Abstract: A signal transmission apparatus includes two circuit layers. First and second ground sheets are arranged in the two circuit layers respectively. A third ground sheet is arranged between the two circuit layers. A differential pair includes a transmission line arranged between the first and third ground sheets and a transmission line arranged between the second and third ground sheets. The first to third ground sheets have same electric potential. Projections of the first and second ground sheets on the third ground sheet superpose a border of the third ground sheet. The third ground sheet is formed by extending the border along a signal transmission direction. A vertical distance between the first and second transmission lines is twice as each of a vertical distance from the first ground sheet to the first transmission line and a vertical distance from the second ground sheet to the second transmission line.

Abstract: A printed circuit board includes a layer. A layer of copper is covered on a surface of the layer. A through hole passes through the printed circuit board. An approximately C-shaped thermal engraving is defined in the surface of the layers, surrounding the through hole and without being covered by the layer of copper. An opening of the thermal engraving faces an output terminal of the power supply.

Abstract: An enclosure of an electronic device includes a plate. The plate defines a number of through holes. Each through hole has a pair of tabs connected to each other and with the through hole. Each pair of tabs are slantingly bent towards an inside of the enclosure. The enclosure with the shields can shield the electronic device from electro-magnetic interference.

Abstract: An exemplary antistatic device includes an electricity receiving part and an electricity discharging part. Guiding portions protrude from the electricity receiving part. The electricity discharging part is located at a side of the electricity receiving part, and oriented toward and spaced from the guiding portions of the electricity receiving part. The electricity discharging part is electrically conductive and capable of being grounded. Static electricity accumulated on the electricity receiving part is removable to the electricity discharging part via the guiding portions.

Abstract: An enclosure includes a plate. The plate defines a number of through holes. A hollow shield extends from the edges bounding each through hole. A top side of the shield opposite to the plate is smaller than a bottom side of the shield which is connected to the edges of the through hole. The enclosure can better shield electromagnetic interference (EMI) from the electronic device.

Abstract: A printed circuit board includes a signal layer and a ground layer adjacent to the signal layer. The signal layer includes a pair of differential transmitting lines. The ground layer includes a common mode filter formed by hollow spiral patterns in the ground layer. The common mode filter includes two filter portions respectively arranged at opposite sides of a projection of the pair of differential transmitting lines onto the ground layer. Hollowed areas of the two filter portions are bridged by a void.

Abstract: An exemplary high speed data storage system includes hard disks, a first control panel, a second control panel and a midplane interconnected between each of the first and second control panels and the hard disks. Each of the first and second control panels includes a control chip and a connector. First and second printed circuit wires corresponding to the hard disks are layered on the first and second control panels for electrically connecting the control chip with the connector, respectively. The first printed circuit wires of the first control panel and the second printed circuit wires of the second control panel are arranged symmetrically with respect to each other, and an order of stacking circuit layers of the first printed circuit wires of the first control panel is the reverse of an order of stacking of circuit layers of the second printed circuit wires of the second control panel.

Abstract: A printed circuit board includes a number of signal layers, a number of ground layers, a first transmission line, a second transmission line, a first via, and a second via. The first transmission is located on one of the number of signal layers. The second transmission line is located on another of the number of signal layers. The first and second vias pass through the printed circuit board. The first via is electrically coupled to the first and second transmission lines, and is isolated from the number of ground layers. The second via is electrically coupled to one or more of the number of ground layers, and is isolated from the other of the number of ground layers to increase an inductance, thus compensating capacitive nature of an open stub and improving signal integrity.

Abstract: A printed circuit board includes a first signal layer, a second signal layer, and a dielectric layer sandwiched between the first signal layer and the second signal layer. The first signal layer includes two pads. The second signal layer includes two conducting pieces connected to two signal traces. The shape and material of the pads are the same as the shape and material of the conducting pieces. The projections of the pads on the second signal layer are overlapping with the conducting pieces.

Abstract: A printed circuit board includes a signal layer and a ground layer adjacent to the signal layer. The signal layer includes a pair of differential transmission lines. The ground layer includes a first void, a second void, a third void, and a common mode filter. The first void and the second void are respectively arranged at opposite sides of a projection of the pair of differential transmission lines on the ground layer, and are bridged with the third void. The common mode filter includes a first filter portion positioned in the first void, and a second filter portion positioned in the second void. Each of the first and second filter portions includes a number of coils arranged side by side along a direction parallel to the projection of the pair of differential transmission lines.

