Abstract: A phase locked loop (PLL) with a loop bandwidth calibration circuit is provided. The mixed-mode PLL comprises an analog phase correction path, a digital frequency correction path, a calibration current source, and a loop bandwidth calibration circuit. The analog phase correction path comprises a linear phase correction unit (LPCU). The digital frequency correction path comprises a digital integral path circuit. The calibration current source is coupled to the LPCU. The loop bandwidth calibration circuit is coupled to a frequency divider and coupled between the input and output of the PLL. The loop bandwidth calibration circuit operates after the calibration current source injects a calibration current into the LPCU.

Abstract: A signal processing circuit includes: a first operation circuit for receiving a phase component of an input signal, and generating an adjusted phase component and at least one weighting factor according to the phase component of the input signal; a second operation circuit, coupled to the first operation circuit, for receiving the adjusted phase component and converting the adjusted phase component into a frequency component corresponding to the adjusted phase component; a third operation circuit, coupled to the first operation circuit, for receiving an amplitude component of the input signal, and adjusting the amplitude component according to the at least one weighting factor to generate an adjusted amplitude component; and a fourth operation circuit, coupled to the second operation circuit and the third operation circuit, for generating an output signal according to the frequency component and the adjusted amplitude component.

Abstract: A mixed-mode PLL is disclosed. The mixed-mode PLL comprises a digital sigma-delta modulator, a low pass filter, and a digital controlled oscillator. The digital sigma-delta modulator receives a fractional bit signal. The low pass filter is coupled to the digital sigma-delta modulator. The low pass filter receives an output signal of the digital sigma-delta modulator and converts the output signal to an analog control signal. The digital controlled oscillator comprises a varactor dynamically coupled to the low pass filter and receiving the analog control signal.

Abstract: For decreasing errors within an analog phase-locked loop, an all-digital phase-locked loop (ADPLL) with digital components and digital operations is used. The ADPLL may also be used for direct frequency modulation (DFM). By defining a proportional path gain of an ADPLL by a bandwidth and a reference frequency of the ADPLL, by a TDC gain, a DCO gain, a dividing ratio of a frequency divider, a gain of an amplifier or a combination thereof, the gain of the amplifier may be adjusted so that an optimal loop bandwidth of the ADPLL may be well calibrated. For achieving the aim of entirely digital of the ADPLL, the gains of the TDC and the DCO may be further adjusted in a digital manner.

Abstract: A mixed-mode PLL is disclosed. The mixed-mode PLL comprises an analog phase correction path and a digital frequency correction path. The analog phase correction path comprises a linear phase correction unit (LPCU). The digital frequency correction path comprises a digital integral path circuit.

Abstract: A phase-locked loop circuit, including: an operating circuit for detecting a difference between a reference signal and a feedback oscillating signal to generate a detected result, and generating a first control signal according to the detected result, an auxiliary circuit for generating a second control signal that is asynchronous with the first control signal, and a controllable oscillator coupled to the operating circuit and the auxiliary circuit for generating an output oscillating signal according to the first control signal and the second control signal, wherein the feedback oscillating signal is derived from the output oscillating signal.

Abstract: A digital-controlled oscillator (DCO) is utilized in an all-digital phase-locked loop for eliminating frequency discontinuities. The DCO includes a tank module and a negative gm cell. The tank module comprises a plurality of cells, at least a portion of the cells comprising a first tracking set and a second tracking set for respectively handling an odd bit or an even bit. The odd bit and the even bit are related to an integer signal, a fractional signal or a combination thereof, the fractional signal is indicated by a primary voltage inputted to the DCO. With the DCO, frequency discontinuities and undesired spurs are eliminated.

Abstract: A clock recovering circuit for generating an output clock locked to an analog input signal includes: a phase detection unit for receiving the analog input signal and the feedback clock for generating a phase error signal according to the analog input signal and the feedback clock; a loop filter coupled to the phase detector for filtering the phase error signal and generating a control signal; a numerically controlled oscillator (NCO) coupled to the loop filter for generating a first clock and an index signal according to the control signal; a delay locked loop (DLL) coupled to the NCO for receiving the first clock and generating a plurality of second clocks; and a multiplexer coupled to the NCO and the DLL for selecting one of the second clocks as the output clock according to the index signal.

Abstract: A vernier phase error detection method is provided. The method comprises providing a first signal having a first cycle T1, wherein T1=1/N T; providing a second signal having a second cycle T2, wherein T2=1/M T; aligning a rising edge of the second signal with a rising edge of the first signal; when a second data sampled by the second signal is different from a first data sampled by the first signal at the Xth second cycle, a phase error Ø is evaluated by the following equation: Ø=(N/2?X)*T1.

