摘要:
Methods and apparatus are provided for equalizing a received signal. A received signal is equalized by updating one or more equalization parameters; and discarding the updated equalization parameters if one or more predefined qualifier conditions are detected during the equalizing step. The received signal can optionally be equalized using the updated equalization parameters if the predefined qualifier conditions are not detected during the equalizing step. The updated equalization parameters can optionally be stored if the one or more predefined qualifier conditions are not detected during the equalizing step.
摘要:
In described embodiments, a clock alignment system with a digital bang-bang phase detector (BBPD) employs digitally implemented hysteresis. A first BBPD is employed for a phase control loop that compares the phases from two different clock domain sources, where one clock domain source is used as a reference clock for the phase control loop. A second BBPD with delayed reference clock is employed to resolve ambiguous phase relations seen by the first BBPD. An initial state of a BBPD vector, defined as a vector of current values of the first BBPD and the second BBPD, is examined. Based on the initial and subsequent states of the BBPD vector, the non-reference clock is permitted to naturally move to a lock state through action of the phase control loop, or forced to have its phase rotate clockwise or counterclockwise to reach the lock state.
摘要:
Methods and apparatus are provided for evaluating the eye margin of a communications device using a data eye monitor. The quality of a data eye associated with a signal is evaluated by sampling the signal for a plurality of different phases; evaluating the samples to evaluate one or more of a height and width of the data eye; and determining whether the one or more of the height and width satisfy one or more predefined criteria. One or more parameters of the communications device can optionally be adjusted if the communications device does not satisfy the one or more predefined criteria. The communications device can optionally be assigned to a quality category based on the evaluation. A phase offset between a first clock signal used to sample the signal and one or more clocks used to sample data is reduced.
摘要:
Disclosed is a circuit for adjusting a voltage supplied to an IC by a power supply circuit that produces a regulated-output voltage based on an output-control signal generated by a resistive voltage divider. The circuit includes a PVT detector configured to generate an interface control signal and an interface circuit (i) connected to PVT detector and to the resistive voltage divider and (ii) configured to adjust its resistance in response to the interface control signal. Adjusting the resistance of the interface circuit causes the voltage of the output-control signal to be adjusted, thus causing the power supply circuit to adjust the regulated output voltage.
摘要:
A voltage controlled delay loop and method are disclosed for clock and data recovery applications. The voltage controlled delay loop generates clock signals having similar frequency and different phases. The voltage controlled delay loop comprises a plurality of delay elements; and an input that selectively injects a reference clock into any one of the plurality of delay elements. The plurality of delay elements are connected in series, such as in a loop. In one exemplary implementation, each delay element has an associated multiplexer that selects one of the reference clock and a signal from a previous delay element.
摘要:
A compensation circuit for reducing power consumption in at least one digital circuit includes a first sample circuit connected to a first supply voltage, a second sample circuit connected to a second supply voltage, and a controller connected to the first and second sample circuits. The first and second sample circuits are substantially functionally equivalent to one another but optimized for different regions of operation within a specified range of PVT conditions. The controller is operative to receive respective output signals from the first and second sample circuits, to monitor a functionality of the second sample circuit relative to the first sample circuit, and to adjust a level of the second supply voltage to ensure correct operation of the second sample circuit throughout the specified range of PVT conditions. The digital circuit is operative from the second supply voltage.
摘要:
A system for improving the attenuation of an undesired signal found in a differential signal path through the use of inductive coupling. The system includes a primary inductor, a secondary inductor, and a filter. The primary inductor and the secondary inductor operably couple an input differential signal pair to an output differential signal pair, and the filter attenuates an undesired signal in the output differential signal pair.
摘要:
Disclosed is a circuit for adjusting a voltage supplied to an IC by a power supply circuit that produces a regulated-output voltage based on an output-control signal generated by a resistive voltage divider. The circuit includes a PVT detector configured to generate an interface control signal and an interface circuit (i) connected to PVT detector and to the resistive voltage divider and (ii) configured to adjust its resistance in response to the interface control signal. Adjusting the resistance of the interface circuit causes the voltage of the output-control signal to be adjusted, thus causing the power supply circuit to adjust the regulated output voltage.
摘要:
The various embodiments of the invention provide an apparatus, system and method of asynchronous testing a serializer and deserializer data communication apparatus (SERDES) for determining frequency and phase locking to pseudo asynchronous input data having a continual phase offset. An exemplary apparatus includes a data sampler adapted to sample input serial data and to provide output data; a controlled tap delay with a selected tap having a phase offset from the input serial data, in which the selected tap is selectively coupleable to the data sampler to provide pseudo asynchronous input serial data; a first variable delay control adapted to delay a reference frequency provided to the controlled tap delay in response to the pseudo asynchronous input serial data; and a second delay control adapted to adjust the plurality of taps in response to the pseudo asynchronous input serial data. In additional embodiments, the pseudo asynchronous input serial data is provided from an interpolated phase from at least two selected taps.
摘要:
Disclosed is a circuit that adjusts a characteristic of a signal transmitted from a transmitter to a receiver over a communication channel (e.g., a wire, a backplane, etc.). The circuit includes a latch that receives the signal at a predetermined point in the circuit and samples a voltage of the signal many times after a threshold voltage is applied to the latch. The circuit also includes a processor that determines the characteristic of the signal when the sampled voltages indicate a transition point and that adjusts the threshold voltage when the sampled voltages do not indicate a transition point. The processor adjusts the characteristic of the signal by adjusting at least one of a current and a voltage of the transmitter when the characteristic of the signal is outside a predetermined range.