Abstract: An apparatus and a method for increasing Error Vector Magnitude (EVM) performance representing quality of transmission signal are provided. The apparatus and the method suppress an image frequency component generated due to mismatch of IQ channels in order to transmit/receive a large amount of data without distortion in 4th generation wireless communication standard candidate technologies such as a Long Term Evolution (LTE) system and a mobile WiMax system. The apparatus includes a LOcal frequency (LO) buffer including an amplifier. The LO buffer controls the gain and the phase of the amplifier using a control bit for controlling resistor connection.

Abstract: A low-noise amplification apparatus and method in a receiver in a wireless communication system are provided, in which a main amplifier amplifies a received signal, a sub-amplifier amplifies a third-order harmonic component more strongly than a signal component in the received signal and cancels the third-order harmonic component by combining the amplified signal with the signal received from the main amplifier. A noise eliminator amplifies noise included in the received signal and eliminates the noise by combining the amplified noise with the signal received from the main amplifier or the signal received from the sub-amplifier.

Abstract: An apparatus and method for frequency synthesis using a Delay Locked Loop (DLL) are provided. The apparatus includes the DLL, an edge pulse generator, and an inductive-capacitive (LC) tank switch. If phases of a reference frequency signal and a feedback signal are the same and thus are locked, the DLL delays the reference frequency signal. The edge pulse generator generates a plurality of pulse signals representing phase delay amounts of signals. The LC tank switch combines the plurality of pulse signals and generates frequency.

Abstract: Provided are a receiving circuit including a balun circuit and a notch filter, and an operating method thereof. The receiving circuit includes a transformer, a notch filter, and a mixer. The transformer converts a single input signal to a differential input signal using a first tap. The notch filter blocks a specific frequency band of the single input signal by connecting a second tap with the first tap of the transformer using a condenser.

Abstract: An apparatus and a method for increasing Error Vector Magnitude (EVM) performance representing quality of transmission signal are provided. The apparatus and the method suppress an image frequency component generated due to mismatch of IQ channels in order to transmit/receive a large amount of data without distortion in 4th generation wireless communication standard candidate technologies such as a Long Term Evolution (LTE) system and a mobile WiMax system. The apparatus includes a LOcal frequency (LO) buffer including an amplifier. The LO buffer controls the gain and the phase of the amplifier using a control bit for controlling resistor connection.

Abstract: An apparatus and a method for calibrating a Voltage Controlled Oscillator (VCO) using a fast frequency comparison based on phase manipulation are provided. The calibrating apparatus includes a phase shifter for comparing an input reference frequency and an input divided frequency and shifting a phase of the reference frequency to make the phase of the reference frequency align with a phase of the divided frequency; a frequency comparator for determining which one of the phase-shifted reference frequency and the divided frequency is higher; and a cap-bank control for determining a frequency to use based on a comparison result of the frequency comparator.

Abstract: A receiver apparatus for tracking and rejecting a Transmit (Tx) signal in a wireless communication system and an operation method thereof are provided. The receiver apparatus includes a controller for receiving channel frequency information of the Tx signal and for controlling an operation for tracking and rejecting a frequency of the Tx signal; a phase locked loop for generating an oscillation frequency by generating a control voltage according to the channel frequency information of the Tx signal under the control of the controller and for filtering a signal corresponding to the oscillation frequency among signals input to a low noise amplifier; and the low noise amplifier for amplifying power while minimizing noise of a signal filtered by the phase locked loop.

Abstract: A low noise amplifier (LNA) for ultra wide band receives and amplifies identical RF signals in different frequency bands, and includes more than one pair of narrow band LNAs coupled in parallel, and a load circuit which increases load impedance of the entire circuit of the narrow band LNAs. The LNA can not only amplify the RF signal in the UWB but also obtain the low noise and the high gain that are features of the conventional narrow band LNA.

Abstract: Provided are a receiving circuit including a balun circuit and a notch filter, and an operating method thereof. The receiving circuit includes a transformer, a notch filter, and a mixer. The transformer converts a single input signal to a differential input signal using a first tap. The notch filter blocks a specific frequency band of the single input signal by connecting a second tap with the first tap of the transformer using a condenser.

Abstract: A fast mode switching frequency synthesizing apparatus and method for operating in low power consumption. In the frequency synthesizer, according to a mode control signal, an SSB mixer selectively generates and outputs a signal having a frequency which is identical to an input signal RF or outputs a signal having a frequency which is a synthesized frequency of the input signals RF and LO. Frequency synthesized signals having a frequency which is a sum of frequencies of the input signals RF and LO, or a difference of frequencies therebetween, may be generated by changing wiring of a path switch according to a phase control signal.

Abstract: A frequency synthesizing apparatus and method for a multi-band radio frequency (RF) receiver is provided. The frequency synthesizing apparatus includes a simple circuit configuration with a single SSB mixer and thus, may synthesize six high frequency signals. Signals to be inputted into the SSB mixer include a first signal and a second signal. The first signal is generated based on a VCO and a PPF. Also, the second signal is selected from a plurality of frequency divided signals which are generated by dividing a signal generated in the VCO via a plurality of dividers.

Abstract: A frequency synthesizing apparatus and method for a multi-band radio frequency (RF) receiver is provided. The frequency synthesizing apparatus includes a simple circuit configuration with a single SSB mixer and thus, may synthesize six high frequency signals. Signals to be inputted into the SSB mixer include a first signal and a second signal. The first signal is generated based on a VCO and a PPF. Also, the second signal is selected from a plurality of frequency divided signals which are generated by dividing a signal generated in the VCO via a plurality of dividers.

Abstract: A frequency synthesizing apparatus and method having an injection-locked quadrature VCO in an RF transceiver is provided. In the frequency synthesizer, an I signal following a frequency of a high frequency signal that is input using the injection-locked quadrature VCO and a Q signal thereof are simultaneously generated to have an appropriate driving power. Accordingly, the I signal and the Q signal thereof that are generated in the injection-locked quadrature VCO may be utilized as a local signal for frequency up/down-conversion, without being buffered. An output of an SSB mixer may be directly input into the injection-locked quadrature VCO. Also, high frequency signals that are generated in another circuit such as the SSB mixer, a PLL, or a VCO may be selected to be input into the injection-locked quadrature VCO by a selector.