority in priority information 29 from branches of which a data detection signal 25 indicates that the data is valid and of which the number of error symbols 22 coincides with a minimum value. In the priority information 29, higher priority is assigned to a branch that includes an antenna of which the coverage is closer to that of an antenna included in a branch selected at the immediately-previous time. Thus, selected from the plurality of branches having the minimum number of error symbols 22 is the one that includes the antenna of which the coverage is closest to the coverage of the antenna included in the branch selected at the immediately-previous time.

Abstract: A diversity receiver carries out error detection, error correction, and data detection on each detected data string 21. An output switching unit 17 outputs a decoded data string 24 of a branch selected by a branch selector 16. The branch selector 16 selects a branch of highest priority in priority information 29 from branches of which a data detection signal 25 indicates that the data is valid and of which the number of error symbols 22 coincides with a minimum value. In the priority information 29, higher priority is assigned to a branch that includes an antenna of which the coverage is closer to that of an antenna included in a branch selected at the immediately-previous time. Thus, selected from the plurality of branches having the minimum number of error symbols 22 is the one that includes the antenna of which the coverage is closest to the coverage of the antenna included in the branch selected at the immediately-previous time.

Abstract: In the transmitter which carries out burst transmission using information data as a packet, if the status is divided into four modes, namely, burst stop mode, burst rising mode, burst continuous mode, and burst falling mode, a waveform shaping equipment designed to read out shaped waveform data for each mode from outputs of either of the two memory tables, the first memory table which holds waveform data for specific data patterns used in common in burst rising mode and burst falling mode and the second memory table which holds waveform data for all data patterns used in the burst continuous mode, or a waveform shaping equipment comprising the third memory table which holds waveform data corresponding to all the data patterns used in the burst rising mode and the fourth memory table which holds waveform data corresponding to all data patterns used in the burst falling mode and generating shaped waveform data by synthesizing the two outputs of the third and the fourth memory tables at the time of burst continu

Abstract: A demodulator 1 obtains demodulated data in a plurality of channels. Estimating portions 2a and 2b estimate and output the numbers of erroneous symbols and error locations thereof in the demodulated data. A data comparator 3 compares the demodulated data corresponding to the error locations with the demodulated data in the corresponding locations in other channels to determine whether the error location is correct, and it outputs a decision signal in response to the determination. A data selector 4 selects one of the demodulated data in the plurality of channels on the basis of the numbers of erroneous symbols and the decision signals and outputs the data as selected data. It is then possible to maintain the reliability of error detection even when a less redundant short error detecting code is used, and also to accurately select a channel of good quality even when the demodulated data in all channels contain the same extent of errors.

Abstract: In the transmitter which carries out burst transmission using information data as a packet, if the status is divided into four modes, namely, burst stop mode, burst rising mode, burst continuous mode, and burst falling mode, a waveform shaping equipment designed to read out shaped waveform data for each mode from outputs of either of the two memory tables, the first memory table which holds waveform data for specific data patterns used in common in burst rising mode and burst falling mode and the second memory table which holds waveform data for all data patterns used in the burst continuous mode, or a waveform shaping equipment comprising the third memory table which holds waveform data corresponding to all the data patterns used in the burst rising mode and the fourth memory table which holds waveform data corresponding to all data patterns used in the burst falling mode and generating shaped waveform data by synthesizing the two outputs of the third and the fourth memory tables at the time of burst continu

Abstract: A differential detecting apparatus includes samplers 1 and 2, differential detection calculating unit 3, and two post-detection filters 4 and 5. Differential detection calculating unit 3 performs a differential detection with time-division multiplexing on data output from these samplers and alternately outputs a data sequence of a part of cosine component of the phase difference of the modulated signal and a data sequence of the rest of the cosine component. Differential detection calculating unit 3 also alternately outputs a data sequence of a part of sine component of the phase difference and a data sequence of the rest of the sine component. Each of post-detection filters 4 and 5 includes linear interpolating filter 35 and integral filter 36 which are connected in series. The linear interpolating filter 35 obtains a moving average from successive three pieces of input data weighted by 1:2:1 and the integral filter 36 obtains an integral value from successive k pieces of input data.

