Patent application number | Description | Published |
20090051442 | TRANSIMPEDANCE AMPLIFIER CIRCUIT FOR OPTICAL RECEIVER IN OPTICAL COMMUNICATION SYSTEM - A transimpedance amplifier circuit for an optical receiver in an optical communication system in which a range of an increase/decrease in bandwidth according to gain change is reduced by a bandwidth adjustor. The circuit includes: a photodiode (PD) for generating a current signal by photoelectric conversion of an input optical signal; a Transimpedance Amplifier (TIA) for converting the current signal input from the photodiode into a voltage signal; an auto gain adjustor for adjusting feedback resistances of the transimpedance amplifier; a photodiode parallel capacitor reducer for reducing a parallel capacitor current of the photodiode; and a bandwidth adjustor for reducing a range of an increase/decrease in bandwidth according to an increase/decrease in gain of the transimpedance amplifier. | 02-26-2009 |
20090072905 | VARIABLE GAIN AMPLIFIER HAVING WIDE GAIN VARIATION AND WIDE BANDWIDTH - There is provided a variable gain amplifier that is implemented with a CMOS device and has wide band variation and wide bandwidth by a predetermined exponential function. A variable gain amplifier having wide gain variation and wide bandwidth according to an aspect of the invention may include: a differential amplification section differentially amplifying an input signal according to a gain adjustment signal; and a gain adjustment section supplying the gain adjustment signal on the basis of an approximated exponential function determined according to a predetermined bias current, and adjusting a gain of the differential amplification section. | 03-19-2009 |
20090140815 | LOW NOISE AMPLIFIER FOR ULTRA WIDE BAND - 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. | 06-04-2009 |
20100014866 | Digital Automatic Gain Control Apparatus and Method in Burst Mode Optical Receiver - A transimpedance amplifier for a burst mode optical communication converts a burst current signal into differential output voltage signals. Using a multi-level digital AGC mechanism, the transimpedance amplifier is rapidly adapted to a burst signal whose amplitude varies in a wide range. By using an adaptive level detection method, a multi-level digital AGC can be implemented without using ADC. In addition, because the transimpedance amplifier uses a selective reset generation scheme that performs a reset operation for itself after a high power burst, a burst mode operation can be performed without external reset signals. Accordingly, the transimpedance amplifier can be integrated with an optical detector within a TO-can. Furthermore, the transimpedance amplifier can have the burst mode capability and the best sensitivity. | 01-21-2010 |
20100156542 | LOW VOLTAGE FREQUENCY SYNTHESIZER USING BOOSTING METHOD FOR POWER SUPPLY VOLTAGE OF CHARGE PUMP - Provided is a low voltage frequency synthesizer using a boosting method for a power supply voltage of a charge pump. The low voltage frequency synthesizer includes a phase/frequency detector (PFD) that receives and compares a reference frequency and a feedback frequency to output a comparison signal, a charge pump that receives the comparison signal to output a current corresponding to the comparison signal, a low-pass filter (LPF) that generates a voltage corresponding to the output current of the charge pump, a voltage controlled oscillator (VCO) that receives the voltage of the LPF, amplifies the voltage to generate a boosting voltage, and outputs a frequency corresponding to the received voltage, and a DC converter that receives the boosting voltage of the VCO, converts the boosting voltage into a DC voltage, and applies the DC voltage as a power supply voltage of the charge pump. Since the supply voltage of the charge pump is provided from the LC-circuit-based VCO, the frequency synthesizer has superior characteristics such as a wide locking range, low phase noise, and the prevention of performance degradation caused by an external environment or process variations. | 06-24-2010 |
20110150138 | HIGH LINEARITY MIXER AND DIRECT CONVERSION RECEIVER USING THE SAME - A direct conversion receiver includes: a high linearity mixer device including a sampler unit charge-sampling an input current according to a sampling frequency, and a buffer unit receiving an output signal from the sampler unit while having a low input impedance, amplifying the received signal, and outputting a current signal; and a filter device decimating an output signal from the mixer device and FIR-filtering the decimated signal. | 06-23-2011 |
20130165059 | BEAMFORMING APPARATUS AND METHOD IN MOBILE COMMUNICATION SYSTEM - Provided is a beamforming apparatus in a receiver in a mobile communication system. The beamforming apparatus includes a Local Oscillator (LO) signal generator for generating an LO signal; a phase shifter for generating a predetermined number of phase-shifted LO signals with respect to the generated LO signal; a switching network for mapping the phase-shifted LO signals to RF signals received via a plurality of receive paths; and a mixer for mixing the RF signals with the mapped LO signals to down-convert a frequency of the RF signals. | 06-27-2013 |
20130194036 | ENVELOPE DETECTION APPARATUS DYNAMICALLY CONTROLLED IN RESPONSE TO INPUT SIGNAL AND ENVELOPE DETECTION METHOD THEREOF - An envelope detection apparatus dynamically controlled in response to an input signal and an envelope detection method thereof are provided. The envelope detection apparatus includes an envelope detector configured to output an envelope of an input signal. The envelope detection apparatus further includes a detection band determination unit configured to determine a detection band based on the input signal. The envelope detection apparatus further includes a detection band controller configured to control a detection band of the envelope detector based on the determined detection band. | 08-01-2013 |
20130272341 | TEMPERATURE SENSOR AND TEMPERATURE MEASUREMENT METHOD THEREOF - A temperature sensor that senses a temperature on the basis of a relaxation oscillator, includes: a bias circuit unit that outputs a bias current increasing with an increase in temperature; a capacitor voltage unit that charges a capacitor with the bias current and discharges the current when receiving a control signal; a pulse generating unit that outputs a pulse when the voltage of the capacitor is higher than a reference voltage, changes the pulse width of the pulse, and transmits the pulse corresponding to the control signal to the capacitor voltage unit; and a counter unit that counts and outputs, as a digital value, the number of pulses outputted from the pulse generating unit, on the basis of a reference frequency. | 10-17-2013 |
20140169512 | DIRECT CONVERSION RECEIVER INCLUDING A CHARGE AREA DECIMATION FILTER - A direct conversion receiver includes: a high linearity mixer device including a sampler unit charge-sampling an input current according to a sampling frequency, and a buffer unit receiving an output signal from the sampler unit while having a low input impedance, amplifying the received signal, and outputting a current signal; and a filter device decimating an output signal from the mixer device and FIR-filtering the decimated signal. | 06-19-2014 |