Showing papers on "Wireless published in 1977"
Patent•
16 Aug 1977
TL;DR: In this paper, a tire pressure sensor is connected to a radio frequency transmitter which transmits signals to the operator station representing the condition of the vehicle's tires, and the transmitter receives its power from an electromagnetic coil energized by rotation of the wheel.
Abstract: A tire pressure sensor is connected to a radio frequency transmitter which transmits signals to the operator station representing the condition of the vehicle's tires. The transmitter receives its power from an electromagnetic coil energized by rotation of the vehicle's wheel. In one embodiment, the coil is mounted on the vehicle's wheel and a magnet is mounted on the chassis so that rotation of the wheel energizes the RF transmitter.
63 citations
01 May 1977
TL;DR: In this article, the feasibility of developing compact transmit antennas and/or other means to efficiently couple VLF to MF band radio energy between portable wireless communication units in coal mines is investigated.
Abstract: An investigation is made of the feasibility of developing compact transmit antennas and/or other means to efficiently couple VLF to MF band radio energy between portable wireless communication units in coal mines. The completely wireless communication range between two portable radios equipped with practical size reference loop antennas in representative coal mine environments is estimated. Antenna technology is assessed with respect to transmit moment, range, intrinsic safety, battery and wearability requirements to determine the most suitable antenna types for use by miners. It is concluded that air-core bandolier loop antennas, and perhaps ferrite-loaded loop antennas, having peak transmit moments of about 2.5 ampere-sq m will be the most effective antennas for portable units. This choice, however, will not allow the range goal of 1,350 feet to be attained in mines having unfavorable signal attenuation and noise environments. Rectangular air-core loops are compared with grounded horizontal-wire and vertical-wire mode exciters for fixed station applications. The potential for significantly increasing the wireless communication range by inductively coupling to communications and power lines in a mine is evaluated and found to be considerable based on theoretical coupling equations. The theoretical performance of a hybrid noise cancelling diversity receiving technique that utilizes both themore » electric and magnetic field components of the ambient noise to improve the receiver output signal-to-noise ratio under certain adverse conditions is estimated and shown to be favorable when the magnetic and electric field noise components are highly correlated.« less
8 citations
Patent•
19 Feb 1977
TL;DR: In this article, the authors proposed a method to make it possible to transmit signals by utilizing the exsiting power lines, telephone lines, pipe lines of water system etc., which can be found in the following:
Abstract: PURPOSE:To make it possible to transmit signals by utilizing the exsiting power lines, telephone lines, pipe lines of water system etc.
5 citations
Patent•
11 Apr 1977
TL;DR: In this article, the authors proposed a method to ensure a simultaneous information transmission and reception between two wireless transmissions and reception stations through single frequency channel by having time compression and extension of transmission signal.
Abstract: PURPOSE:To ensure a simultaneous information transmission and reception between two wireless transmission and reception stations through single frequency channel by having time compression and extension of transmission signal.
4 citations
16 Mar 1977
TL;DR: An underground communications system has been installed in Bethlehem Mines Corporation's Grace Iron Mine as mentioned in this paper, which provides communications for trackless vehicles and roving personnel without the requirement for a dispatcher UHF/VHF repeaters are combined with coaxial "leakyfeeder" and twin-lead transmission line to form an operational and emergency communication network not previously found in mine communication systems Key functions are evacuation alarming, personnel paging and communications with maintenance personnel and the underground ambulance
Abstract: An underground communications system has been installed in Bethlehem Mines Corporation's Grace Iron Mine The system provides communications for trackless vehicles and roving personnel without the requirement for a dispatcher UHF/VHF repeaters are combined with coaxial "leaky-feeder" and twin-lead transmission line to form an operational and emergency communication network not previously found in mine communication systems Key functions are evacuation alarming, personnel paging and communications with maintenance personnel and the underground ambulance
3 citations
Patent•
25 Mar 1977
TL;DR: In this article, the authors propose to enable the communication with the same only frequency among a plural number of stations by determining the timing area of transmitting and receiving mode for each station by the electromagnetic wave of initial transmitting station.
Abstract: PURPOSE:To enable the communication with the same only frequency among a plural number of stations by determining the timing area of transmitting and receiving mode for each station by the electromagnetic wave of initial transmitting station.
3 citations
Patent•
07 Apr 1977
2 citations
Patent•
14 Jan 1977
TL;DR: In extension equipment providing wireless transceivers at subscriber telephone terminal, illegal use by third parties by other wireless telephone equipment using same electrical wave is prevented as discussed by the authors. But, this is not the case in our case.
Abstract: PURPOSE:In extension equipment providing wireless transceivers at subscriber telephone terminal, illegal use by third parties by other wireless telephone equipment using same electrical wave is prevented
2 citations
Patent•
30 Aug 1977
TL;DR: In this paper, the authors proposed a solution to solve a problem of a conventional mobile communication system, where an operating clock frequency of a data processing section is reduced to decrease production of a noise from the data processing sections, whose data processing cannot catch up with high speed data processing resulting in causing disabled high-speed data communication.
Abstract: PROBLEM TO BE SOLVED: To solve a problem of a conventional mobile communication system, where an operating clock frequency of a data processing section is reduced to decrease production of a noise from the data processing section, whose data processing cannot catch up with high-speed data processing resulting in causing disabled high-speed data communication. SOLUTION: When a measured error rate from an error rate measurement means 6 is higher than a preset 1st threshold value and a measured electric field strength from a received electric field strength measurement means 5 is higher than a preset 2nd threshold value, a control means 9 compares a reception frequency band with a noise frequency band as to whether or not they are matched with each other and makes an increase request of transmission power to a base station through a transmission means 3 when both the frequency bands are coincident. Upon the receipt of the transmission power increase request from a wireless mobile terminal, the base station increases the transmission power to transmit a wireless wave with the increased power to the wireless mobile terminal. Since the power of the desired wave is increased more than that before making the transmission power increase request, the ratio of the desired wave in the desired wave versus undesired wave ratio is increased and the reception sensitivity of the wireless mobile terminal can be enhanced.
1 citations
01 May 1977