Abstract: A one-wire communication bus for transferring a sequence of digital data from a transmitter to a receiver includes (a) an ECDD signal modulation circuit to create an electrical pulse train wherein each pulse's edge is used as clock signal and each pulse's duty cycle is used to represent digital value of zero and one; (b) an ECDD signal demodulation circuit to receive the ECDD pulse train using a group of sampling cells and to decode the sampled results using a majority voting circuit; (c) an electrical connection between a transmitter wherein the ECDD signal modulation circuit resides and a receiver wherein the ECDD signal demodulation circuit resides. Said ECDD signal is sent from the transmitter to the receiver through the electrical connection. Methods of creating the ECDD pulse train in the transmitter and decoding the ECDD pulse train in the receiver are also disclosed.

Abstract: A Time-Average-Frequency direct period synthesizer is used to improve crystal-less frequency generator's frequency stability. It includes (a) a temperature sensor circuit to compensate temperature-induced frequency instability; (b) a voltage sensor circuit to compensate voltage-induced frequency instability; (c) a calibration circuit to correct manufacture-related frequency error; (d) a frequency control word update circuit to receive the temperature- and voltage-related frequency adjustments, and the calibration-related adjustment, to generate the corresponding frequency control word in a predetermined schedule; (f) a Time-Average-Frequency direct period synthesizer to receive said frequency control word in the predetermined schedule and produce a clock signal with a frequency that is stable and accurate by counteracting the frequency variation caused by crystal-less oscillators' temperature and voltage dependence and correcting the frequency error introduced in manufacture process.

Abstract: A method of reducing a water-wave noise for an analog to digital conversion includes performing sampling on an analog input signal; determining whether the analog input signal is interfered with by a periodic noise such that a water wave is generated; and executing one or both of the following steps when the analog input signal is interfered with by the periodic noise: adjusting a sampling frequency of the ADC, and adjusting a noise frequency of the periodic noise.

Abstract: An open loop clock divider circuit includes (a) a first divider configured to receive an incoming clock signal and output a first divided clock signal, (b) a flying-adder synthesizer configured to fractionally divide the first divided clock signal and output a fractionally divided clock signal, and (c) a second divider configured to receive the fractionally divided clock signal and output a second divided clock signal. The open loop clock divider circuit advantageously provides a fractional divider in which there is no feedback loop between the source frequency (fs) and the destination frequency (fd). Methods of generating a divided clock signal involving the open loop clock divider circuit are also disclosed.

Abstract: A method of reducing a water-wave noise for an analog to digital conversion includes performing sampling on an analog input signal; determining whether the analog input signal is interfered with by a periodic noise such that a water wave is generated; and executing one or both of the following steps when the analog input signal is interfered with by the periodic noise: adjusting a sampling frequency of the ADC, and adjusting a noise frequency of the periodic noise.

Abstract: A clock data recovery circuit includes a binary phase detector configured to receive an incoming data signal and a recovered clock, and output a phase offset signal and recovered data; a digital loop control circuit configured to receive the phase offset signal and output a control signal; and a digital frequency generator configured to receive the control signal and output the recovered clock. A method of clock recovery includes generating a digital phase offset signal from incoming data and feedback clock signals; generating a clock frequency control signal from the phase offset signal; generating a recovered clock in response to the control signal; slowing down the recovered clock when the digital phase offset signal has a first binary state; speeding up the recovered clock when the digital phase offset signal has a second binary state; and holding the recovered clock when the digital phase offset signal has a third binary state.

Abstract: A phase locked loop including a flying-adder divider circuit configured to receive phases of a periodic signal from a frequency generator and output a feedback signal to a phase detector, and a method of generating a periodic signal using such a flying-adder circuit, are disclosed. The flying-adder divider circuit generally includes a flying-adder and one or two divide-by-N dividers. The flying-adder receives K phases of the periodic signal, where K is an integer of at least 2, and generates a divided periodic signal from the K phases. The phase locked loop may include flying-adder divider circuits inside and/or outside the loop.

Abstract: One of the advantages of direct frequency synthesis technique (e.g., flying-adder architecture) is its capability of generating arbitrary frequency by utilizing the time-average-frequency concept. In the clock output of the direct frequency synthesizer, instead of one type of cycle, there are two types of cycles. Unlike the conventional one-type-cycle clock wherein clock energy is concentrated at its designed frequency, Time-Average-Frequency based clock spreads some of its energy into spurious tones, which could be harmful to certain applications. The spurious tones are caused by the periodic carry sequence generated from a fractional part accumulator inside the frequency synthesizer. The invention suggests a method and an apparatus to break this periodicity and convert the spurious tones into broadband noise.

Abstract: A lock detector for a phase lock loop (PLL) includes: first and second pulse width extenders, performing pulse width extension on first and second pulses for generating third and fourth pulses, respectively; first and second delay circuits, delaying the third and the fourth pulses into first and second sampling clocks, respectively; and a cross-sampling circuit, sampling the third pulse based on the second sampling clock and sampling the fourth pulse based on the first sampling clock to indicate whether the PLL is locked.

