Abstract: In a digital receiver, a noise attenuation and signal magnitude mapping variable amplifying unit includes a filter and an amplifier, amplifies and band-bass filters an analog signal and attenuating white noise and an interference signal other than a band signal. An ADC performs sub sampling on a carrier frequency of a desired signal and performs oversampling on the band of the desired signal by using a sampling frequency to convert the analog signal which has passed through the noise attenuation and signal magnitude mapping variable amplifying unit into a digital signal of a direct conversion frequency band or an intermediate frequency band. The ADC has a dynamic range for processing both the desired signal and an undesired signal adjacent to the desired signal. A digital signal processing unit converts a signal frequency of the digital signal or digital-filters an undesired signal within the digital signal and processes the digital signal by digitally adjusting a gain.

Abstract: Provided is a wireless transceiving apparatus for variability of signal processing band, in which at least one resonator of an analog processor and a VCO are simultaneously controlled using a frequency synthesizer, and a frequency of the VCO and a resonance frequency of the analog processor are controlled to have a rational number ratio, thereby capable of varying the signal processing band. The wireless transceiving apparatus includes: an analog processor having a plurality of resonators on a path of transmission/reception signals, for performing analog signal processing; a digital processor for performing digital signal processing on an output signal of the analog processor or data to be transmitted to the analog processor; and a frequency synthesizer for providing a local oscillation (LO) frequency and a controlling signal to the resonators of the analog processor so as to vary a signal processing band of the analog processor.

Abstract: A digital-intensive RF receiver including: a first filter unit configured to allow an RF signal of a pre-set frequency band among RF signals to pass therethrough; a low noise amplifier (LNA) configured to amplify the RF signal from the first filter unit such that the RF signal has a pre-set magnitude; a second filter unit configured to allow an RF signal of a pre-set frequency band among RF signals from the LNA to pass therethrough; a clock generation unit configured to generate a pre-set reference frequency signal and generate a sub-sampling clock having a pre-set frequency lower than an RF carrier frequency by using the reference frequency signal; a sub-sampling A/D conversion unit configured to A/D-convert the RF signal from the second filter unit into a digital signal according to the sub-sampling clock from the clock generation unit, divide the RF signal into a plurality of frequency bands and sub-sample them during the A/D conversion process and perform noise shaping by the sub-channels included in the

Abstract: Provided is an apparatus having a variable capacitor circuit which is capable of obtaining a constant gain with respect to a whole control voltage by using a linear variable frequency characteristic for a variation of the control voltages, to thereby attain a wide variable frequency range. For this, a variable capacitor circuit includes a plurality of variable capacitors being connected in parallel with each other and having different capacitances with respect to an input control voltage, wherein the sum of the variable capacitances of the plurality of variable capacitors at a same voltage level of the control voltage varied within the whole control voltage range has linearity.

Abstract: A wideband low-noise amplifier includes a source-degenerated common-source amplifier, a common-gate amplifier, and a matching frequency band determiner. The source-degenerated common-source amplifier is configured to amplify an input signal to output a first signal that is opposite in phase to the input signal. The common-gate amplifier is connected in parallel to the source-degenerated common-source amplifier to amplify the input signal to output a second signal that has the same phase as the input signal. The matching frequency band determiner is configured to isolate an input terminal of the source-degenerated common-source amplifier and an input terminal of the common-gate amplifier and determine a matching frequency band.

Abstract: Provided are a voltage controlled digital analog oscillator and a frequency synthesizer using the same, the oscillator comprising an oscillator having a frequency of an output signal being determined by a voltage inputted to an analog input end and a digital value inputted to a digital input end; and a digital tuner for comparing the voltage inputted to the analog input end to first and second threshold voltages and changing the digital value inputted to the digital input end according to the result, whereby it is possible to obtain a broadband frequency output with less noise.

Abstract: A complementary metal oxide semiconductor (CMOS) variable gain amplifier has a wider decibel-linear gain variation characteristic with respect to a control voltage when a signal is amplified. The variable gain amplifier includes: a bias input circuit for supplying a current corresponding to a bias voltage; an operation region combination and feedback circuit connected to the bias input circuit and combining at least two amplifiers by feedback in response to a control voltage, each amplifier having a decibel-linear characteristic in saturation and triode regions of a complementary metal oxide semiconductor (CMOS); and a bias output circuit connected to the bias input circuit, and outputting bias current controlled by the operation region combination and feedback circuit.

Abstract: Provided is an apparatus having a variable capacitor circuit which is capable of obtaining a constant gain with respect to a whole control voltage by using a linear variable frequency characteristic for a variation of the control voltages, to thereby attain a wide variable frequency range. For this, a variable capacitor circuit includes a plurality of variable capacitors being connected in parallel with each other and having different capacitances with respect to an input control voltage, wherein the sum of the variable capacitances of the plurality of variable capacitors at a same voltage level of the control voltage varied within the whole control voltage range has linearity.

Abstract: Provided is a low noise amplifier with a common source and a source degeneration, which has linearity, power gain, noise factor, and lossless input matching. The low noise amplifier includes: a first inductor having one terminal connected to an input terminal receiving a signal; a second inductor having one terminal connected to a ground; a MOS transistor having a gate connected to the first inductor, a source connected to the other terminal of the second inductor, and a drain transmitting a signal; and a variable capacitor connected between the source and gate of the MOS transistor and varying an input matching frequency at the input terminal.

