Abstract: A noise suppressing circuit comprises: windings (W11, W12) inserted to conductor lines (3, 4) at respective points (P11a, P11b) and coupled to each other through a magnetic core (11); a winding (W13) coupled to the windings (W11, W12) through the core (11); capacitors (12, 13) having ends connected to the conductor lines (3, 4) at respective points (P12a, P12b) and the other ends connected to an end of the winding (W13); and windings (W14, W15) inserted to conductor lines (3, 4) at respective points (P13a, P13b) and coupled to each other through a magnetic core (14). These components reduce common mode noise. Capacitors (16, 17) reduce normal mode noise in cooperation with leakage inductances produced by the windings (W14, W15).

Abstract: A signal suppression filter (22) that inhibits high-frequency signals contained in power voltage and a signal separation filter (23) that prevents transmission of the high-frequency signals are provided in series on power lines (21A), (21B) connected to a power input terminal (T1), and a common-mode signal detection circuit (25) and a normal-mode signal detection circuit (26) are provided separately from each other. While bi-directionally blocking transmission of a high-frequency signal (noise) between the power supply and the device to be measured by the signal suppression filter (22) and the signal separation filter (23), the common mode signal and the normal mode signal generated in the device to be measured (3) and entering through a power output terminal (T2) are detecting separately. The analysis of the cause of occurrence of a high-frequency signal produced in the device to be measured (3) is facilitated, and proper noise countermeasure may be taken.

Abstract: A noise suppressing circuit (1) suppresses noise emerging from an electronic apparatus (2) and propagating through conductive lines (3a and 3b). The noise suppressing circuit (1) comprises a low-band noise reducing circuit (10) and a high-band noise reducing circuit (80). The low-band noise reducing circuit (10) is connected to the electronic apparatus (2) through the conductive lines (3a and 3b). The high-band noise reducing circuit (80) is cascade-connected to the low-band noise reducing circuit (10) and connected to conductive lines (4a and 4b) of a power line (4).

Abstract: A small and inexpensive signal detector is provided, which can be simply used for noise detection as a development tool for development engineers of systems and devices. A signal suppression filter (22) of inhibiting high-frequency signals contained in power voltage and a signal separation filter (23) of inhibiting transmission of the high-frequency signals are provided in series in power lines (21A), (21B) connected to a power input terminal (T1), and high-frequency signals contained in power voltage between a power output terminal (T2) and the signal separation filter (23) are outputted from signal output terminals (T3) to (T5). High-frequency signals from a power source can be blocked by the signal suppression filter (22) and the signal separation filter (23), so that influence of power noise on a measurement system can be eliminated.

Abstract: A common mode signal suppressing circuit comprises: a first winding (11) inserted to a conductor line (3); a second winding (12) that is inserted to a conductor line (4) and coupled to the first winding (11) through a magnetic core (10) and that suppresses common mode signals in cooperation with the first winding (11); and a third winding (13) coupled to the first and second windings (11, 12) through the core (10). The common mode signal suppressing circuit further comprises a phase-inverted signal transmitting circuit (15) connected to the third winding (13) and to the conductor lines (3, 4). The phase-inverted signal transmitting circuit (15) detects a common mode signal on the conductor lines (3, 4), and supplies a phase-inverted signal to the third winding (13), the phase-inverted signal having a phase opposite to the phase of the common mode signal.

Abstract: A noise suppressing circuit comprises: a winding (11a) inserted to a conductor line (3) at a first point (P11); a winding (11b) coupled to the winding (11a); an injection signal transmission path (19); and an inductance element (13). The injection signal transmission path (19) has an end connected to the conductor line (3) at a second point (P12) and the other end connected to a conductor line (4). The winding (11b) is inserted somewhere along the injection signal transmission path (19). The injection signal transmission path (19) transmits an injection signal that is generated based on a signal corresponding to noise detected on the conductor line (3) and that is injected to the conductor line (3) to suppress the noise. The inductance element (13) is inserted to the conductor line (3) at a point between the point (P11) and the point (P12). The number of turns of the winding (11b) is greater than that of the winding (11a).

