Abstract:
A lock detector and a clock generator including the same are disclosed. A lock detector includes a counter unit which counts a non-matching section of a first signal and a second signal to provide a count value, the first signal and the second signal being comparison result signals obtained by comparing a phase of a reference signal with a phase of a comparison signal, and a lock detection unit which outputs a lock detection signal based on a result of comparing the count value with the reference value. Accordingly, a lock state of the phase-locked loop can be detected rapidly and exactly.
Abstract:
Disclosed is an apparatus for controlling a duty ratio of a signal that includes a clock control unit configured to generate a plurality of control signals based on an input signal, a half-cycle generation unit configured to generate a multiplied signal by use of the input signal and a delay signal that is obtained by delaying the input signal based on a delay control voltage, and divide the multiplied signal to generate a first division signal and a second division signal that are in inverse relation to each other, a comparator unit configured to compare a pulse width of the first division signal with a pulse width of the second division signal based on the control signal provided by the clock control unit, and output a delay control signal corresponding to a result of the comparison, and a control voltage generation unit configured to output a delay control voltage.
Abstract:
An error calibrating apparatus of an array antenna system according to an exemplary embodiment of the present invention is an error calibrating apparatus of an array transmitting antenna system having a plurality of array antennas and includes a calibrating signal generator which generates an error calibrating signal as a single frequency signal, in an area which does not interfere with a passband of a transmitted signal; an array RF transmitter which upwardly converts the transmitted signal into an RF band to transmit the signal to the plurality of array antennas; an error calibration estimator which correlates the error calibrating signal and the receiving single frequency signal received by passing through the array RF transmitter to estimate a transfer function of the array RF transmitter and extract a filter coefficient using the estimated transfer function; and a complex filter which calibrates an error of the transmitted signal by applying the filter coefficient to output the corrected transmitted signal to the array RF transmitter.
Abstract:
Provided is a second order loop filter (LF). The second order LF includes: an operational amplifier including a first input, a second input receiving a differential input of the first input, and an output; an inverter inverting a signal output from the output of the operational amplifier to output an inverted signal; a first resistor connected to between the first input and a first node; a second resistor connected to between the output of the operational amplifier and the first node; a third resistor connected to between the first input and an input signal; a first capacitor connected to between the second input and the first node; a second capacitor connected to between the output of the operational amplifier and an output of the inverter; and a third capacitor connected to between the output and the first input of the operational amplifier, wherein the second input is connected to a ground voltage.
Abstract:
Provided is a charge pump circuit having a current mirror structure, including a first voltage controller including a plurality of first resistors and a plurality of first switches, and in response to a switching control signal corresponding to a bias current, driving the plurality of first switches to allow a current path passing through the plurality of first resistors to bypass, thereby controlling a voltage level of an output end, a second voltage controller including a plurality of second resistors and a plurality of second switches, and in response to the switching control signal, driving the plurality of second switches to allow a current path passing through the plurality of second resistors to bypass, thereby controlling a voltage level of an output end to correspond to the voltage of the output end of the first voltage controller.
Abstract:
Provided is a method of generating a driving signal for driving a dual mode supply modulator for a power amplifier. The method includes obtaining an envelope of a complex baseband signal to be transmitted, comparing the envelope of the complex signal with a preset threshold value, when a current envelope of the complex signal is the preset threshold value or greater or when there is a result having the preset threshold value or greater in previous N comparisons, outputting a digital board output signal configured with a first logic level through a digital-to-analog converter; and when the current envelope of the complex signal is smaller than the preset threshold value and when there is no result having the preset threshold value or greater in the previous N comparisons, outputting a digital board output signal configured with a second logic level through the digital-to-analog converter.
Abstract:
A frequency comparator outputs an input reference signal and a comparison target signal as pulse-form signals, and is charged or discharged with a voltage corresponding to the reference signal to output a reference voltage having a variable first frequency range, and charged or discharged with a voltage corresponding to the comparison target signal to output a comparison target voltage having a variable second frequency range. The frequency comparator compares the reference voltage having the first frequency range and the comparison output voltage having the second frequency range.
Abstract:
Disclosed are a method and apparatus for canceling self-interference signals in a communication system. A first communication node includes a signal transmission unit configured to generate a first RF signal, an antenna module configured to transmit the first RF signal generated by the signal transmission unit and receive a second RF signal from a second communication node, a signal reception unit configured to process the second RF signal and a self-interference signal caused by the first RF signal, and an SIC circuit configured to cancel the self-interference signal. The SIC circuit includes a DSIC circuit for canceling the self-interference signal in a digital domain and an ASIC circuit and an HSIC circuit for canceling the self-interference signal in an analog domain. Accordingly, the performance of the communication system may be enhanced.
Abstract:
A delta-sigma modulator and a transmitter apparatus including the same are disclosed. The delta-sigma modulator includes a first integrator, a second integrator, a first comparator configured to compare an output signal of the second integrator and a reference signal, and output a first comparison signal, a second comparator configured to compare the output signal of the second integrator and the reference signal, and output a second comparison signal, a first DAC configured to output the first signal corresponding to the first comparison signal and the second comparison signal, a second DAC configured to output the second signal corresponding to the first comparison signal and the second comparison signal, a delayer configured to generate a delayed signal that delays the first comparison signal and the second comparison signal by a predetermined time, and an output DAC configured to generate an output signal having a multi-level corresponding to the delayed signal.
Abstract:
A direct current-to-direct current (DC-DC) converter providing multiple operation modes includes a buck power stage configured to lower an input voltage, a boost power stage configured to increase the input voltage, and a multi-mode controller configured to control the buck power stage and the boost power stage, wherein the multi-mode controller is configured to generate a signal to control the buck power stage and the boost power stage according to the input voltage and an output voltage, and control the buck power stage and the boost power stage using the signal.