Abstract: A clock and data recovery circuit includes a voltage controlled oscillator for generating an output clock according to a control voltage signal, a loop filter for outputting the control voltage signal according to a current output, a charge pump unit for outputting the current output according to an error signal, and a controller for determining a run length corresponding to input data based on the output clock from the voltage controlled oscillator. The controller further controls at least one of the voltage controlled oscillator, the loop filter and the charge pump unit according to the run length to dynamically adjust loop bandwidth. A method of adjusting loop bandwidth is also disclosed.

Abstract: An equalizer and a related equalizing method for equalizing signal reflection caused by a stub at a transmitting end are provided. The equalizer includes a summing device and a delay device. The summing device is utilized for adding a feedback delay signal to the input signal to generate the equalized signal. The delay device is coupled to the summing device, and utilized for delaying the equalized signal to generate the feedback delay signal. Wherein the delay device has a variable delay time and the variable delay time is a non-integer multiple of a bit time of the input signal.

Abstract: A receiving device includes a mixer, an AC coupling circuit, a post-stage circuit, and a DC offset calibration circuit. The mixer is utilized for mixing an input signal with a local oscillating (LO) signal from an oscillator to generate a converted signal. The AC coupling circuit is coupled to the mixer and utilized for reducing at least one portion of DC offset of the converted signal to generate a filtered signal. The post-stage circuit is coupled to the AC coupling circuit and utilized for processing the filtered signal to generate an output signal. The DC offset calibration circuit is coupled to the post-stage circuit and utilized for providing at least a compensation current for the post-stage circuit to reduce DC offset of the output signal.

Abstract: A high linearity mixer circuit includes a commutation network comprising four switches to provide an electrical coupling between a first pair of circuit nodes and a second pair of circuit nodes, whereas the coupling has two states and is controlled by a pair of complementary logical signals. The mixer circuit further comprises a first pair of current-sourcing devices coupled to the first pair of circuit nodes and a second pair of current-sourcing devices coupled to the second pair of circuit nodes. The mixer circuit further includes a pair of capacitors to provide AC coupling, either between the first pair of circuit nodes and a first external circuit, or between the second pair of circuit nodes and a second external circuit.

Abstract: A reference assisted control system and method thereof are disclosed. The method comprises: receiving a first input signal and a second control signal; generating a first intermediate signal in accordance with a difference between the first input signal and the first output signal; filtering the second control signal to generate a second intermediate signal; performing a weighted sum of the first intermediate signal and the second intermediate signal to generate the control signal; and outputting the first output signal in accordance with the control signal.

Abstract: Methods and apparatuses for alleviating charge leakage of VCO for phase lock loop are disclosed. The method comprises: receiving an input signal; generating an error signal representing a timing difference between the input signal and an output signal; filtering the error signal into a control signal; buffering the control signal into a buffered control signal; and generating the output signal in accordance with the buffered control signal. Buffering the control signal comprising using a high input resistance and low output resistance buffer circuit.

Abstract: An apparatus and a method for achieving lock-in of a phase-locked loop (PLL) are disclosed. The PLL receives a reference clock and generates an output clock according to the reference clock. The method comprises: adjusting an oscillation frequency of a controlled oscillator of the PLL close to a desired frequency by counting the number of rising edges of a first clock in a number of a second clock cycles; aligning a rising edge of a third clock and a rising edge of a fourth clock by temporarily changing the oscillation frequency of the digitally controlled oscillator; and locking the phases of the third and fourth clocks by a phase detector of the PLL, wherein the first and the third clocks correspond to the output clock and the second and fourth clocks correspond to the reference clock.

Abstract: A soft-start device including a current source, a first transistor, and a second transistor is described. The first transistor is coupled to the current source, and an amount of current conducted by the first transistor is determined according to a voltage. The second transistor is also coupled to the current source, and an amount of current conducted by the second transistor is determined according to a fixed bias. An initial voltage value of the voltage is smaller than a voltage value of the fixed bias. However, after a soft start, the voltage value of the first voltage is increased gradually to be larger than the voltage value of the fixed bias, such that the soft start may be implemented smoothly.

Abstract: A hybrid coarse-fine time-to-digital converter is disclosed. The hybrid coarse-fine time-to-digital converter is configured to receive a first input signal and a second input signal and to generate a digital output that corresponds to the time difference of between a rising edge of the first input signal and a rising edge of the second input signal. The hybrid coarse-fine time-to-digital converter comprises a coarse time-to-digital converter, a fine time-to-digital converter, and a correlated output generator.

