摘要:
A radio apparatus having a unit for receiving a first signal from a first transceiver compressed in time by a predetermined rate, a unit for reproducing a first original signal from the first signal, a unit for receiving a second signal from a second transceiver compressed by the predetermined rate during the reception period of the first transceiver, a unit for reproducing a second original signal from the second signal, and a unit for adding the first and second original signals and outputting the added signal.
摘要:
A communication system for performing bidirectional communications substantially simultaneously between a telephone line and a radio communication system by using a single-frequency carrier. A base station includes a first radio transceiver and a line connector disposed between the first radio transceiver and the telephone line. A terminal station includes a second radio transceiver. Each of the first and second radio transceivers has a control unit, a transmitter unit including a signal compressor, a synchronizing signal generator and a modulator, and a receiver unit including a signal expander. The control unit sets the line connector to an interconnecting state in response to a connection request signal from the telephone line or the terminal station, while establishes a communication enabling state between the telephone line and the terminal station during a connection processing period. After the communication enabling state has been set up, a speech enabling state is established between the telephone line and the terminal station. The connection processing period is changed over to a speech period after the communication enable state has been established, to thereby allow communication between the telephone line and the terminal station.
摘要:
A radio relay communication system wherein a signal transmitted from active one of a plurality of radio units is received and recorded. When the transmission operation of the particular radio unit stops, the recorded signal is reproduced and transmitted by a relay unit, and another radio unit receives the signal from the relay unit. A relay start signal is transmitted from the first radio unit. and is received by the relay unit. In response to the relay start signal, the relay unit generates a sync signal of predetermined period. The first radio unit, in accordance with the reception of the sync signal, transmits an input signal as compressed to less than one half along the time axis. The relay unit alternates between the period of receiving the compressed signal and the period of transmission in synchronism with the sync signal. The compressed signal transmitted from the relay unit during the transmission period is received by the second radio unit and expanded along the time axis thereby to reproduce the input signal.
摘要:
A time-divisional duplex radio communication apparatus includes the steps of adding an interrupt enable signal to the compressed voice signal in place of the time-divisional synchronizing signal at a predetermined period in a radio communication apparatus served as a calling station, functioning the period corresponding to the time-divisional synchronizing signal as a reception period without having to add the time-divisional synchronizing signal to the compressed voice signal at the next transmission period if the interrupt enable signal from the calling station is received in a radio communication apparatus served as the called station, generating the interrupt request signal a predetermined time later than the reception of the interrupt enable signal of the calling station and transmitting the interrupt request signal in the reception periods of the calling station and the called station in a radio communication apparatus served as an interrupting station, indicating occurrence of an interrupt in response to the reception of the interrupt request signal in the radio communication apparatuses served as the calling station and the called station.
摘要:
In radio communication system in which single frequency simultaneous transmission and reception is performed, a speech audio signal is divided by a predetermined time interval. A transmission time and a reception time are allotted in the predetermined time. A time-compressed signal is transmitted during the transmission time, and a time-compressed signal transmitted from other transceiver is received during the reception time and it is decompressed to the original length. The transmission time and the reception time are alternately repeated to transmit and receive the audio signals substantially simultaneously by a single frequency, and the audio signal is reproduced from the received signal. When communication with a telephone set is to be established, a DTMF signal is used as a dialing signal to call the telephone set from the transceiver. The DTMF signal is time-compressed and then transmitted along with the speech signal. A transmission timing of the DTMF signal is controlled, and the generated DTMF signal is temporarily stored in a memory. When the transmission of the DTMF signal can be completed before the transmission time is switched to the reception time is determined, and if it can, the DTMF signal is read from the memory and transmitted.
摘要:
There is disclosed a surge discriminating and locating system having at least one master station and at least one slave station. The system comprises surge receiving means for receiving surges which occur on a power transmission line, locating means for locating a point where the surge occurs, digitizing means for digitizing said surge into a digital signal, extraction means for extracting from said digital signal the characterized portions thereof as information representative of the surge waveform, memory means for storing predetermined reference information concerning the nature of surges, and discriminating means for comparing said information representative of the surge wave form with said reference information stored in said memory means to discriminate the kind of surge.
摘要:
A surge locating system and a method thereof which can accomplish the surge locating with high accuracy and with relatively simple structure. When the surge occurs, the voltage is generated on the neutral point of Y-connected three-phase alternating current transmission line because of losing a voltage balance on the three-phase alternating current transmission line. The surge locating can be accomplished by detecting the voltage generated in the neutral point. The neutral point is grounded, and the surge locating system according to the present invention is installed between the neutral point and the grounding point. The voltage generated in the neutral point is introduced into the surge locating system and the detecting time thereof is stored. This detecting time is stored in the respective stations, and the surge point can be located based on the detecting time difference between the stations.
摘要:
A radio communication apparatus for transmitting a voice signal and a data signal in a multiplex form. The transmitting side of the radio communication apparatus includes: a sampling unit for sampling the voice signal and the data signal and generating a digital voice signal and a digital data signal; a time division unit for dividing the digital voice signal and the digital data signal on the basis of a predetermined period; a modulation unit for modulating the divided digital data signal by a predetermined digital modulation scheme; a unit for compressing the divided digital voice signal at a predetermined compression factor and generating a compressed voice signal; a unit for combining the divided and compressed voice signal and the divided and digitally modulated digital data signal and generating a multiplex signal; and a unit for modulating a carrier signal by the multiplex signal and transmitting the modulated carrier signal as a transmission signal.
摘要:
A duplex voice communication radio transmitter-receiver according to the present invention is provided with a low-pass filter arranged before a time compressing device in a transmitter section for cutting off a higher frequency portion of the band of a voice signal thus to decreasing the maximum modulation frequency of the same to less than a half so that it can be operated with the use of an assigned, single frequency transmission radio wave of which frequency band is legally limited, improved in the utilization of frequencies, minimized in the delay of communication signals, and enhanced in the articulation and intelligibility of a reproduced voice sound.
摘要:
A transceiver having a transmitting unit and a receiving unit for performing substantially simultaneous communication with another transceiver in both directions by using a single frequency carrier. The transceiver includes a unit for generating a synchronizing signal for alternately switching between a transmission time period and a reception time period of the transceiver at a predetermined period, a signal processing unit for converting an input signal into a compressed signal by compressing a time axis of the input signal by a predetermined ratio, and affixing the synchronizing signal to the compressed signal, a unit for supplying the compressed signal with the synchronizing signal to the transmitting unit during the transmission time period, and a unit for reproducing an original signal from a signal transmitted from the other transceiver and received by the receiving unit during the reception time period, by expanding a time axis of the signal by a predetermined ratio. The transceiver further includes a signal detecting unit for detecting an absence/presence of the input signal and generating an output signal corresponding the absence/presence, and a control unit for controlling the operation of the signal processing unit in accordance with the output signal of the signal detecting unit. The control unit controls operation of the signal processing unit to transmit only a signal related to the synchronizing signal to the other transceiver, when the signal detecting unit generates the output signal representing an absence of the input signal for a predetermined time period.