Abstract:
The retractable cable device includes a base, a rotary portion, a spring, a cover, and at least two medal plates. The rotary portion cooperates with the base to form a cavity, and the cable is disposed on the rotary portion. The spring is disposed in the cavity for driving the rotary portion to rotate. The cover is coupled to the base. The metal plate is connected to the rotary portion for maintaining an electrical connection between the antenna and the cable when the rotary portion rotates.
Abstract:
A system includes a plurality of modules which are configured for determining a suitable impedance for a modem. The plurality of modules send signals with a plurality of signal frequencies to a telephone and receive feedback signals from the telephone under each of a plurality of impedances of the modem, compute a total decibel value of the feedbacks under each impedance, and determine a suitable impedance according to a minimum total decibel value from the plurality of total decibel values.
Abstract:
A modem (10) includes a signal tuner module (101), a signal processing module (103), and a mode switching module (105). The signal tuner module receives a radio frequency (RF) signal in a first operation mode, and converts the RF signal to an intermediate frequency (IF) signal according to the first operation mode. The signal processing module processes the IF signal to generate an error rate according to the first operation mode. The mode switching module determines whether the first operation mode is right according to the error rate, and switches from the first operation mode to a second operation mode when the first operation mode is not right. A method for switching operation modes thereof is also provided.