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5896066 PLL synthesizer having a reset circuit  
A PLL including a phase comparator, a VCO, and a charge pump further includes a reset circuit. The reset circuit detects whether both of the charge pump transistors are in an ON state, and if so,...
5894247 Optical PLL circuit and method of controlling the same  
An optical PLL circuit with high precision that has its simplified configuration. An optical-intensity modulator creates difference frequency information (N×Δf) by modulating a received optical...
5889435 On-chip PLL phase and jitter self-test circuit  
An ASIC includes a PLL and digital circuitry to quantize and measure phase and average maximum jitter between a system clock input to the PLL, and a PLL-generated clock signal. The system clock is...
5889437 Frequency synthesizer with low jitter noise  
An improved apparatus for combining frequencies which is capable of generating a constant frequency when an external variation is applied thereto by implementing each block using a differential...
5889440 Adaptive frequency compensation technique  
The frequency of a clocking signal is adjusted in response to fluctuations in the power supply voltage. In one embodiment, a control circuit has a plurality of clock input terminals each coupled...
5886582 Enabling clock signals with a phase locked loop (PLL) lock detect circuit  
A circuit for enabling and disabling generation of an output clock signal is disclosed. The circuit includes a PLL lock detect circuit that generates an active lock control signal when an output...
5877658 Phase locked loop  
A phase locked loop comprises a voltage controlled oscillator, a 1/n frequency demultiplier, a phase comparator, and a modulation circuit. The phase comparator is supplied with a first signal which...
5874863 Phase locked loop with fast start-up circuitry  
A phase-locked loop (PLL) circuit has a phase comparator for comparing the phases of a local clock frequency and a reference frequency to generate a control signal indicative of a direction of...
5872487 Fast frequency switching synthesizer  
A frequency synthesizer that can switch an output frequency fast and generates little spurious output is provided. This frequency synthesizer comprises a phase locked loop including a...
5872486 Wide-range fine-step vector modulator frequency synthesizer  
A frequency synthesizer comprises a voltage controlled oscillator (VCO) with an output frequency f out that is dependent on a VCO-control voltage input. A divide-by-k counter is connected to...
5870002 Phase-frequency lock detector  
A method and circuitry for detecting when a PLL achieves phase and frequency-lock to a reference frequency with minimal hardware and power dissipation are disclosed. The invention takes advantage...
5867068 Frequency synthesizer using double resolution fractional frequency division  
A fractional frequency synthesizer (100) includes a symmetrical divider (165) having an output frequency signal (135) fractionalized based on half cycles of its input frequency signal (130). The...
5861766 Multimode frequency synthesizer having high loop gain in frequency seek mode  
A frequency synthesizer has multiple modes of operation including a relatively short-duration frequency seek mode and a relatively long-duration normal mode. The synthesizer responds to a reference...
5856761 PLL frequency synthesizer using plural phase comparators and frequency dividers  
A PLL frequency synthesizer for realizing high-speed operation in a frequency synthesizer having a small channel interval Δf. There are provided n-number of phase comparators, feedback frequency...
5854576 Method and apparatus for a finely adjustable clock circuit  
A method and apparatus for generating a finely adjustable clock is accomplished by a ring oscillator, a plurality of counting circuits, and a controller. The ring oscillator generates a plurality...
5854575 Dual-loop phase-locked loop  
An integrated circuit phase-locked loop includes a phase/frequency detector, a charge pump, and a voltage-controlled oscillator (VCO) which are coupled together in series. The VCO has first and...
5847617 Variable-path-length voltage-controlled oscillator circuit  
A variable-path-length voltage-controlled oscillator circuit is provided. The oscillator circuit has a ring oscillator formed from a series of voltage-controlled inverter stages. The path length...
5847611 Fractional divided frequency synthesizer with phase error compensating circuit  
In a frequency synthesizer, a variable frequency divider divides the oscillation signal of a VCO while switching the frequency dividing ratio in accordance with an integral frequency dividing ratio...
5838203 Method and apparatus for generating waveforms using adiabatic circuitry  
A method and an apparatus for generating oscillating waveforms using adiabatic circuitry. In one embodiment, an LC oscillating circuit generates oscillating waveforms that are replenished with...
5838202 Error suppressing circuit and method therefor for a phase locked loop  
An error suppressing circuit (301) and method therefor for a phase locked loop (PLL) (300). According to one embodiment of the present invention, a transient condition, for example, a bandwidth...
5835544 Clock signal reproduction circuit and data reproduction circuit  
A clock signal reproduction circuit including an A/D conversion circuit for converting an input RF analog signal with a restricted upper limit of a frequency band into a digital signal, a digital...
5836000 Phase locked loop having automatic free running frequency adjustment  
The capture range and stability of a phase locked loop are improved by adjusting the free running frequency of a voltage controlled oscillator in response to the output signal of the phase locked...
5834980 Method and apparatus for supplying synchronization signals securing as clock signals with defined phase relationships  
A method and apparatus for recovering the time base of signals which change at periodic intervals is disclosed. The apparatus comprises gated voltage controlled oscillators (GVCO) that are...
5831481 Phase lock loop circuit having a broad loop band and small step frequency  
A phase lock loop circuit includes an oscillator, a digital mixer, a comparator, a loop amplifier, and a low-pass filter. The oscillator has an oscillation frequency controlled by a control...
5828253 Phase synchronization system which reduces power consumption and high frequency noise  
The invention provides a phase synchronization system which stops, when an input of a phase reference signal from the outside stops, oscillation of a voltage-controlled oscillator to achieve...