Abstract: An apparatus and a method for achieving lock-in of a phase-locked loop (PLL) are disclosed. The PLL receives a reference clock and generates an output clock according to the reference clock. The method comprises: adjusting an oscillation frequency of a controlled oscillator of the PLL close to a desired frequency by counting the number of rising edges of a first clock in a number of a second clock cycles; aligning a rising edge of a third clock and a rising edge of a fourth clock by temporarily changing the oscillation frequency of the digitally controlled oscillator; and locking the phases of the third and fourth clocks by a phase detector of the PLL, wherein the first and the third clocks correspond to the output clock and the second and fourth clocks correspond to the reference clock.

Abstract: The present invention provides a multi-phase layout structure and method. The layout structure comprises: a first layout layer; a second layout layer substantially parallel to the first layout layer; a plurality of traces, each transmitting a signal, and the plurality of signals having a phase difference between each other; wherein a horizontal coupling capacitance is provided between two neighboring traces configured on the same layer of the first layout layer and the second layout layer, a vertical coupling capacitance is provided between two neighboring traces configured on different layers of the first layout layer and the second layout layer, and the plurality of traces have substantially the same total coupling capacitance wherein the total coupling capacitance is defined by the horizontal coupling capacitance and the vertical coupling capacitance.

Abstract: This invention provides an equalization apparatus for equalizing an input signal on a cable. The equalization apparatus comprises a cable equalizer for equalizing a cable attenuation effect of the input signal to output a first equalization signal; and a stub equalizer for equalizing a stub effect of the first equalization signal to output an outputting equalization signal.

Abstract: This invention discloses a crystal oscillator, in which by appropriately designing the gain of an amplifier to achieve high trans-conductance and low power consumption. This crystal oscillator includes a first pad, coupled to a first node of a crystal, for receiving a crystal oscillating signal outputted from the crystal; an amplifier, coupled to the first pad, for amplifying the crystal oscillating signal to generate an amplifying signal; an inverter, coupled to the amplifier, for inverting the amplifying signal; and a second pad, coupled to a second node of the crystal, for outputting an oscillating signal to the crystal.

Abstract: A digitally controlled LC-tank oscillator is constructed by connecting different tuning circuits to a LC tank. The tuning circuit includes a single bank of tuning cells, a dual bank of tuning cells, or a fractional tuning circuit. Each of said tuning cells in the tuning circuit includes a tuning circuit element and a memory cell.

Abstract: An amplifier includes: a class AB input stage, receiving an input signal, for generating an inner signal according to the input signal; class AB output stage, includes: a biasing circuit, for providing a first voltage and a second voltage according to the inner signal; and an output stage, for generating an output signal according to the first voltage and the second voltage; wherein a voltage difference between the first voltage and the second voltage generated by the biasing circuit is corresponding to the input signal.

Abstract: A switch circuit includes a pair of metal oxide semiconductor (MOS) switches and an adjusting unit. Each of the MOS switches has an input terminal and an output terminal. The MOS switches receive a pair of differential input voltages at the input terminals thereof, and output a pair of differential output voltages at the output terminals thereof when the MOS switches conduct. The adjusting unit changes a difference between common mode levels of the input terminals and the output terminals of the MOS switches so as to adjust linearity of differential mode resistances of the MOS switches.

Abstract: A bandwidth-adjustable filter includes an operational amplifier, a first resistor, a first capacitor and a first resistor ladder circuit. The operational amplifier has a negative input terminal and a positive input terminal. The first resistor is coupled to one of the input terminals of the operational amplifier. The first capacitor is coupled to the first resistor. The first resistor ladder circuit is coupled in parallel to the first resistor for changing the resistance of the first resistor so as to adjust the bandwidth of the filter.

Abstract: A delay adjustor for adjusting the delay time of a signal, the adjustor comprising: a first capacitance unit and a variable capacitance unit serially coupled to the first capacitor wherein the capacitance of the variable capacitance unit is adjusted according to a first control signal and the variable capacitance unit comprises a plurality of second capacitors and at least a first switch coupled to the at least one capacitor of the second capacitors.

Abstract: A bandwidth-adjustable filter includes an operational amplifier, a first resistor, a first capacitor and a first resistor ladder circuit. The operational amplifier has a negative input terminal and a positive input terminal The first resistor is coupled to one of the input terminals of the operational amplifier. The first capacitor is coupled to the first resistor. The first resistor ladder circuit is coupled in parallel to the first resistor for changing the resistance of the first resistor so as to adjust the bandwidth of the filter.

Abstract: The present invention discloses an impedance matching circuit for facilitating impedance matching between the characteristic impedance of a cable and the input impedance at the input terminal of a receiver for data transmission comprising: a first transistor, a second transistor, a resistor, a negative feedback control circuit, a multiplexer and a reference voltage generator. When the characteristic impedance of the cable varies, the equivalent resistance of the impedance matching circuit can be kept equal to the resistance of the varied characteristic impedance of the cable by adjusting the reference voltage.