Abstract: An enclosure includes a plate. The plate defines a number of through holes. A first shield extends from an edge bounding each through hole. A second shield extends from the edge bounding each through hole, opposite to the first shields. Each through hole is partially covered by a corresponding first shield and a corresponding second shield. The enclosure with the shields can shield the electronic device from electromagnetic interference.

Abstract: A method of testing a printed circuit board (PCB) acquires test points from a wiring diagram of the PCB. Frequency domain tested items for each test point and a standard value of each frequency domain tested item are preset. A distance between a preset fiducial point and each test point is computed to create a testing order of the test points according to the distances. The frequency domain tested items of each test point are computed according to the testing order. A pass or a failure of each test point is displayed according to a determination of if each of the computed frequency domain tested items within the corresponding standard value, and a test result of the PCB is output according to the passes or the failures.

Abstract: A motherboard includes a printed circuit board (PCB) and a memory connector. A number of golden fingers are set on corresponding sides of a top layer and a bottom layer of the PCB and connected to a memory controller. First and second socket slots are defined in two opposite sides of the memory connector. A number of grooves are defined in top and bottom sidewalls bounding the first and the second socket slots. A number of metal pins are exposed through the grooves of the first socket slot for connection to the golden fingers of the PCB. The metal pins are extended to the second socket slot to be exposed through the grooves of the second socket opening for connection to the golden fingers of a memory.

Abstract: A motherboard includes a printed circuit board (PCB) and a memory connector. The PCB includes top and bottom layers. A number of pads are set on the sides of the top and bottom layers and connected to a memory controller. A number of metal pins are set on a first sidewall of the memory connector. A socket slot is defined in a second sidewall opposite to the first sidewall. Top and bottom sidewalls bounding the socket slot define a number of grooves. First ends of the metal pins are soldered on the pads of the top layer and the bottom layer of the PCB. Second ends of the metal pins are extended to the socket slot through the memory connector and exposed through the grooves of the memory connector, to be electrically connected to the golden fingers of a memory when the memory is inserted in the socket slot.

Abstract: A printed circuit board (PCB) includes a top layer, a memory controller, a gap, and a connector. The memory controller is located on the top layer. A number of first golden fingers are set on the top layer near the gap and electrically connected to the memory controller. A connector includes a first slot to hold the first golden fingers and a second slot to hold a number of second golden fingers of a memory chip. The first slot is electrically connected to the second slot. The memory chip and the PCB are coplanar.

Abstract: A printed circuit board includes a first layout layer, a second layout layer, a copper foil layer, a first via and a second via. The first layout layer has a first signal line and a second signal line, each of which has a curved first portion. The second layout layer has a third signal line and a fourth signal line, each of which also has a curved first portion. The curved first portions of the first signal line, the second signal line, the third signal line and the fourth signal line are coupled to the first via and the second via. In this case, the curved first portions of the first signal line, the second signal line, the third signal line and the fourth signal line cooperatively generate spiral inductance characteristic.

Abstract: A computing device and a method for scattering parameter equivalent circuit reads a scattering parameter file from a storage device. A non-common-pole rational function of the scattering parameters in the scattering parameter file is created by applying a vector fitting algorithm to the scattering parameters. Passivity of the non-common-pole rational function is enforced if the non-common-pole rational function does not satisfy a determined passivity requirement.

Abstract: A printed circuit board includes a layer. A layer of copper is covered on a surface of the layer. A through hole extends through the printed circuit board. A thermal engraving is defined in the surface of the layer, surrounding the through hole and without being covered by the layer of copper. The thermal engraving includes a first opening and a second opening. The first opening of the thermal engraving faces an output terminal of the power supply, and is non-contiguous with the second opening.

Abstract: A method for modulating multiple-instruments and multiple-sensors using an electronic device. The electronic device controls an instrument to measure the working parameters of an object, and controls a sensor to detect the working temperature of the object. By comparing the working parameters against a predefined range, and comparing the working temperature against a predefined temperature value, the electronic device determines whether the instrument and the sensor need to be modulated. If any of the working parameters is not within the predefined range or if the working temperature is greater than the predefined temperature value, the electronic device controls the instrument and the sensor to be modulated by using a modulation transfer function and a predetermined direction.

Abstract: A handheld input device includes a main body. The main body includes a first sidewall, a second sidewall, and a touch pad. The first sidewall is arc shaped and includes function buttons. The second sidewall is substantially perpendicular to the first sidewall. The touch pad is positioned on one end of the main body.