Abstract: A tuning amplifier 1 is provided with an oscillation circuit 10 incorporating an amplifier circuit 11 and a feedback circuit 12, an input circuit 14 which inputs signals to the oscillation circuit 10, and an automatic gain control (AGC) circuit 16 which controls the output amplitude of the oscillation circuit 10. When signals are inputted to the oscillation circuit 10 through the input circuit 14, such tuning that only signals having frequencies near the oscillation frequency of the oscillation circuit 10 are allowed to pass through is possible.

Abstract: An LC element, semiconductor device and a manufacturing method thereof whereby a channel 22 is formed by applying a voltage to a gate electrode 10 having a predetermined shape formed on a p-Si substrate 30 via an insulation layer 26, whereby a connection is formed between a first diffusion region 12 and a second diffusion region 14 formed at separated positions near the surface of the p-Si substrate 30; both the channel 22 gate electrode 10 function as inductors, and between these a distributed constant type capacitor is formed, and possessing excellent attenuation characteristics over a wide band. This LC element and semiconductor device can be easily manufactured by using MOS manufacturing technology; in the case of manufacturing as a portion of a semiconductor substrate, component assembly work in subsequent processing can be omitted. Also these can be formed as a portion of an IC or LSI device.

Abstract: An LC element for use with a semiconductor device features excellent attenuation characteristics. The element includes a pn junction that has a predetermined shape and which is formed near the surface of a semiconductor substrate. The predetermined shapes include a spiral shape, a meander shape, a straight shape, and a curved shape. An inductor electrode is formed on the pn junction, and the pn junction is reverse biased with a specified voltage to form a distributed capacitor having a desired capacitance. One of the p and n layers functions as an inductor. The element is easily manufactured and requires minimal assembly, and may also be integrally formed as part of an IC or LSI device.

Abstract: An LC element, semiconductor device and a manufacturing method thereof whereby a channel 22 is formed by applying a voltage to a gate electrode 10 having a predetermined shape formed on a p-Si substrate 30 via an insulation layer 26, whereby a connection is formed between a first diffusion region 12 and a second diffusion region 14 formed at separated positions near the surface of the p-Si substrate 30; both the channel 22 and gate electrode 10 function as inductors, and between these a distributed constant type capacitor is formed, and possessing excellent attenuation characteristics over a wide band. This LC element and semiconductor device can be easily manufactured by using MOS manufacturing technology; in the case of manufacturing as a portion of a semiconductor substrate, component assembly work in subsequent processing can be omitted. Also these can be formed as a portion of an IC or LSI device.