Abstract: A multilayer circuit board having a signal and power isolation circuit, which can suppress the capacitive coupling between a chip inductor and a ground layer below the chip inductor and also suppress the characteristic impedance change occurring in a mounting pad on a microstrip line. Portions of the inner-layer ground below both the mounting pad on the microstrip line and the chip inductors connected to the mounting pad are separately removed respectively as the signal transmission characteristic compensation removal portion, which is formed by removing a portion having a predetermined area and situated immediately below the mounting pad, and the inductor characteristic compensation removal portion, which is formed by removing a mounting-surface-below portion having a predetermined area and situated immediately below the chip inductors.

Abstract: A transmission system capable of improving transmission characteristics in a low frequency range and having reduced size. A transmission system for superimposing power on a signal transmission path between a first circuit module and a second circuit module includes a first capacitor between the transmission path and a first interface IC in the first circuit module, a second capacitor between the transmission path and a second interface IC in the second circuit module, a first inductor between a first power supply circuit in the first circuit module and the transmission path, and a second inductor between a second power supply circuit in the second circuit module and the transmission path. A capacitance value of the first capacitor and a capacitance value of the second capacitor differ from each other. Inductance values of each of the first and second inductors are in a range from 20 [?H] to 50 [?H].

Abstract: A mounting structure for mounting inductors to suppress cross talk and a stub effect due to a mounting land, and reduce deterioration of signal transmission characteristics. A first Bias-T inductor is mounted on a circuit board with one electrode terminal connected to a first mounting land with an axial direction of the first Bias-T inductor oriented perpendicular to the first mounting land and the one electrode terminal extends along the first mounting land. A second Bias-T inductor is mounted on the circuit board in the vicinity of the first Bias-T inductor with one electrode terminal connected to a second mounting land with an axial direction of the second Bias-T inductor inclined by 90° with respect to the axial direction of the first Bias-T inductor and the second Bias-T inductor is oriented perpendicular to the second mounting land and the one electrode terminal extends along the second mounting land.

Abstract: An electronic circuit includes a shield line including first and second signal lines and a shield. The first and second signal lines are connected to a signal source, and the shield coating is around the first and second signal lines. The electronic circuit further includes a signal ground near the signal source; a frame ground that is isolated from the signal ground and connected to the shield; a common mode choke coil that includes first, second and third coils magnetically coupled to one another; and a capacitor that is connected in parallel with the third coil. The first coil is connected in series between the signal source and the first signal line. The second coil is connected in series between the signal source and the second signal line. The third coil and the capacitor that are connected in parallel are connected between the signal ground and the frame ground.

Abstract: A circuit module includes a wiring board on which are provided a ground plane, a signal line, and a conductive pattern for connection to an outer conductor of a coaxial cable including an inner conductor and the outer conductor. A common-mode choke coil is mounted on the wiring board such that one of coils of the common-mode choke coil connects the ground plane and the conductive pattern and that the other coil is inserted in the signal line. A communication element is mounted on the wiring board and includes a first signal terminal and a second signal terminal. The first signal terminal is connected to the common-mode choke coil via the signal line, and the second signal terminal is connected to the ground plane. A first capacitor is inserted in series in the signal line between the common-mode choke coil and the first signal terminal.

Abstract: A circuit module includes a wiring board on which are provided a ground plane, a signal line, and a conductive pattern for connection to an outer conductor of a coaxial cable including an inner conductor and the outer conductor. A common-mode choke coil is mounted on the wiring board such that one of coils of the common-mode choke coil connects the ground plane and the conductive pattern and that the other coil is inserted in the signal line. A communication element is mounted on the wiring board and includes a first signal terminal and a second signal terminal. The first signal terminal is connected to the common-mode choke coil via the signal line, and the second signal terminal is connected to the ground plane. A first capacitor is inserted in series in the signal line between the common-mode choke coil and the first signal terminal.