Abstract: A booting access method and a storage device of an embedded system are provided. The booting access method of the embedded system is applied to the storage device which includes a master boot record (MBR) section, a hidden section and a public section to improve access precision of embedded memory data. The access method includes: using the MBR section to access data of the public section when a normal booting signal is received; using a boot loader in the hidden section to update the MBR section and then accessing data of the public section when a trigger update signal is received.

Abstract: A positive differential signal trace and a negative differential signal trace are formed on different layers of a printed circuit board. A first ground trace is formed on the layer on which the positive differential signal trace is formed, and a second ground trace is formed on the layer on which the negative differential signal trace is formed. An insulation layer is positioned between the two layers and has a predetermined thickness. A differential mode impedance and a common mode impedance of differential signals are dependent on the predetermined thickness of the insulation layer, width and thickness of each differential signal trace, and a space between each differential signal trace and the corresponding ground trace formed on the same layer.

Abstract: A positive differential signal trace and a negative differential signal trace are formed on different layers of a printed circuit board. A first ground trace is formed on the layer on which the positive differential signal trace is formed, and a second ground trace is formed on the layer on which the negative differential signal trace is formed. An insulation layer is positioned between the two layers and has a predetermined thickness. A differential mode impedance and a common mode impedance of differential signals are dependent on the predetermined thickness of the insulation layer, width and thickness of each differential signal trace, and a space between each differential signal trace and the corresponding ground trace formed on the same layer.

Abstract: A video transmission apparatus and the connector module thereof are provided. The connector module includes a first resistor and a second resistor. The first resistor is coupled between a voltage source and a transmission pin. The second resistor is coupled between a ground terminal and a connector. When the transmission pin is in a floating state, the transmission pin outputs a floating voltage. And when the connector is coupled to the transmission pin, the transmission pin outputs a connection voltage. According to the DC voltage output by the transmission pin, the connector module judges the coupling state between the connector and the transmission pin.

Abstract: The present invention provides an anti-pop circuit composed of a capacitor and a switch. A control signal is used to switch the switch to make the capacitor grounded. The grounded capacitor may shunt the “pop” sound at the moment the power (Vcc) is turned on or off.

Abstract: A presser foot for sewing machines including a body portion formed with a recess at a lower end thereof and a threaded hole above the recess, a knob having a cylindrical member having a large diameter at a first end and a small diameter at a second end, the knob being formed with a concaved portion between the ends and an axial through hole with a counter sink at the first end, the knob being rotatably mounted on the body portion by a countersunk bolt which extends through the axial through hole into the threaded hole thereby forming a generally semi-circular cavity, whereby the feeding of a workpiece through the presser foot can be facilitated.