5825226 Delay equalization apparatus and method  
A delay equalization circuit for minimizing the static phase error in a PLL is provided. The delay equalization circuit includes an external clock signal variable delay path, and an element for...
5825253 Phase-locked-loop with noise shaper  
A phase lock loop wherein the reference clock is divided by a variable divider which is capable of dividing the reference clock by a divider ratio of 2, 3, 4, . . . or M depending on the value of a...
5821816 Integer division variable frequency synthesis apparatus and method  
A variable frequency synthesis apparatus and method use a phase prediction signal to enable integer division in the feedback path of a phase-lock-loop to provide an output signal at a rational...
5821817 Fast-locking low-noise phase-locked loop  
A phase-locked-loop device for generating an output signal of frequency Fo, n phase-lock with an input signal of frequency Fi, where Fo=N(Fi/M). The invention reduces noise and provides...
5818303 Fractional N-frequency synthesizer and spurious signal cancel circuit  
A fractional N-frequency synthesizer includes an accumulator outputting an output value, and a spurious signal cancel circuit. The spurious signal cancel circuit includes a pulse forming circuit,...
5818304 Phase-locked loop  
A phase-locked loop (PLL) includes a voltage controlled oscillator (VCO), a charge pump, a phase detector and a frequency detector. The phase detector detects the phase difference between an...
5815540 Semiconductor integrated circuit device including PLL circuit  
A semiconductor integrated circuit device including input and output registers, a data-processing circuit block disposed between the registers, a first PLL circuit for supplying a first output...
5809097 Low jitter phase detector for phase locked loops  
A digital phase detector which generates low jitter when the phase-locked-loop is in lock. A delay line, combined with an UP/DOWN phase detector causes substantial overlap in the UP and DOWN...
5805024 Phase lock loop system including a primary phase lock loop apparatus and a high order phase lock loop apparatus  
A phase lock loop system includes: a phase detecting circuit which operates on the basis of a signal waveform; a current output circuit for generating a current value from a phase difference...
5805002 Slow transition time phase frequency detector and method  
A phase frequency detection circuit and method in a phase lock loop circuit uses delay circuits to limit the period of expression of up and down signals which adjust the output frequency of a...
5796311 Phase-locked loop circuit  
A PLL circuit has a feedback loop including a plurality of feedback circuits in parallel and a combining circuit. The feedback circuits receives an output signal of the PLL circuit and produce...
5789985 Frequency multiplying device and digitally-controlled oscillator  
A frequency multiplying device which multiplies the frequency of an externally-supplied reference signal PREF includes a digitally-controlled oscillation circuit, which includes a ring oscillator...
5789988 Clock recovery circuit for QAM demodulator  
In a clock recovery circuit in a demodulator of a multi-level quadrature amplitude modulation (QAM) system, an analog/digital (A/D) converter performs an A/D conversion upon a coherent-detected...
5786732 Phase locked loop circuitry including a multiple frequency output voltage controlled oscillator circuit  
A phase locked loop including a comparator, a VCO controller, and a VCO having a multi-stage oscillator portion and a combinational logic portion. The comparator is responsive to an input clock and...
5783972 Power saving PLL circuit  
A phase lock loop includes a voltage controlled oscillator (VCO), a phase comparator for comparing the phases of the output of the VCO and a reference signal, a charge pump circuit, including a...
5784122 Chroma lock detector  
A chroma lock detector circuit monitors charge pump control signals within a phase-lock loop to determine when two input signals to the phase-lock loop are locked together in phase and generates an...
5774511 Processor clock circuit  
Within a microprocessor, multiple synchronous clock signals of arbitrary integer and non-integer ratios are produced with conventional digital divider circuitry. The various integer and non-integer...
5774022 Digital clock recovery loop  
A communications system including a clock recovery circuit that extracts a clock signal from incoming digital data, the clock recovery circuit including a voltage controlled oscillator having a...
5770976 Local clock duty cycle independent phase detector and method of operation thereof  
A phase detector for a phase-locked loop ("PLL") circuit under control of a local oscillating clock ("LOSC") signal and a method of operation thereof. The phase detector includes: (1) a first...
5767713 Phase locked loop having integration gain reduction  
A non-linear integrated phase locked loop circuit includes a phase detector for receiving a data signal and a clock pulse and for outputting a pump-up signal and a pump-down signal, a pulse divider...
5764111 Voltage controlled ring oscillator frequency multiplier  
A voltage controlled ring oscillator (10) integrated with a phase locked loop (101) using CMOS technology. The ring oscillator (10) provides a frequency multiplied harmonic output frequency (42) at...
5764712 Phase locked loop circuit having automatic range setting logic  
A method for setting a locking frequency operating range of the phase locked loop (PLL) circuit and a phase locked loop (PLL) circuit are provided with range select logic for detecting an unknown...
5760653 Phase-locked loop for clock recovery  
A PLL circuit includes a sampling pulse generator and a loop circuit using a sample and hold circuit as a phase detector. The sampling pulse generator generates a sampling pulse signal at each...
5761255 Edge-synchronized clock recovery unit  
A clock recovery unit for recovering a clock embedded in a data communication is disclosed. The clock recovery unit includes an oscillator (50) operating at a frequency close to that of the clock...
5754080 Single-edge triggered phase detector  
A single-edge triggered phase detector which provides high speed phase detection. The phase detector works on only a single edge of the clock and data signal, which can be either the rising or...