Electronics and Telecommunications Research Institute

Seon-Ho Han

Hyun Kyu Yu

Bon Tae Koo

Mun Yang Park

Cheon-Soo Kim

Hyun-Kyu Yu

Ik Soo Eo

Jang Hong Choi

Seong-Do Kim

Mun-Yang Park

Yong-Sik Youn

Young-Su Kwon

Kyung Hwan Park

Min Sang Park

Sang-Gug Lee

Young-Jun Kim

Sang-Kyun Kim

Byung-Do Yang

Nam-soo Kim

Hyun Ho Boo

Jang-Hong Choi

Ki-Hyuk Sung

Lee-Sup Kim

Nam Nguyen Hoai

Jae-Hong Jang

Ki-Su Kim

Disclosed is a phase shift circuit including an input circuit for generating first to fourth internal signals based on an in-phase signal, a complementary in-phase signal, a quadrature phase signal, and a complementary quadrature phase signal and a switching circuit for outputting first to fourth shift signals based on the first to fourth internal signals. The input circuit includes a first transistor connected between a ground node and a first node to operate based on the in-phase signal and the first bias signal, a second transistor connected between the ground node and a second node to operate based on the complementary in-phase signal and the first bias signal, a third transistor connected between the ground node and the first node to operate based on the second bias signal, and a fourth transistor connected between the ground node and the second node to operate based on the second bias signal.

Phase shifter for linearly shifting phase of input signal based on phase control signals

Disclosed are a digital CDR circuit and a feedback loop circuit including the same. The digital CDR circuit includes a phase detector that receives an input signal and outputs a phase detection result signal corresponding to a determination result for a sampling time based on the input signal, a charge pump that receives the phase detection result signal and outputs an amplified signal obtained by multiplying the phase detection result signal by a gain, a loop filter that receives the amplified signal and filters the amplified signal to output a filtered signal, and a phase shift control code generator that generates a control signal for controlling a phase of a signal based on the filtered signal, and the input signal includes plural data signals and plural error signals, and the data signals and the error signals are digital signals which are quantized based on a signal magnitude.

Digital clock and data recovery circuit and feedback loop circuit including the same

Disclosed is a phase shifter, which includes a signal generator that generates a first signal and a second signal having a phase orthogonal to a phase of the first signal, and outputs the first signal and the second signal, an operator that generates a first current and a second current, and amplifies the first current and the second current, and a signal converter converting a first digital signal and a second digital signal. The operator includes an input circuit converting the first signal and the second signal, a path selection circuit determining paths of the generated first current and the generated second current, and a cascode circuit buffering the first current and the second current. The operator sums the first current and the second current, controls a vector of the first current and a vector of the second current, and generates a voltage signal through an output load.

Phase shifter with function of controlling beam side lobe

Disclosed is a phase demodulator, which includes a transmitter that outputs a reference signal to a target, a receiver that receives a target signal generated in response to the reference signal from the target, and a demodulation processor that demodulates the target signal, and the demodulation processor includes a phase controller that outputs a first phase signal based on the reference signal, a phase shifter that delays a phase of the first phase signal to output a first delayed signal, a mixer that outputs a first mixing signal based on the target signal and the first delay signal, and an amplifier that outputs a first feedback signal generated by amplifying the first mixing signal to the phase controller.

Phase demodulator with negative feedback loop

Provided is a phase array receiver. A phase array receiver according to an embodiment of the present invention includes a plurality of antennas, a plurality of low-noise amplifiers, a plurality of phase shifters, a plurality of transconductors, and a frequency mixer. A plurality of low-noise amplifiers amplify RF signals received from the plurality of antennas. The plurality of phase shifters adjusts the phase of the RF signals to generate a plurality of RF phase adjustment signals. The plurality of transconductors convert a plurality of RF phase adjustment signals into a plurality of RF current signals based on the gain control signal. The frequency mixer converts a sum of the plurality of RF current signals into a mixed current signal. According to the inventive concept, the linearity of the signal processing may be improved and the area for the implementation of the phase array receiver may be reduced.

Phase array receiver

A bandpass filter that provides a wide gain control range is provided. The bandpass filter performs channel filtering and gain control while maintaining the bandpass characteristic of the bandpass filter. The bandpass filter enables gain control for a wide signal amplitude range while maintaining performance characteristics, such as an out-of-band attenuation ratio capable of high linearity and good pass-band flatness.

Bandpass filter providing wide gain control range

Disclosed are an accumulator for reducing nonlinearity of a data converter and a data weighted average device including the accumulator. According to the accumulator including a register configured to output input data according to a clock signal; a first adder configured to receive a digital input signal having any bit width and an output signal from the register to perform an add operation; a preset unit configured to output a preset value or a 0 value according to whether a carry of the first adder is generated; and a second adder configured to receive an output signal of the first adder and an output signal of the preset unit to perform the add operation and input the add operation to the register and the data weighted average device including the accumulator, it is possible to improve the nonlinearity occurring in the data converter by generating a number of DAC codes in addition to 2DAC codes.

Accumulator and data weighted average device including the accumulator

A digital RF receiver does not use a separate receiver according to a mode and a band for multi-mode reception, MIMO reception, and bandwidth extension reception, and changes only setting variables in a single receiver structure so as to implement multi-mode reception, MIMO reception, bandwidth extension reception, and/or simultaneous multi-mode operation, such that complexity of the receiver, development cost, and power consumption can be reduced.

Digital radio frequency (RF) receiver

The present invention relates to a single frequency synthesizer based FDD transceiver. A single frequency synthesizer generates and provides a carrier frequency so that frequency up-conversion and frequency down-conversion can be performed at the time of transmission and reception. Accordingly, the area, power consumption, and design complexity of the entire system can be reduced, and the performance of the system can be improved.

Single frequency synthesizer based FDD transceiver

The inventive concept relates to a wireless communication receiver. The wireless communication receiver includes a second off-chip RF filter, an RF-to-digital converter and a digital pre-processor processing a signal converted into a digital. The RF-to-digital converter converts an RF signal being received into a digital signal of DC frequency band or intermediate frequency band and has a dynamic range that can process a wanted RF band signal and unwanted signals near to the wanted RF band signal. The digital pre-processor digitally controls a signal gain to transmit it to a modulator/demodulator.

Subsampling receiver using interstage off-chip RF band pass filter

Provided is a frequency selective noise canceller including: a frequency selective single to differential converter having a band pass filter function, converting a received single input signal into a differential signal in a wanted signal pass frequency band and into a common mode signal in an unwanted signal frequency band; and a common mode rejector functioning as a load having an arbitrary impedance with respect to the differential signal outputted from the frequency selective single to differential converter and functioning as a filter with respect to the common mode signal.

Subsampling based receiver using frequency selective noise canceller

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 subsampling 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.

Digital receiver

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.

Wireless transceiving apparatus for variability of signal processing band

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.

Variable capacitor circuit having linear capacitance variation and voltage controlled oscillator using the same

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.

Growing community of inventors

Daejeon, South Korea

Seon-Ho Han