Abstract: Provided are a linearized variable-capacitance module for a voltage-controlled oscillator (VCO) and an LC resonance circuit using the same. The VCO is a circuit for outputting a certain frequency in response to an input control signal (voltage or current). The VCO includes an inductor, a variable capacitor (or a varactor), and an active device for compensating for loss of energy caused by the inductor and varactor. The frequency of the VCO is varied by changing inductance or capacitance. In general, the VCO includes a variable-capacitance device (i.e., the varactor) so that the frequency of the VCO may be varies by changing the capacitance via a control voltage. In most cases, the frequency of the VCO varies nonlinearly with respect to the control voltage. The nonlinear variation in the frequency of the VCO results in a great variation in a VCO gain within a certain control voltage range.

Abstract: A complementary metal oxide semiconductor (CMOS) variable gain amplifier has a wider decibel-linear gain variation characteristic with respect to a control voltage when a signal is amplified. The variable gain amplifier includes: a bias input circuit for supplying a current corresponding to a bias voltage; an operation region combination and feedback circuit connected to the bias input circuit and combining at least two amplifiers by feedback in response to a control voltage, each amplifier having a decibel-linear characteristic in saturation and triode regions of a complementary metal oxide semiconductor (CMOS); and a bias output circuit connected to the bias input circuit, and outputting bias current controlled by the operation region combination and feedback circuit.

Abstract: Provided are a voltage controlled digital analog oscillator and a frequency synthesizer using the same, the oscillator comprising an oscillator having a frequency of an output signal being determined by a voltage inputted to an analog input end and a digital value inputted to a digital input end; and a digital tuner for comparing the voltage inputted to the analog input end to first and second threshold voltages and changing the digital value inputted to the digital input end according to the result, whereby it is possible to obtain a broadband frequency output with less noise.

Abstract: Provided is a wireless transceiving apparatus for variability of signal processing band, in which at least one resonator of an analog processor and a VCO are simultaneously controlled using a frequency synthesizer, and a frequency of the VCO and a resonance frequency of the analog processor are controlled to have a rational number ratio, thereby capable of varying the signal processing band. The wireless transceiving apparatus includes: an analog processor having a plurality of resonators on a path of transmission/reception signals, for performing analog signal processing; a digital processor for performing digital signal processing on an output signal of the analog processor or data to be transmitted to the analog processor; and a frequency synthesizer for providing a local oscillation (LO) frequency and a controlling signal to the resonators of the analog processor so as to vary a signal processing band of the analog processor.

Abstract: Provided is a low noise amplifier with a common source and a source degeneration, which has linearity, power gain, noise factor, and lossless input matching. The low noise amplifier includes: a first inductor having one terminal connected to an input terminal receiving a signal; a second inductor having one terminal connected to a ground; a MOS transistor having a gate connected to the first inductor, a source connected to the other terminal of the second inductor, and a drain transmitting a signal; and a variable capacitor connected between the source and gate of the MOS transistor and varying an input matching frequency at the input terminal.

Abstract: The present invention relates to a structure of a delta-sigma fractional type divider. The divider structure adds an external input value and an output value of a delta-sigma modulator to modulate a value of a swallow counter. Therefore, the present invention can provide a delta-sigma fractional type divider the structure is simple and that can obtain an effect of a structure of a delta sigma mode while having a wide-band frequency mixing capability.

Abstract: The present invention relates to a ROM division method for reducing the size of a ROM in a direct digital frequency synthesizer (DDFS), which is used to synthesize a frequency in a communication system requiring fast frequency conversion. A ROM consuming most energy in the system, a modified Nicholas architecture is brought forth to reduce the size of ROM. In this modified Nicholas architecture, a ROM is divided into coarse ROM and fine ROM to convert phase to sine value. The present invention divides the coarse ROM and the fine ROM into quantized ROM and error ROM respectively. Then, value stored in each ROM is segmented in certain intervals and the minimum quantized value in each of the section is stored in the quantized ROM, while the difference between the original ROM value and the quantized ROM value is stored in the error ROM. This way, the size of a ROM can be reduced. Phase value inputted in a DDFS, a sine value is calculated by adding the four ROM values, i.e.

Abstract: An automatically gain controllable linear differential amplifier using a variable degeneration resistor is disclosed. The linear differential amplifier includes an input end, a bias current source, a load unit, a first MOS transistor and a second MOS transistor. The linear differential amplifiers of the present invention can control an amplifying gain according to an input signal and improve linearity IIP3 without needing additional power consumption caused by improving the linearity. The automatically gain controllable linear differential amplifier uses NMOS/PMOS transistor so an integration process of the amplifier can be implemented more conveniently and efficiently.

Abstract: The present invention relates to a structure of a delta-sigma factional divider. The divider structure adds an external input value and an output value of a delta-sigma modulator to modulate a value of a swallow counter. Therefore, the present invention can provide a delta-sigma factional divider the structure is simple and that can obtain an effect of a delta sigma mode while having a wide-band frequency mixing capability.

Abstract: An automatically gain controllable linear differential amplifier using a variable degeneration resistor is disclosed. The linear differential amplifier includes an input end, a bias current source, a load unit, a first MOS transistor and a second MOS transistor. The linear differential amplifiers of the present invention can control an amplifying gain according to an input signal and improve linearity IIP3 without needing additional power consumption caused by improving the linearity The automatically gain controllable linear differential amplifier uses NMOS/PMOS transistor so an integration process of the amplifier can be implemented more conveniently and efficiently.

Abstract: The present invention relates to a structure of a delta-sigma fractional type divider. The divider structure adds an external input value and an output value of a delta-sigma modulator to modulate a value of a swallow counter. Therefore, the present invention can provide a delta-sigma fractional type divider the structure is simple and that can obtain an effect of a structure of a delta sigma mode while having a wide-band frequency mixing capability.