Abstract: Synchronous circuitry for processing digital data in which the data are filtered to compensate for expected jitter in time-average frequency clock signals. Time-average frequency synthesis circuitry generates internal clock signals of a desired frequency, for example as based on a recovered clock signal from an input data stream, in a manner in which not all periods of the clock signal are of uniform duration. A jitter precorrection filter is inserted into the data path to apply a variable delay to pre-correct for distortion caused by jitter in the clock cycle. In embodiments of the invention using a flying-adder architecture to generate the clock signal, coefficients of the digital filer realizing the jitter precorrection filter are calculated according to the currently-selected oscillator phase and according to a fractional portion of a digital frequency control word.

Abstract: This invention uses a flying adder frequency synthesis circuit to provide the required frequency adjustments to accommodate the varying encoding density of a MPEG2 video data stream. This invention adjusts the local clock based on the information extracted from the program clock reference signal in the incoming data. This invention replaces an external or internal voltage-controlled crystal oscillator using a phase locked loop circuit on the video processing integrated circuit.

Abstract: To make Flying-Adder architecture even more powerful, a new concept, time-average-frequency, is incorporated into the clock generation circuitry. This is a fundamental breakthrough since it attacks the clock generation problem from its root: how is the clock signal used in real systems? By investigating from this direction, a much more powerful architecture, fixed-VCO-Flying-Adder architecture, is created. Furthermore, based on fixed-VCO-Flying-Adder frequency synthesizer and time-average-frequency, a new type of component called Digital-to-Frequency Converter (DFC) is born.

Abstract: To make Flying-Adder architecture even more powerful, a new concept, time-average-frequency, is incorporated into the clock generation circuitry. This is a fundamental breakthrough since it attacks the clock generation problem from its root: how is the clock signal used in real systems? By investigating from this direction, a much more powerful architecture, fixed-VCO-Flying-Adder architecture, is created. Furthermore, based on fixed-VCO-Flying-Adder frequency synthesizer and time-average-frequency, a new type of component called Digital-to-Frequency Converter (DFC) is born.

Abstract: A lock detector for a phase lock loop (PLL) includes: first and second pulse width extenders, performing pulse width extension on first and second pulses for generating third and fourth pulses, respectively; first and second delay circuits, delaying the third and the fourth pulses into first and second sampling clocks, respectively; and a cross-sampling circuit, sampling the third pulse based on the second sampling clock and sampling the fourth pulse based on the first sampling clock to indicate whether the PLL is locked.

Abstract: A Xiu-accumulator circuit including N cascaded adders is provided. Each adder includes two registers, wherein one register stores an addition result information and the other register stores a carry-in information. Respective addition result information from respective adder is further fed back to itself for accumulation. The carry-in information outputted from a previous stage adder is fed to a next stage adder at a next clock cycle. After N clock cycles, the carry-in information outputted from the first stage adder is fed to the last stage adder.

Abstract: A digital video system (2) is disclosed, in which an analog input video signal is sampled at an optimum sample phase (Pnc), and converted to a digital datastream for display. A phase-locked loop (12) generates a plurality of sample clock phases. One of the sample clock phases (Pnc) is applied to an analog-to-digital converter (10), which digitizes the analog input video signal accordingly. Phase alignment circuitry (20) is provided that includes three sample-and-hold circuits (22b, 22c, 22a) that sample the analog input video signal, in parallel with the analog-to-digital converter (10), at times before, at, and after the current sample clock phase used by the analog-to-digital converter (10). The earlier and later sampled voltages are compared against the current sampled voltages to generate difference voltages that are each compared against a threshold voltage (Vthr).

Abstract: Synchronous circuitry for processing digital data in which the data are filtered to compensate for expected jitter in time-average frequency clock signals. Time-average frequency synthesis circuitry generates internal clock signals of a desired frequency, for example as based on a recovered clock signal from an input data stream, in a manner in which not all periods of the clock signal are of uniform duration. A jitter precorrection filter is inserted into the data path to apply a variable delay to pre-correct for distortion caused by jitter in the clock cycle. In embodiments of the invention using a flying-adder architecture to generate the clock signal, coefficients of the digital filer realizing the jitter precorrection filter are calculated according to the currently-selected oscillator phase and according to a fractional portion of a digital frequency control word.

Abstract: An apparatus employing control words to present a synthesized output signal having an output frequency and a delay with respect to an input signal includes: (a) A multiplexer receiving the input signal and having an output and an address input. (b) An output unit generates the output signal in response to a drive signal from the multiplexer. (c) A first register coupled with the multiplexer output. (d) A second register coupled with the multiplexer and the first register. The first register responds to a multiplexer output signal to provide a first control signal to the second register based upon the control words. The second register responds to the multiplexer output signal to provide a second control signal to the address input based upon the first control signal and the control words. The multiplexer presents the drive signal in response to the second control signal.

Abstract: A method and apparatus for adjusting to a frame rate. The method displays the video frames with varying rates. The method comprising the steps of detecting a change in the frame rate, calculating the FREQ of the frame, adjusting the phase-locked loop utilizing the calculated FREQ, and utilizing the adjusted phase-locked loop output as the pixel clock to display the frame.

Abstract: A circuit for, and method of, generating a spread-spectrum clock signal. In one embodiment, the circuit includes: (a) a modulator configured to generate a modulated control value, and (b) a frequency synthesizer coupled to the modulator and configured to generate a spread-spectrum clock signal based on a variation of the modulated control value, the frequency synthesizer having a directly-derivable frequency response output.