Abstract: A normal mode noise suppressing circuit comprises: a noise suppressing section (10) provided on conductor lines (3, 4); and a capacitor (31) having an end connected to the conductor line (3) and the other end connected to the conductor line (4). The noise suppressing section (10) comprises: a winding (15a) inserted to the conductor line (3); a winding (15b) coupled to the winding (15a) through a magnetic core (15c); an injection signal transmission path (19); a capacitor (16); and an inductance element (18). The injection signal transmission path (19) has an end connected to the conductor line (3) and the other end connected to the conductor line (4). The winding (15b) and the capacitor (16) are inserted somewhere along the injection signal transmission path (19). The inductance element (18) is inserted to the conductor line (3) at a point between the winding (15a) and the node between the injection signal transmission path (19) and the conductor line (3).

Abstract: A noise suppressing circuit comprises: windings (W11, W12) inserted to conductor lines (3, 4) at respective points (P11a, P11b) and coupled to each other through a magnetic core (11); a winding (W13) coupled to the windings (W11, W12) through the core (11); capacitors (12, 13) having ends connected to the conductor lines (3, 4) at respective points (P12a, P12b) and the other ends connected to an end of the winding (W13); and windings (W14, W15) inserted to conductor lines (3, 4) at respective points (P13a, P13b) and coupled to each other through a magnetic core (14). These components reduce common mode noise. Capacitors (16, 17) reduce normal mode noise in cooperation with leakage inductances produced by the windings (W14, W15).

Abstract: A modem for power-line communications (20A) comprises input/output terminals (71a and 71b) and input/output terminals (72a to 72d). The input/output terminals (71a and 71b) are connected to a power line and perform input and output of power-line communications signals. The input/output terminals (72a to 72d) perform input and output of data signals from and to a communications apparatus through a cable. The modem (20A) further comprises: a modem main body (73); a common mode filter (80) provided between the modem main body (73) and the input/output terminals (71a and 71b); and a common mode filter (90) provided between the modem main body (73) and the input/output terminals (72a to 72d).

Abstract: A noise suppressing circuit (1) suppresses noise emerging from an electronic apparatus (2) and propagating through conductive lines (3a and 3b). The noise suppressing circuit (1) comprises a low-band noise reducing circuit (10) and a high-band noise reducing circuit (80). The low-band noise reducing circuit (10) is connected to the electronic apparatus (2) through the conductive lines (3a and 3b). The high-band noise reducing circuit (80) is cascade-connected to the low-band noise reducing circuit (10) and connected to conductive lines (4a and 4b) of a power line (4).

Abstract: A power line communication system comprises an indoor power line and one or more power line branching apparatuses connected to the indoor power line. The power line branching apparatus comprises a communication channel that is branched off from the indoor power line and connectable to a power line communication device, and a power supply channel that is branched off from the indoor power line and connectable to electrical equipment. The power line branching apparatus further comprises an impedance matching circuit and a normal mode filter circuit. The impedance matching circuit is provided on the power supply channel, and sets the impedance of the indoor power line to a predetermined value. The normal mode filter circuit is provided on the power supply channel, and reduces normal mode noise occurring from the electrical equipment connected to the power supply channel.

Abstract: A common mode signal suppressing circuit comprises: a first winding (11) inserted to a conductor line (3); a second winding (12) that is inserted to a conductor line (4) and coupled to the first winding (11) through a magnetic core (10) and that suppresses common mode signals in cooperation with the first winding (11); and a third winding (13) coupled to the first and second windings (11, 12) through the core (10). The common mode signal suppressing circuit further comprises a phase-inverted signal transmitting circuit (15) connected to the third winding (13) and to the conductor lines (3, 4). The phase-inverted signal transmitting circuit (15) detects a common mode signal on the conductor lines (3, 4), and supplies a phase-inverted signal to the third winding (13), the phase-inverted signal having a phase opposite to the phase of the common mode signal.

