Samsung Electro-mechanics Co., Ltd.

Seung Min Oh

Hyo Seok Kwon

Yoo Sam Na

Byeong Hak Jo

Hyeon Seok Hwang

Hyun Hwan Yoo

Seung Won Seo

Ki Won Choi

Won Jin Baek

Kyoung Seok Park

Jeong Ki Choi

Gi Won Choi

There is provided a frequency synthesizer including a multi-band voltage controlled oscillator having a plurality of voltage controlled oscillating cores outputting oscillation frequencies having different bands according to an input control voltage. Each of the voltage controlled oscillating cores outputs a frequency band divided into a plurality of bands, and the voltage controlled oscillating core operates by each of the divided bands, and one of the voltage controlled oscillating cores operates in one of the bands according to the control voltage. The frequency synthesizer further includes a comparator unit and an oscillation band-determining unit. The comparator unit compares the control voltage with a pre-set reference voltage range. The oscillation band-determining unit changes the band where the voltage controlled oscillating core operates into another one of the bands when the control voltage is out of the pre-set reference voltage range.

Frequency synthesizer having multi-band voltage controlled oscillator

A frequency conversion circuit comprises an input stage composed of one or more transistors, the input stage outputting a current corresponding to a voltage-type RF signal which is input to the gate of the transistor; a frequency conversion stage receiving an LO signal, causing the output RF signal to transit by the frequency of the LO signal so as to output an IF signal, and detecting an output voltage of the IF signal; a bleeding transistor connected to the input stage, supplying a current corresponding to a DC voltage, applied to a gate-source stage thereof, as a bleeding current to the transistor of the input stage, and in an AC manner, operating complementarily with the input stage to control a current flowing in the frequency conversion stage; a common mode feedback circuit comparing an output voltage provided from the frequency conversion stage with a preset reference voltage, adjusting the output voltage such that the output voltage is equalized to the reference voltage, and directly feeding the adjusted output voltage to the bleeding transistor; and a load stage composed of resistors and distributing a power supply voltage to apply to the frequency conversion stage.

Frequency conversion circuit

There is provided a bias current generating apparatus capable of providing a bias current where a characteristic change is compensated, to one of an analog circuit and RF circuit where various characteristic changes occur according to a temperature, by generating bias currents having a plurality of temperature coefficients. The apparatus includes: a positive temperature coefficient current generator generating a positive temperature coefficient current in direct proportion to an absolute temperature; a zero temperature coefficient current generator generating a zero temperature coefficient current constant regardless of the absolute temperature; and an adjustable temperature coefficient current generator generating and outputting an adjustable temperature coefficient current by amplifying the positive temperature coefficient current by A times, amplifying the zero temperature coefficient current by B times, adding the two amplified temperature coefficient currents, wherein a temperature coefficient of the adjustable temperature coefficient current is varied by adjusting sizes of the A and B.

Bias current generating apparatus with adjustable temperature coefficient

The present invention relates to an exponential function generator which is realized with only CMOS element without BJT element, not limited by the physical properties of the element or a square circuit, and not complicated in its configuration, and a variable gain amplifier using the same. The exponential function generator includes a voltage-current converter, 1to ncurve generators for mirroring the current from the voltage-current converter, outputting a current adjusted according to a predetermined ratio, and an output end for outputting the sum of the current from the 1to ncurve generators. The exponential current generator is configured to generate the current exponentially adjusted according to the control voltage.

Exponential function generator and variable gain amplifier using the same

The present invention relate to a wideband frequency generating apparatus using a frequency dividing method of dividing a frequency signal of a voltage control oscillator to expand a frequency generating range. The apparatus comprises an oscillator unit generating a predetermined frequency signal, a mixer having a first input coupled to the oscillator unit to generate a difference signal by mixing the predetermined frequency signal with a signal inputted to a second input of the mixer, a first switch tuned on/off and coupling the predetermined frequency signal to an output of the mixer, a second switch turned on/off and coupling the output of the mixer to the second input of the mixer to form a feedback loop, a &#xbd; frequency divider dividing the output of the mixer by &#xbd; to generate a divided signal, a third switch tuned on/off and coupling the divided signal of the &#xbd; frequency divider to the second input of the mixer unit, and a control logic unit generating on/off control signals turning on/off the mixer, the first switch, the second switch, the third switch in accordance with a selection of frequency generating ranges.

Device for generating wide tunable frequency using frequency divider

A frequency conversion apparatus having a mixer eliminates phase miss-matching between two intermediate frequency (IF) signals having the same frequency and a 90 degree difference in phase. The frequency conversion apparatus for compensating for phase mismatching of first and second IF signal in response to an RF input signal transmitted through an RF input terminal includes a quadrature signal generator (QSG) outputting first and second oscillating frequency signals having a 90 degre difference in phase, a first mixer mixing the RF input signal with a first resultant frequency signal having a first resultant phase and generated from the first oscillating frequency signal and an inverted signal of the second oscillating frequency signal, and a second mixer mixing the RF signal with a second resultant frequency signal having a second resultant phase and generated from the second oscillating frequency signal and an inverted signal of the first second oscillating frequency signal. The frequency conversion apparatus having a mixer improving a signal-to-noise (SN) ratio and increasing an image-rejection ratio by correcting phase miss-matching.

Mixer and frequency conversion apparatus for improving phase-mismatching

A linear channel select filter for an Intermediate Frequency selector of a satellite broadcasting tuner, linearly changes a desired frequency by adjusting an output current, and includes: a transconductance (GM) current cell controller for determining a control voltage according to a select signal, generating the output current according to an differential input voltage, linearly controlling the output current according to the control voltage, and providing a linearly variable resistance according to the linearly controlled output current, and a capacitor circuit coupled to the GM cell controller to provide a capacitance to generate a cutoff frequency voltage according to the output current and the variable resistance. An occupying area and a size of the filter are reduced.

Linear channel select filter

Disclosed is a quadrature signal generator for generating an in-phase signal and a quadrature-phase signal, which is capable of generating a quadrature signal having the same frequency as a differential oscillating frequency, using a feedback control system. The quadrature signal generator includes an oscillator for generating a differential oscillation frequency signal having predetermined differential oscillation frequencies; a feedback type frequency doubler for generating a differential frequency signal having differential frequency components corresponding to differential frequency components of a frequency sum signal obtained by summing the differential oscillation frequency signal received from the oscillator and a differential feedback signal received at the differential feedback terminal; and a frequency divider for dividing the differential frequency signal received at the differential input terminal thereof by 2, thereby generating a quadrature signal consisting of two differential output frequency signals to supply at least one differential output frequency signal of the quadrature signal to the feedback type frequency doubler as the differential feedback signal.

Quadrature signal generator with feedback type frequency doubler

The present invention relates to a variable oscillation frequency resonance circuit and voltage controlled oscillator using the same, which includes an inductance element, frequency varying means, and oscillation band varying means. The oscillation band varying means is provided with one or more capacitance element pairs and one or more differential switching element pairs each being arranged between capacitance elements of each of the capacitance element pairs, with differential switching elements of each of the differential switching element pairs being arranged in parallel with each other, to allow a corresponding capacitance element pair to be connected to the inductance element in response to second control signals.

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Chunlabook-do, South Korea

Seung Min Oh