Abstract: A loop latency compensated phase-locked loop (PLL). The loop latency compensated PLL comprises an ADC, a phase detector, a loop filter and a VCO. The ADC receives an analog input signal and an output clock to generate a digital signal. The phase detector receives the digital signal to generate an estimated phase error. The loop filter receives the estimated phase error to generate a latency compensated phase error output signal with a phase assigned by a sign-bit of the received estimated phase error. The VCO generates the output clock in response to the latency compensated phase error output signal and feeds the output clock back to the ADC.

Abstract: A phase-locked loop circuit. The phase-locked loop circuit comprises a phase detector, a proportional charge pump, a decimator, an integral charge pimp, and a voltage-controlled oscillator. The phase detector obtains an phase error information according to a phase difference between a reference signal and a clock signal input to the phase detector. The proportional charge pump coupled to the phase detector generates a first voltage according to the phase error information. The decimator generates a decimated version of the phase error information by a decimation factor of N. The integral charge pump generates a second voltage according to the decimated version of the phase error information. The voltage-controlled oscillator generating the clock signal according to a combination of the first and second voltages.

Abstract: A delay circuit includes a first reference delay module, a second reference delay module and a first delay module. The first reference delay module delays a reference signal and generates a first reference delayed signal, and the second reference delay module delays the reference signal and generates a second reference delayed signal according to a reference control signal and the first reference delayed signal. The first delay module delays a first input signal and generates a first output signal according to a first control signal and the second reference delayed signal.

Abstract: A charge pump-based frequency modulator is provided. The charge pump-based frequency modulator comprises an analog phase correction path comprising a varactor and a charge pump. The varactor is coupled to an output of the charge pump-based frequency modulator. The charge pump is coupled to a node between the varactor and the output and receives a signal containing the modulated data.

Abstract: A phase-locked loop circuit. The phase-locked loop circuit comprises a phase detector, a proportional charge pump, a decimator, an integral charge pimp, and a voltage-controlled oscillator. The phase detector obtains an phase error information according to a phase difference between a reference signal and a clock signal input to the phase detector. The proportional charge pump coupled to the phase detector generates a first voltage according to the phase error information. The decimator generates a decimated version of the phase error information by a decimation factor of N. The integral charge pump generates a second voltage according to the decimated version of the phase error information. The voltage-controlled oscillator generating the clock signal according to a combination of the first and second voltages.

Abstract: A mixed-mode PLL is disclosed. The mixed-mode PLL comprises an analog phase correction path and a digital frequency correction path. The analog phase correction path comprises a linear phase correction unit (LPCU). The digital frequency correction path comprises a digital integral path circuit.

Abstract: Clock generators are provided. A phase locked loop generates an output clock, a delay line is coupled to an input of the phase locked loop, and a modulation unit integrates an input signal with a constant level to generate a modulation signal controlling the delay line, thereby modulating a phase of a first input clock of the phase locked loop, such that frequency of the output clock is locked at a desired frequency.

Abstract: Spread spectrum clock generators. A phase lock loop generates an output clock according to a first input clock and a second input clock, a delay line is coupled between the first input clock and the phase lock loop. A modulation unit provides a modulation signal to control the delay line thereby modulating phase of the first input clock, such that frequency of the output clock generated by the phase lock loop varies periodically.

Abstract: A digital-controlled oscillator (DCO) is utilized in an all-digital phase-locked loop for eliminating frequency discontinuities. The DCO includes a tank module and a negative gm cell. The tank module comprises a plurality of cells, at least a portion of the cells comprising a first tracking set and a second tracking set for respectively handling an odd bit or an even bit. The odd bit and the even bit are related to an integer signal, a fractional signal or a combination thereof, the fractional signal is indicated by a primary voltage inputted to the DCO. With the DCO, frequency discontinuities and undesired spurs are eliminated.

Abstract: For decreasing errors within an analog phase-locked loop, an all-digital phase-locked loop (ADPLL) with digital components and digital operations is used. The ADPLL may also be used for direct frequency modulation (DFM). By defining a proportional path gain of an ADPLL by a bandwidth and a reference frequency of the ADPLL, by a TDC gain, a DCO gain, a dividing ratio of a frequency divider, a gain of an amplifier or a combination thereof, the gain of the amplifier may be adjusted so that an optimal loop bandwidth of the ADPLL may be well calibrated. For achieving the aim of entirely digital of the ADPLL, the gains of the TDC and the DCO may be further adjusted in a digital manner.

Abstract: A circuit for controlling a mixed mode controlled oscillator. The circuit comprises a charge pump, and a digital loop filter. The charge pump is coupled to the mixed mode controlled oscillator. The charge pump receives an up/down signal and sends a current signal to the mixed mode controlled oscillator. The digital loop filter receives the up/down signal and generates a digital code signal to the mixed mode controlled oscillator. An output frequency of the mixed mode controlled oscillator is controlled by the current signal and the digital code signal.