Abstract: In a power line noise filter, a detection circuit detecting variations in electric current in two conductive lines of an electric power line, thereby detecting common mode noise that causes a change in electric current in the power line. A phase-inverted signal generation circuit then generates a phase-inverted signal whose is inverted to that of the noise detected by the detection circuit. Further, an injection circuit causes a change in electric current corresponding to the phase-inverted signal, for the two conductive lines of the electric power line. The common mode noise causing a change in electric current in the electric power lines is thereby canceled.

Abstract: A power line communication system comprises an indoor power line and one or more power line branching apparatuses connected to the indoor power line. The power line branching apparatus comprises a communication channel that is branched off from the indoor power line and connectable to a power line communication device, and a power supply channel that is branched off from the indoor power line and connectable to electrical equipment. The power line branching apparatus further comprises an impedance matching circuit and a normal mode filter circuit. The impedance matching circuit is provided on the power supply channel, and sets the impedance of the indoor power line to a predetermined value. The normal mode filter circuit is provided on the power supply channel, and reduces normal mode noise occurring from the electrical equipment connected to the power supply channel.

Abstract: In a power line noise filter, a detection circuit detecting variations in electric current in two conductive lines of an electric power line, thereby detecting common mode noise that causes a change in electric current in the power line. A phase-inverted signal generation circuit then generates a phase-inverted signal whose is inverted to that of the noise detected by the detection circuit. Further, an injection circuit causes a change in electric current corresponding to the phase-inverted signal, for the two conductive lines of the electric power line. The common mode noise causing a change in electric current in the electric power lines is thereby canceled.

Abstract: A lighting apparatus for a discharge lamp (15) has a power adjustment unit (11,13) for adjusting electrical power to be supplied to the discharge lamp, an ignition pulse circuit (17) for producing at least one ignition pulse to be applied to the discharge lamp, and a computer control circuit (19) electrically connected with the power adjustment unit and the ignition pulse circuit. The computer control circuit (19) controls the power adjustment unit and the ignition pulse circuit so that at first the power adjustment unit (11,13) supplies an idling voltage to the discharge lamp, then the ignition pulse circuit (17) lights up the discharge lamp by applying at least one ignition pulse to the discharge lamp, and thereafter the power adjustment unit (11,13) controls lamp power of the discharge lamp to a target lamp power.

Abstract: An inductance element of the type that includes a coil bobbin having flanges at the ends thereof, a pair of pot cores engaging the bobbin, and a fastening member for fastening together the pot cores and bobbin. At least one of the bobbin flanges includes a joining part that extends outwardly from the bobbin flange and engages both the adjacent one of the pot cores and the fastening member to prevent relative rotation of the bobbin and adjacent pot core and fastening member. One of the bobbin flanges may include a stepped part having pins extending therefrom for making electrical connection to the inductance element. The stepped part is spaced from the bobbin flange, and connection wires may extend within the space.

Abstract: The new structure of a ferrite core for the use of a power transformer and/or a choke coil has been found. The core is assembled by a pair of identical core halves, and each of core half comprises (a) a circular center boss(12), (b) a pair of outer walls(14,16) positioned at both the sides of said boss(12) so that a fan-shaped empty space is provided between the circular boss(12) and a pair of outer walls(14,16) for mounting a coil, (c) a pair of base plates(18,20) coupling said boss(12) with said outer walls(14,16) at the extreme end of those members so that those members conform substantially with the E-shaped structure, (d) the other extreme end of said boss(12), the outer walls(14,16) and the base plates(18,20) residing on a single plane, (e) each of said outer walls(14,16) being essentially rectangular with the external linear wall and the inner curved wall which is coaxial with the circular boss(12), and the width(d.sub.2) of said external linear wall is larger than the diameter(d.sub.