Abstract: An automatic gain control apparatus, employed in a communication system having a circuit that interfaces a two-wire line to a four-wire line, measures the echo return loss occurring at the interface, calculates a gain from the echo return loss, and amplifies an incoming signal on the four-wire line by the calculated gain before transmission through the interface, to compensate for the echo return loss. If the communication system uses an echo canceler to cancel the echo, the echo canceler is preferably shielded from the effects of automatic gain control, by attenuation of the outgoing signal on the four-wire line, for example.

Abstract: A method for detecting a tone signal includes determining a correlative value of an input signal obtained for each frame of a predetermined length, determining an estimating expression that represents an output power of a second order FIR band elimination filter that uses the correlative value of the input signal as an input and a frequency thereof as a parameter, determining a frequency at which a minimum value of the estimating expression is obtained, determining a prediction gain of the FIR band elimination filter at the determined frequency, and determining that the input signal is a tone signal if a value of the determined prediction gain exceeds a preset threshold value.

Abstract: A ferroelectric memory of the present invention comprises a memory cell which includes a select transistor whose control electrode, first electrode and second electrode are respectively connected to a word line, a bit line and a first node, a ferroelectric capacitor whose first electrode and second electrode are respectively connected to the first node and connected to a plate line through a second node, and a resistor connected between the first node and the second node.

Abstract: A carriage for a linear guiding device, designed to be arranged on a rail. The carriage includes a center section and two legs that each join the center section, thus providing the carriage with an essentially U-shaped design. The carriage further includes a support region as well as two deflector channels that connect the return channel and the support region, sleeve-shaped guiding elements that are arranged in recesses of a basic body of the carriage, in the return channels. Plastic material is poured in part or totally around one of the two ends of at least one sleeve-shaped guiding elements in order to secure it inside the recess. The sleeve-shaped guiding elements are each provided with centering elements on their outside surfaces, which elements are used to determine the position of a guiding element.

Abstract: A slot array antenna includes a feed waveguide plate, a radiating waveguide plate and a slot plate adhered or connected together. The feed waveguide plate is formed with a first feed port and a feed waveguide to which an electromagnetic wave is fed via the feed port. The radiating waveguide plate is formed with second feed ports communicated to the feed waveguide, and radiating waveguides communicated to the second feed ports. The slot plate is formed with slots for radiating electromagnetic waves fed via the radiating waveguides. The first feed port is positioned substantially at the center of the length of the feed waveguide. The slot array antenna allows a polarization direction of the antenna to be freely adjusted while minimizing a wasteful space otherwise allotted to peripheral circuits and is therefore miniaturized.