摘要:
A mobile radio communication system includes a plurality of base stations connected to a network through wire lines, and a plurality of mobile stations connected to the base stations through radio channels. The base and mobile stations share a plurality of radio frequencies and transmit at least one transmission signal at one of the shared radio frequencies. The transmission signal is arranged into time frames each having a plurality of time-division multiplexed slots. The base and mobile stations both include a control circuit having means for detecting unused time slots within the transmission signal and means for selecting one of the unused time slots. A radio channel establishing circuit establishes a channel between the mobile radio communication apparatus and the base station in accordance with the selected time slot.
摘要:
In a radio tele-communication system of this invention, at least one radio frequency is shared by a plurality of base stations and a plurality of mobile stations, a signal transmitted at the radio frequency has a time frame constituted by a plurality of time-divisionally multiplexed time slots, and time intervals for detecting timing shifts are set between the plurality of time slots. In at least either the base stations or mobile stations, a communication timing shift in a time slot currently used for communication is detected from a reception state in one of the time intervals for detecting timing shifts, and the communication timing of the corresponding time slot is corrected in cooperation with a station, with which communication is performed, on the basis of the communication timing shift detection result.
摘要:
A mobile radio communication system of this invention includes a plurality of base stations connected to a network through wire lines, respectively, and a plurality of mobile stations respectively connected to the base stations through radio channels. A plurality of radio frequencies are shared by the base and mobile stations. At least one of transmission signals having these radio frequencies is arranged as a time frame constituted by a plurality of time-divisionally multiplexed time slots. At least either of the base and mobile stations includes a use state determining section for determining the use states of each of the radio frequencies and each of the time slots on the basis of a received wave, a radio channel determining section, and a radio channel establishing section, which are arranged as function programs of software. On the basis of a determination result provided by the use state determining section, a radio frequency and a time slot for connecting the base and mobile stations by radio are determined, and a radio channel based on the determined radio frequency and time slot is established between the base and mobile stations.
摘要:
In a radio tele-communication system of this invention, each mobile station is designed to determine whether a control radio frequency can be used and to determine whether any free time slots are included in the time slots of a plurality of speech radio frequencies. A calling operation is performed by selecting a radio channel for the calling operation from the free time slots of the plurality of speech radio frequencies and the control radio frequency on the basis of the determination results.
摘要:
A speech communication apparatus of the present invention includes, in addition to an echo canceller for canceling an acoustic echo generated in a hands-free speech space, a chirp signal generating unit and a training unit. The chirp signal generating unit generates a chirp signal adequate for initial training of the echo canceller. The training control unit enables the chirp signal generating unit to generate a chirp signal, when a predetermined condition for starting hands-free speaking is satisfied, and a chirp tone corresponding to the chirp signal to be output as a volume-amplified tone from the hands-free speaker. The echo canceller performs initial training of the echo canceller based on the chirp tone.
摘要:
A radiotelephone of this invention comprises a sending-speech level varying circuit for varying the level of the sending-speech signal from the microphone and supplying the resulting signal and receiving-speech level varying means for varying the level of the receiving-speech signal demodulated by receiving means and supplying the resulting signal to the speaker, as well as a talking-mode setting section and a gain control circuit. At the talking-mode setting section, either the handset talking mode or the hand-free talking mode is set. At the gain control circuit, the gains of the sending-speech level varying circuit and receiving-speech level varying circuit undergo variable control according to the talking mode set by the talking-mode setting section. The gain control is carried out in such a manner that the gain becomes a first specific value when the handset talking mode has been set, and a second specific value larger than the first value when the hand-free talking mode has been set.
摘要:
A cordless telephone system includes a base unit connected to both a subscriber line and at least one branch telephone, and a mobile unit capable of being coupled to the base unit over a radio link. In the event that the handset of a branch telephone is switched on after a speech communication link has been established between the mobile unit and the subscriber line, an alarm may be provided to the user of the mobile unit. In addition, the user of the mobile unit may place the system in a holding state after a speech communication link has been established whereby the base unit and mobile unit maintain the speech communication link, but the mouthpiece of the mobile unit is disabled. In the event that the handset of a branch telephone is switched on, while the system is in a holding state, an alarm signal may be generated and output to a loud speaker at the mobile unit, and the mobile unit may be released from its holding state.
摘要:
A mobile radio communication system is provided with a base station apparatus connected to a wire circuit, a mobile radio station apparatus which is connected to the base station apparatus by a radio circuit, a mode designation device for selecting either an analog mode or a digital mode when radio communication is to be performed between the base station apparatus and the mobile radio station apparatus, and a mode-informing device for informing the base station apparatus of the mode designated by the mode designation device.
摘要:
A radio telephone system which comprises a base unit connected to a wired telephone line and a radio telephone set connected to the base unit through a radio link and which has an automatic re-calling function of automatically calling a party telephone set at intervals of a predetermined time when the parts telephone set is in a speech mode. This automatic re-calling operation is carried out only in the base unit under the released condition of the radio link between the base unit and the radio telephone set, and after the base unit confirms a response from the party telephone set, the radio link is established between the radio telephone set and the base unit.
摘要:
A mobile radio communication system is provided with a base station apparatus connected to a wire circuit, a mobile radio station apparatus which is connected to the base station apparatus by means of a radio circuit, a mode designation device for selecting either an analog mode or a digital mode when radio communication is to be performed between the base station apparatus and the mobile radio station apparatus, and a mode-informing device for informing the base station apparatus of the mode designated by the mode designation device.