ASYNCHRONOUS POWER LINE TRANSMISSION APPARATUS

Abstract: An asynchronous power line transmission apparatus generates impulse radio data signals at rising edges and falling edges of data pulses and transmits the impulse radio data signals via a power line to other asynchronous power line transmission apparatus. Further, the asynchronous power line transmission apparatus receives impulse radio data signals transmitted from the other asynchronous power line transmission apparatus, clips levels of received positive and negative impulse radio data signals in order to remove a noise inserted into the received impulse radio data signals, respectively, reconstructs impulse pairs consisting of a positive set impulse from the positive impulse radio data signals and a positive reset impulse from the negative impulse radio data signals, and reproduces the data pulses transmitted from the other asynchronous power line transmission apparatus by selecting only a first pulse of each impulse pair if the selected pulse is a set pulse, a high level signal pulse is generated and if the selected pulse is a reset pulse, a low level pulse signal is generated.

Description: ASYNCHRONOUS POWER LINE TRANSMISSION APPARATUS TECHNICAL FIELD The present invention relates to a data transmission apparatus through a network, and more particularly, to an asynchronous power line transmission apparatus for transmitting an impulse radio data signal through a power line. BACKGROUND ART Power line communication refers to a communication method using an AC 110V/220V power line as a communication media, for which communication equipments are communicated through the power line without installation of an extra telephone line or a dedicated line for data communication. A power line transmission apparatus in use for the power line communication is applied to a high-speed power line communication modem, a power line communication unit of various sensors or driving apparatus, a unit of a sensor for measuring the physical quantity of electric power water or gas, a power line communication unit for constructing a high speed communication network (i.e., LAN, etc ) or for an industrial automation, or an applied field such as an Internet automatic telemetering Recently, in order to use the power hne as a communication channel, a research has been conducted on power line transmission characteristics by an FSK method or a PSK method And, the current trends show that apparatuses adopting the methods are being put to a practical use Generally, the power line communication systems employ a carrier synchronizing method to per orm communication However the communication method adopted to the power line transmission apparatus in accordance with the conventional art has problems that the reliability of communication is degraded according to the load variation due to the ON/OFF operation of various electric 10 apparatuses connected to the power line and the inherent noise environment generated from the electric apparatuses That is the communication method such as the FSK or the PSK adopted between transmitting/receiving terminals is disadvantageous in that due to the noise environment around the power line and the loading l effects of various loads connected to the power line the impedance that is a line constant, is much varied, so that a signal transmission rate is low and a signal detection is not so reliable The low signal transmission rate through the power line and the low reliability in the signal detection are also resulted from a difficulty in synchronously 0 controlling a signal transmitted through the power line because of the hne characteristics change as a transmission channel or the noise Accordingly in order to cope with the load variation and the noise environment the communication system should be noise- resistant and the problem of the synchronization controlling should be solved. In order to improve such conventional problems, the present invention proposes a method of transmitting a 1 -cycle sinusoidal shock pulse (referred to as an 'impulse data signal, hereinafter), that is, an 5 impulse data signal. The impulse data signal refers to a signal of which time average is O' and its pulse time width is below scores of [nsec], having characcteristics that it is evenly transmitted regardless of variation of the impedance, that is, a line constant, due to the environmental noise 10 of the power line, working and variation of loads of various electrical devices Therefore, an object of the present invention is to provide an asychronous power line transmission apparatus which is capable of transmitting a data at an ultra-high speed with reliability by employing a i signal detecting method of asychronous system for the impulse data signal transmitting method, and capable of simply constructing a transmitting/receiving apparatus DETAILED DESCRIPTION OF THE INVENTION 0 To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an asynchronous power line transmission apparatus