Patent application number | Description | Published |
20090233435 | SEMICONDUCTOR DEVICES AND MANUFACTURING METHOD THEREOF - A method is set forth of forming an ohmic electrode having good characteristics on a SiC semiconductor layer. In the method, a Ti-layer and an Al-layer are formed on a surface of the SiC substrate. The SiC substrate having the Ti-layer and the Al-layer is maintained at a temperature that is higher than or equal to a first temperature and lower than a second temperature until all Ti in the Ti-layer has reacted with Al. The first temperature is the minimum temperature of a temperature zone at which the Ti reacts with the Al to form Al | 09-17-2009 |
20090289723 | PLL OSCILLATION CIRCUIT, POLAR TRANSMITTING CIRCUIT, AND COMMUNICATION DEVICE - Provided is a PLL oscillation circuit that can reduce the variability of modulation sensitivity of a VCO | 11-26-2009 |
20100102332 | METHOD OF FORMING AN OHMIC CONTACT ON A P-TYPE 4H-SIC SUBSTRATE - A method of forming an Ohmic contact on a P-type 4H—SiC and an Ohmic contact formed by the same are provided. A method of forming an Ohmic contact on a P-type 4H—SiC substrate including a deposition step of successively depositing a 1 to 60 nm thick first Al layer, Ti layer, and second Al layer on a P-type 4H—SiC substrate and an alloying step of forming an alloy layer between the SiC substrate and the Ti layer through the first Al layer by heat treatment in a nonoxidizing atmosphere. An Ohmic contact on a P-type 4H—SiC substrate formed by this method is also provided. | 04-29-2010 |
20120013409 | DIGITAL FREQUENCY/PHASE LOCKED LOOP - A digital FLL/PLL is provided which is capable of converging an oscillation frequency from a VCO to a desired frequency at a high speed even without setting a damping factor corresponding to each VCO gain. A digital FLL/PLL of the present invention includes: a comparator for comparing a channel signal to a loopback signal having an oscillation frequency to generate a signal error; a digital loop filter for generating a control voltage that determines the oscillation frequency, on the basis of the signal error; a VCO for controlling an oscillation frequency on the basis of the control voltage; a loopback path through which the oscillation frequency generated by the VCO is outputted as the loopback signal to the comparator; and a control section for monitoring the signal error, and controlling the digital loop filter such that the oscillation frequency of the VCO becomes a stationary state, when detecting that the signal error meets a predetermined condition after the channel signal is switched. | 01-19-2012 |
20120058804 | CMOS-INVERTER-TYPE FREQUENCY DIVIDER CIRCUIT, AND MOBILE PHONE INCLUDING THE CMOS-INVERTER-TYPE FREQUENCY DIVIDER CIRCUIT - The present invention provides a CMOS-inverter-type frequency divider circuit that can further reduce power consumption. | 03-08-2012 |
20120094712 | AMPLITUDE MODULATOR - An amplitude modulator comprises: a signal processing section for receiving a source signal for wide bandwidth use, splitting the source signal into two source signals for lower frequency use and for higher frequency use, respectively, signal processing the two source signals individually, and outputting a lower-frequency-use source signal and a higher-frequency-use source signal;
| 04-19-2012 |
20120105111 | TRANSMITTER INCLUDING POLAR MODULATION CIRCUIT - Provided is a transmitter including a polar modulation circuit which adjusts a timing lag between an amplitude component and a phase component more accurately than a conventional art. The polar modulation circuit includes: an extraction section for extracting an amplitude component and a phase component from an input signal; a first processing section for performing a first signal process on the amplitude component; a second processing section for performing a second signal processing on the phase component; an amplifier for synthesizing an output of the first processing section and an output of the second processing section and amplifying the synthesized outputs; a first calculator for performing an exclusive OR logical operation between the amplitude component before being inputted to the first processing section and the amplitude component after having been inputted to the first processing section; a first accumulation section for accumulating outputs of the first calculator; a second calculator for performing an exclusive OR logical operation between the phase component before being inputted to the second processing section and the phase component after having been inputted to the second processing section; a second accumulation section for accumulating outputs of the second calculator; and a delay fluctuation detection/compensation section for obtaining a delay time of the amplitude component based on an amount of accumulation of the first accumulation section; obtaining a delay time of the phase component based on an amount of accumulation of the second accumulation section; detecting an amount of delay fluctuation by using the delay times; and adjusting timings of the amplitude component and the phase component. | 05-03-2012 |
20150180418 | TRANSMITTING APPARATUS AND TRANSMISSION METHOD - A transmitting apparatus and transmission method are capable of easily and correctly mixing an in-phase component and a quadrature-phase component in a quadrature modulator. A local signal with a duty ratio of 25% or smaller is generated without using frequency which is a multiple of frequency of the local signal. Without providing switches in series to the outputs of I and Q amplifiers, a duty ratio of 25% or less is obtained. for the local signal, and class-D unit amplifiers are operated such that one of the I amplifier and the Q amplifier is connected to the output side in any state regardless of whether an output power control signal is at an on-level or an off-level. In producing the 25% duty ratio, a local signal with a 50% duty ratio is converted so as to have a duty ratio of 25% by I and Q duty converters. | 06-25-2015 |