Abstract: A light source device includes a solid light emitting element 1 having a reflection film on the back side, first and second reflection surfaces 2, 3 opposing each other in parallel and substantially perpendicular to a front surface of the solid light emitting element 1 and a third reflection surface 4 substantially perpendicular to the first and second reflection surfaces 2, 3 and opposing the front surface of the solid light emitting element 1. The third reflection surface 4 is inclined to the front surface of the solid light emitting element 1. The reflection film of the element 1, the first, second and third reflection surfaces 2, 3, 4 do constitute a closed polyhedron having an emission opening 5 smaller than a light emitting surface of the element 1. Light emitted from the element 1 is emitted to an outside through the emission opening 5.

Abstract: A semiconductor device comprises a DSP (Digital Signal Processor), a CPU for controlling the DSP and an interface circuit. The interface circuit comprises an input circuit, a gain-adjusting circuit and an output circuit. The input circuit inputs a digital signal and supplies the signal to the DSP synchronously with a first clock signal. The gain-adjusting circuit is capable of adjusting the gain of the digital signal supplied to the input circuit. The output circuit adds a digital signal received from the DSP to the digital signal with the gain thereof adjusted and outputs a signal obtained as a result of the addition synchronously with the first clock signal. A signal path extended from the input circuit through the gain-adjusting circuit to the output circuit forms hardware. A digital signal to be transmitted propagates through the hardware to be subjected to the so-called side-tone processing.

Abstract: A semiconductor device comprises a DSP (Digital Signal Processor), a CPU for controlling the DSP and an interface circuit. The interface circuit comprises an input circuit, a gain-adjusting circuit and an output circuit. The input circuit inputs a digital signal and supplies the signal to the DSP synchronously with a first clock signal. The gain-adjusting circuit is capable of adjusting the gain of the digital signal supplied to the input circuit. The output circuit adds a digital signal received from the DSP to the digital signal with the gain thereof adjusted and outputs a signal obtained as a result of the addition synchronously with the first clock signal. A signal path extended from the input circuit through the gain-adjusting circuit to the output circuit forms hardware. A digital signal to be transmitted propagates through the hardware to be subjected to the so-called side-tone processing.