including a transmitting circuit having an impulse data signalizing circuit for converting a transfer data pulse from a digital terminal such as a personal computer to an impulse data signal and transmitting the impulse data signal to the other party through a power line, and a receiving circuit having an amplifying and level clipping unit for receiving an impulse data signal transmitted from the 5 other party through the power line by its receiving terminal, removing a noise amplifying the impulse data signal to a certain level and clipping the impulse data signal by above a certain level, an impulse data signal separating and detecting unit for separating a positive (+) impulse and a negative (-) impulse of a transferred pulse corresponding a positive 10 edge and a negative edge, and a pulse reproducing unit for setting the positive (+) pulse interval of the impulse data signal separating and detecting unit as a positive (+) set pulse and the negative (-) pulse interval as a positive (+) reset pulse, arranging the pulses to set-reset pair of pulses and reset-set pair of pulses corresponding to 1 -cycle i s impulse data signal on time basis, selecting only a first pulse of each pair of pulses so that if the selected pulse is a set pulse a high level signal pulse is generated while if the selected pulse is a reset pulse, a low level pulse signal is generated, to thereby reproduce a transfer data pulse signal and transmit it to a PC interface 0 In addition, in the asynchronous power line transmission apparatus of the present invention, the positive edge and the negative edge of the data pulse are converted to an impulse data signal having a mutually inverted potential to be transmitted so that the transmission characteristics are constantly maintained regardless of the background noise around the power line or the load variation of the power line Also, in the asynchronous power line transmission apparatus of the present invention, though a random impulse noise pulse that can be generated when the load is operated or varied in the power line has a s higher level than the size of the power line background noise that has an amplitude of [μV] unit by about 20-50 [dB] (10-300 times), since the duration of the impulse noise pulse generally shows a low frequency characteristic that is indicated by [μsec], the impulse noise pulse can be separated with the impulse data signal of a high frequency 10 characteristic of which duration is below scores of nano seconds [nsec] and can be removed by the frequency separating method Therefore, as the noise is completely removed by a noise removing unit that employs a cascaded 2-stage processing frequency separating method in consideration of even a random particular noise, a i s reliability in reproducing the data pulse by the data pulse reproducing unit is highly improved and a ultra-high data transmission can be accomplished by the transceiver system of the impulse data signal having the duration of below [nsec] 0 BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention In the drawings: Figure 1 is a schematic view showing a construction of a network adopting a general power line transfer system in accordance with a conventional art; Figure 2 is a schematic view showing a construction of a power line transmission apparatus in accordance with the present invention, and Figure 3 is a view showing waveforms of input and output signal of each circuit of Figure 2 in accordance with the present invention DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Figure 1 is a schematic view showing a construction of a network adopting a general power line transmission system which includes a single-phase two-wire power line 104 for supplying power, power line transmitting/receiving devices 103 and 105 for transmitting and receiving data through the power line 104, and interface units 102 and 106 for transmitting and receiving data between terminal equipments such as personal computers 101 and 107. Figure 2 is a schematic view showing a construction of a power line transmission apparatus in accordance with the present invention As shown in the drawing, the asychronous power line transmission apparatus of the present invention includes a transmitting circuit consisting of an impulse circuit 130 for respectively converting a positive edge and a negative edge of an output pulse to an impulse pulse (an impulse signal) having a constant duration so as to transfer a data pulse transmitted by a clock generator of a predetermined frequency and an impulse data signal circuit 135 for receiving the impulse signal and converting it to an impulse data signal suitable for transmission through a power line 140, a receiving circuit consisting of a receiving signal transforming and noise removing unit 150 for receiving the impulse data signal transmitted from the other party (impulse data signal circuit 135) through the power line 140 and removing its noise, an amplifying and level clipping unit 160 for amplifying