Abstract: In the transmitter which carries out burst transmission using information data as a packet, if the status is divided into four modes, namely, burst stop mode, burst rising mode, burst continuous mode, and burst falling mode, a waveform shaping equipment designed to read out shaped waveform data for each mode from outputs of either of the two memory tables, the first memory table which holds waveform data for specific data patterns used in common in burst rising mode and burst falling mode and the second memory table which holds waveform data for all data patterns used in the burst continuous mode, or a waveform shaping equipment comprising the third memory table which holds waveform data corresponding to all the data patterns used in the burst rising mode and the fourth memory table which holds waveform data corresponding to all data patterns used in the burst falling mode and generating shaped waveform data by synthesizing the two outputs of the third and the fourth memory tables at the time of burst continu

Abstract: A level detector 2 detects variation of the amplitude of an input signal a to output a level signal b representing HIGH or LOW in order to define the head portion of the input circuit a. A time constant control signal 3 generates a time constant control signal c based on the level signal b to control a time constant of an estimator 4 so as to make the time constant small for a prescribed period from a time when the level signal b varies from HIGH to LOW. The estimator 4 estimates DC offset included in the input signal a with the a time constant variation according to the time constant control signal c to output an estimate d. A compensator 1 subtracts the estimate d from the input signal a to obtain a compensation output. Therefore, in the estimator 4, the speed of estimating the DC offset is different between a period corresponding to the head portion of the input signal a and other periods.

Abstract: An antenna switched diversity receiver comprising a plurality of physically separated antennas, a switching unit for selectively switching to one of the plurality of antennas to receive a burst in a time series, a decoding unit for decoding transmission data contained in the received burst in a reversed manner to coding, a bit-error-detecting unit for detecting a bit error in decoded data in each received burst, and a control unit for controlling the switching unit in accordance with the bit-error detection result. The receiver may additionally include a RSSI (received signal strength indicator) checking unit for checking a RSSI of a switched antenna and a RSSI holding unit for holding a RSSI. The receiver constructed as above controls switching based on detection of at least one bit error in each of m consecutive bursts burst alone or together with the RSSI. As a result, the receiver obtains excellent diversity effect while being compact and economical.

Abstract: A data transmitting and receiving apparatus is disclosed. The receiving apparatus receives a spread spectrum signal prepared by modulating a carrier wave with data to produce a data modulated signal and multiplying the data modulated signal with a spreading signal which has a bandwidth greater than that of the data modulated signal. The receiving apparatus may include three bandpass filters for passing three different band portions of a full band of the spread spectrum signal and producing an intermediate signal, and a detector for detecting data from the intermediate signal and for producing a detector output. The apparatus may also include a reception state evaluation device for detecting the current reception state of the detector and for producing a poor reception signal, when the detector is in a poor reception state. The poor reception signal is used for changing from a current band to another band.

Abstract: An auto player technique is provided in a recording/reproducing apparatus storing a plurality of disks, wherein size of the apparatus can be reduced in height and width and positioning accuracy can be increased. A pair of tray stockers are disposed right and left. A lifter transporting the tray in a vertical direction is disposed behind the tray stockers. The lifter includes a tray extracting mechanism selectively extracting disks from the tray stockers. The tray extracting mechanism simultaneously engages with two trays disposed at the same height of the right and left tray stockers when extracting trays. A recording/reproducing device is disposed below the lifter. A drive mechanism engages with the recording/reproducing device to shift it in a right and left direction. A lock mechanism is provided to engage with the recording/reproducing device when the drive mechanism is disengaged from the recording/reproducing device.

Abstract: A digital signal transmission device for transmitting a signal generated by modulating a carrier wave according to a binary or M-ary data sequence. Such device comprises a differentially encoding unit for converting the original data sequence into a transmission data sequence, a waveform generation unit for.degree. generating a phase transition waveform in each time slot which corresponds to each data included in the transmission data sequence, and a modulation unit for modulating the carrier wave according to a signal which has the phase transition waveform generated by the waveform generation unit. The information to be transmitted is present in a difference between two data which are spaced form each other by a prescribed time slots.

Abstract: A transceiver for transmitting and receiving a signal having the same frequency according to a time-division includes a local oscillator for generating a local signal having a first frequency, a frequency converter for converting the local signal into a carrier signal, a modulator for modulating the carrier signal by using a transmitting baseband signal so as to generate a transmitting signal having a second frequency and a receiving section for receiving a receiving signal having the second frequency which is the same as that of the transmitting signal. The frequency convertor includes a fractional frequency convertor for converting a signal having an input frequency into a signal having an output frequency. Wherein, the output frequency is n.sub.2 /n.sub.1 times the input frequency, where n.sub.1 is an integer greater than 2, n.sub.2 is an integer greater than 1, n.sub.1 and n.sub.

Abstract: A disk magazine for use with an audio and a video instrument of the type using disks and accommodating a stack of disks therein includes generally rectangular trays each of which is bodily removable from a casing of the magazine through an opening, which is formed only through the front end of the casing. Each tray is guided by horizontally aligned ones of tray guides which are arranged in steps on the inner periphery of each of opposite side walls of the casing with respect to an intended direction of tray insertion. Whether or not the tray is inserted in a correct position into the casing is checked to prevent the tray from being loaded in a position other than the correct one.