摘要:
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.
摘要:
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.
摘要:
Disclosed is a programmable complex mixer. In accordance with the embodiments of the present invention, it is possible to control an output by programming paths and signs of internal signals in a complex mixer to reduce a processing bandwidth, power consumption, and a chip area in a transceiver, thereby improving performance of a transceiver.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
An all digital phase-locked loop (ADPLL) includes: a phase counter accumulating a frequency setting word value and the phase of a digitally controlled oscillator (DCO) clock and detecting a fine phase difference between a reference clock and a retimed clock; a phase detector detecting a digital phase error value compensating for a phase difference between the frequency setting word value and the DCO clock according to the fine phase difference to detect a digital phase error value; a digital loop filter filtering the digital phase error value and controlling PLL operational characteristics; a lock detector generating a lock indication signal according an output of the digital loop filter; a digitally controlled oscillator varying the frequency of the DCO clock according to the output from the digital loop filter; and a retimed clock generator generating the retimed clock by retiming the DCO clock at a low frequency.
摘要:
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.
摘要:
An automatic gain-control method for a communication system is comprised of determining a communication distance between the first and second transceivers and controlling gain values of transception stages of the first and second transceivers in correspondence with the communication distance.
摘要:
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 RF signal; and a digital processing unit configured to process a digital signal from the sub-sampling A/D conversion unit according to a system clock generated by using the reference frequency signal from the clock generation unit.