the impulse data signal outputted from the receiving signal transforming and noise removing unit 150 to a certain level and clipping the amplified impulse data signal by above a certain level to remove a noise again, an impulse data signal separating and detecting unit 170 for separating the output signal from the amplifying and level clipping unit 160 into a positive (+) impulse data signal and a negative (-) impulse data signal corresponding to the positive edge and the negative edge of the data pulse and detecting the same, and a data pulse reproducing unit 180 for setting the positive (+) impulse interval of the impulse data signal as outputted from the impulse data signal separating and detecting unit as a positive (+) set pulse and the negative (-) impulse interval as a positive (+) reset pulse, arranging the pulses to set-reset pair of pulses and reset-set pair of pulses corresponding to 1 -cycle impulse data signal on time basis, and selecting only the first pulse of each pair of pulses to reproduce a data pulse signal, and an interface unit 120 for matching the impulse circuit 130 of the transmitting circuit and the data pulse reproducing unit 180 of the receiving circuit with a personal computer (PC) 110 Referring to the impulse data signal, its time average is '0' and its signal duration is below scores of [nsec] Also, the impulse data signal is transmitted evenly, not being influenced by the background noise around the power line or the variation of the impedance, that is, a line constant, generated by the operation of and the change in the load of various electrical apparatuses connected to the power line The impulse data signal circuit 135 includes a pulse transformer The impulse signal outputted from the impulse data signal circuit 135 is a shock pulse signal of 1 -cycle or of 1/2-cycle sinusoidal that has been mutually phase-inverted The operation and effect of the asynchronous power line transmission apparatus constructed as described above in accordance with the present invention will now be explained in detail When a data pulse as shown in Figure 3A is generated and transmitted by a clock generator of the PC 110 having a certain data transmission rate through the interface 120 to the transmitting circuit, the impulse circuit of the transmitting circuit generates a positive (+) impulse having a predetermined duration corresponding to the positive edge and the negative edge of the data pulse and outputs it to the impulse data signal circuit 135 Upon receipt of the impulse signal from the impulse circuit 130, as shown in Figure 3B, the impulse data signal circuit 135 converts the positive edge of the data pulse to an impulse data signal with 1 cycle of positive (+) and negative (-) (or 1/2 cycle of positive (+)) having a certain duration from scores of pico seconds ([psec]) to scores of nano seconds ([nsec]) In addition, the impulse data signal circuit 135 converts the negative edge of the data pulse to a phase-inverted (the opposite to the phase of a signal obtained from the positive edge) impulse data signal with 1 cycle of negative (-) and positive (+) (or 1/2 cycle of negative (-)) having a certain duration from scores of pico seconds ([psec] to scores of nano seconds ([nsec]) And then, the impulse data signal circuit 135 transmits the generated impulse data signal through the power line 140 to the other party The receiving signal transforming and noise removing unit 150 detects the impulse data signal as shown in Figure 3B transmitted through the power line 140, receives a signal through the pulse transformer, data, removes added power line noise by using a cascaded 2-stage frequency separating method, and then outputs it to the amplifying and level clipping unit 160 Upon receipt of the impulse data signal from the receiving signal transforming and noise removing unit 150, the amplifying and level clipping unit 160 amplifies the impulse data signal to a certain level and clips the amplified impulse data signal to have a signal above a certain level so as to remove a noise When clipping, the positive (+) clipping impulse data signal, as shown in Figure 3C, is outputted as a positive (+) phase, while the negative (-) clipping impulse data signal, as shown in Figure 3D, is phase-inverted and outputted The impulse data signal separating and detecting unit 170 outputs the positive (+) impulse and the negative (-) impulse (a set signal and a reset signal) that were separated and detected by the amplifying and level clipping unit 160 to the data pulse reproducing unit 180 Then, the data pulse reproducing unit 180, as shown in Figure 3E, arranges the positive (+) pulse and the negative pulse (-) ( the set signal and the reset signal) as separated and detected as a pair of the positive (+) set and reset pulses and a pair of the positive (+) reset and a set pulses corresponding to the 1 -cycle impulse data signal on a time basis At this time, the data pulse reproducing unit 180 selects only a first pulse of each