Abstract:
A transmit phase control system of synchronization burst is disclosed for use in a SDMA/TDMA satellite communication system in which a phase error between a synchronization burst transmitted from an earth station and a synchronization window, assigned as a time slot on a satellite for returning the synchronization burst, is measured and the transmit phase of the synchronization burst is controlled based on the measured value. Phase error measurement is achieved a plurality of times in connection with the received synchronization burst of each station, and a decided phase error is derived based on the measured value obtained by the plurality of measurements. The transmit phase of the synchronization burst is then controlled in accordance with the decided phase error. Further, the phase error decision is achieved at every 1/n (n being an integer larger than 1) round trip and the present synchronization burst is transmitted with its transmit phase corrected corresponding to a value that is the sum of the phase corrected value of the n preceding phase correction instants subtracted from the decided phase error at the present instant.
Abstract:
In the receiving terminal of a PCM (Pulse Code Modulation)-TDMA (Time Division Multiple Access) system, a data is demodulated from a received burst signal, said data is written in a buffer register by using a burst clock which is regenerated from the received burst signal. The content of said buffer register is read by using a local clock which is generated in the receiving office and, after the data is read out, said data is controlled by said local clock.
Abstract:
In a dust collection device attached to a hammer drill, a filter is provided in a dust box at a position at which the filter covers an outlet provided on a rear face of a lid body, in a state such that a filter surface projects into the dust box from the rear face of the lid body. A space is formed between an inner face of a box main body and a side face of the filter that is adjacent to the filter surface. Air outlets are provided to guide air, which flows in through an inlet, toward the space.
Abstract:
In a dust collection device attached to a hammer drill, a filter is provided in a dust box at a position at which the filter covers an outlet provided on a rear face of a lid body, in a state such that a filter surface projects into the dust box from the rear face of the lid body. A space is formed between an inner face of a box main body and a side face of the filter that is adjacent to the filter surface. Air outlets are provided to guide air, which flows in through an inlet, toward the space.