201results about "Phase shifter" patented technology

The invention relates to a phase-interpolation circuit and a phase-interpolation signal generating circuit applying the phase-interpolation circuit. The phase-interpolation circuit can avoid short-circuit current effectively. In addition, an inter-phase signal can be interpolated between the rising edge and the falling edge of the clock pulse. The phase-interpolation signal generating device can generate multiphase clock signals which not only have linearly distributed phases but also maintain good 50% duty cycle of the multiphase clock signals.

A system and method of conditioning differential clock signals iteratively adjusts the duty cycles and phases of the clock signals. The duty cycles of the clock signals are adjusted by comparing respective voltage corresponding to the duty cycles of respective clock signals in each of the differential pairs. The result of the comparison is used to adjust the duty cycles of the clock signal until the magnitudes of the voltages are substantially equal. The phases of the clock signals are adjusted by selecting two sets of two clock signals each that are assigned relative phases that differ from each other by the same amount. The selected sets of clock signals are processed so that the duty cycles of resulting signals correspond to the phases of the clock signals. The duty cycle of these signals is measured as described above and used to adjust the phases of the clock signals.

The system and method generates two clock signals, one with a 2 ns delay with respect to the other, from a single PLL to enable a RGMII.

Circuits and methods for generating multi-phase clock signals using digitally-controlled hierarchical delay units (HDs) are provided. A plurality of serially-coupled HDs outputs clock signals that are phase-shifted relative to a reference clock signal. Each HD includes either one or two variable delay lines that provide coarse phase adjustment of an associated input signal. Each HD also includes one or more phase mixers that provide fine phase adjustment of the input signal.

The invention includes a novel differentiator cell, a novel resample unit cell, and precision synchronization circuitry to ensure proper timing of the circuits and systems at the anticipated ultra-high speed of operation. The novel differentiator cell includes circuitry for combining a carry input signal, a data bit signal and the output signal of a NOT cell and applying the signals as distinct and separate pulses to the input of a toggle flip-flop (TFF) for producing an asynchronous carry output and a clocked data output. The novel differentiator cells can be interconnected to form a multi-bit differentiator circuit using appropriate delay and synchronization circuitry to compensate for delays in producing the carry output of each cell which is applied to a succeeding cell. The novel resample cell includes a non-destructive reset-set flip-flop (RSN) designed to receive a data bit, at its set input, at a slow clock rate, which data is repeatedly read out of the RSN at a fast clock rate, until the RSN is reset. The novel differentiator and resampler cells can be interconnected, for example, to form the differentiator and up-sampling sections of a digital interpolation filter (DIF). Also, the relative clocking of bit slices (columns) in such a DIF may be achieved by using the fast clock signal to synchronize the slow clock which controls data entry. The circuits of the invention can be advantageously implemented with Josephson Junctions in rapid-single-flux-quantum (RSFQ) logic.

Integrated circuit delay devices include a digital delay line that is configured to provide a percent-of-clock period delay to a timing signal accepted at an enabled one of a plurality of injection ports thereof. The digital delay line may be responsive to an injection control signal having a value that sets a length of the delay by specifying a location of the enabled one of the plurality of injection ports, with the end of the delay line being a fixed output port. A delay line control circuit is also provided that is responsive to a clock signal having a period from which the percent-of-clock period delay is preferably measured. The delay line control circuit is configured to generate the injection control signal by counting multiple cycles of a high frequency ring oscillator signal having a period less than, and typically substantially less than, the clock period, over a time interval having a duration greater than, and typically substantially greater than, the clock period. The ring oscillator signal may be generated by a ring oscillator having a relatively small number of stages and the time interval may be sufficiently long so that a large number of cycles of the ring oscillator signal may be counted over many periods of the clock signal.

A programmable logic device has programmable phase-shifting circuitry. The phase-shifting circuitry is used to generate a set of skewed clock signals that is used to adjust the relative timing of device elements in a circuit synthesized in the programmable logic device. By suitably adjusting the relative timing of the device elements, the circuit critical path lengths are effectively reduced leading to improved circuit frequency performance. Algorithms are provided for establishing clock skew values that lead to improved circuit performance. The algorithms are incorporated in computer aided design tools to enable automatic optimization of circuit designs.

So as to generate multiple output signals whose phases are evenly spaced about 360 degrees, and having a frequency equal to that of an input signal, a phase multiplier circuit includes three or more instances of a phase multiplier subcircuit and additional circuitry configured in a negative feedback loop. Each phase multiplier subcircuit includes a difference circuit, a loop filter transistor, and a voltage-controlled delay circuit. The difference circuit converts to a phase current a delay from an input signal to the delay circuit to an output signal from the delay circuit, and subtracts from the phase current a bias current proportional to the smallest positive delay from the output signal with the largest phase to the output signal with the smallest phase. The subtracted current is integrated by the loop filter transistor, and steady-state operation is achieved when for each phase multiplier subcircuit, the bias current is equal to the phase current. Evenly spaced phases of the output signals about 360 degrees are achieved when the delay to phase current gain and delay to bias current gain are substantially equal.