pulse pair, so that when the selected pulse is a set pulse the data pulse reproducing unit 180 generates a high level pulse signal while the selected pulse is a reset pulse, it generates a low level pulse signal, to thereby reproduce the data pulse signal transmitted through the power line and output the reproduced data pulse signal through the interface unit 120 to the PC 110 In this manner, the asynchronous power line transmission apparatus transmits and receives the data through the power line In the asynchronous power line transmission apparatus of the present invention as operated as described above, the amplitude of the random impulsive noise pulse that may be generated when a load of the power line is varied has a high level of about 20~50dB, higher by 10-300 times than the amplitude of the power line background noise having an amplitude of micro voltage unit ([μV]), and the time-width of the impulsive noise pulse has a low frequency characteristic represented in a micro seconds ([μsec]) But since the time-width of the impulse data signal has a high frequency characteristic below scores of nano seconds ([nsec]), the noise pulse can be removed by filtering through the frequency separating method Accordingly, the noise removing unit adopting the cascaded two-stage processing of frequency separating method in consideration of even the random particular noise completely removes the noise, so that the data pulse reproducing unit can reproduce the reliable data pulse Also, the data can be transmitted at an ultra-high speed owing to the transmitting method that transmits the impulse data signal having a time-width of below scores of nano seconds ([nsec]) INDUSTRIAL APPLICABILITY As so far described, according to the asynchronous power line transmission apparatus of the present invention thanks to the low signal attenuation characteristic of the power line and little signal decaying effect in an electric concentric-plug with respect to the impulse data signal transmitted having a certain time-width, a low level signal can be transmitted through the power line Also since the level of the transmitted signal is low, an electromagnetic interference (EMI) problem does not occur, and when the data is transmitted to a remote location, its constant signal transmission characteristic can be maintained Moreover, the asynchronous power line transmission apparatus can be applied to an ultra-high speed power line communication network (LAN) construction within 2-3 km radius, a CCTV network construction, a factory automation construction, an underground wireless relay network construction, and home appliance information network construction, or also can be applied to control various electromechanical apparatus and to a telemetering field As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims or equivalence of such meets and bounds are therefore intended to be embraced by the appended claims

Claims: CLAIMS 1 An asynchronous power line transmission apparatus comprising an impulse data signal means for converting a data pulse outputted from a digital terminal such as a personal computer to an impulse data signal having a certain duration and transmitting the impulse data signal to the other party. 2 The apparatus according to claim 1 further comprising a level clipping means for receiving an impulse data signal transmitted from the other party and clipping the received impulse data signal by above a certain level 3 The apparatus according to claim 2 further comprising an impulse data signal separating means for separating the level clipped impulse data signal into a positive (+) impulse data signal and a negative (-) impulse data signal and accordingly outputtmg a data pulse signal 4 The apparatus according to claim 3 further comprising a noise removing means for removing a noise pulse from the outputted signal after being level-clipped 5 The apparatus according to claim 4, wherein the noise removing means employs a frequency separating method to remove the noise pulse 6 The apparatus according to claim 3 further comprising a signal producing means for setting a positive (+) set signal and reset signal corresponding to a positive (+) and a negative (-) impulse interval as a positive (+) set-reset pulse pair and a positive (+) reset-set pulse pair corresponding to 1 -cycle impulse data signal on a time basis and selecting only a first pulse of each pulse pair to reproduce a transmission data pulse 7 The apparatus according to claim 1 , wherein the positive edge of the data pulse is set as an impulse data signal having 1 -cycle of positive (+) and negative (-) and the negative edge of the data pulse is set as an impulse data signal having 1 -cycle of phase- inverted negative (-) and positive (+), for transmission

Inventors: JOO CHANG-BOK, KIM SEUNG-DOL, JOO, CHANG-BOK, KIM, SEUNG-DOL
Applicants: JOO CHANG BOK, KIM SEUNG DOL, JOO, CHANG-BOK, KIM, SEUNG-DOL
Application year: 2000
Main classification: G08C19
IPC codes: G08C19, H04B3, H04L25