Disclosed is a device for detecting the margin of a circuit operating at an operating speed. The device includes: a signal generating circuit generating an input signal including predetermined data; a first adjustable delay circuit delaying the input signal by a first delay amount and thereby generating a delayed input signal; a circuit under test performing a predetermined operation based on a predetermined operation timing and thereby generating a to-be-tested signal according to the delayed input signal; a second adjustable delay circuit delaying the to-be-tested signal by a second delay amount and thereby generating a delayed to-be-tested signal; a comparison circuit comparing the data included in the delayed to-be-tested signal with the predetermined data based on the predetermined operation timing and thereby generating a comparison result; and a calibration circuit determining whether the circuit under test passes a speed test according to the comparison result.

Disclosed is a device for detecting the margin of a circuit operating at an operating speed. The device includes: a signal generating circuit generating an input signal including predetermined data; a first adjustable delay circuit delaying the input signal by a first delay amount and thereby generating a delayed input signal; a circuit under test performing a predetermined operation based on a predetermined operation timing and thereby generating a to-be-tested signal according to the delayed input signal; a second adjustable delay circuit delaying the to-be-tested signal by a second delay amount and thereby generating a delayed to-be-tested signal; a comparison circuit comparing the data included in the delayed to-be-tested signal with the predetermined data based on the predetermined operation timing and thereby generating a comparison result; and a calibration circuit determining whether the circuit under test passes a speed test according to the comparison result.

A fractional sampling-rate converter includes a first-in first-out (FIFO) buffer, a write logic, a read logic and a fractional interpolator. The write logic is designed to write input data samples into the FIFO at a first rate. The fractional interpolator is coupled to receive the input data samples from the FIFO and is designed to generate corresponding interpolated data samples as an output of the fractional sampling-rate converter at a second rate. The read logic is designed to cause input data samples in the FIFO buffer to be transferred to the fractional interpolator. A ratio of the second rate and the first rate is a fractional number greater than one.

A fractional sampling-rate converter includes a first-in first-out (FIFO) buffer, a write logic, a read logic and a fractional interpolator. The write logic is designed to write input data samples into the FIFO at a first rate. The fractional interpolator is coupled to receive the input data samples from the FIFO and is designed to generate corresponding interpolated data samples as an output of the fractional sampling-rate converter at a second rate. The read logic is designed to cause input data samples in the FIFO buffer to be transferred to the fractional interpolator. A ratio of the second rate and the first rate is a fractional number greater than one.

A phase and frequency control circuit may be provided. The phase and frequency control circuit may include a division circuit configured to generate a plurality of divided signals by dividing an input signal. The phase and frequency control circuit may include a timing control circuit configured to generate a plurality of timing control signals by sampling the plurality of divided signals according to a phase control code and a sampling reference signal.

A communication system comprising n transmitters and a receiver, where n is an integer of at least 2, each of said n transmitters comprising a light source and an encoder such that each transmitter is adapted to output an encoded pulse of light, said receiver comprising a first element, the system further comprising a timing circuit, the timing circuit being configured to synchronise the encoded pulses output by the transmitters such that interference between a light pulse sent from the first transmitter and a light pulse from the second transmitter, interfere at the first element, each transmitter further comprising a suppressing element adapted to stop light exiting one of the transmitters such that the system is switchable between a first operation mode where two transmitters output encoded pulses and where both pulses interfere at the interference element and a second mode of operation where just one transmitter transmits light pulses to said receiver, the suppressing element being controlled to stop light exiting the other transmitter.

A phase interpolator is provided with a plurality of slices. Each slice includes a first switch for mixing a first clock signal into an interpolated output signal and a second switch for mixing a second clock signal into the interpolated output signal. In response to a high-resolution signal, at least one of the slices may switch on both the first switch and the second switch.

A circuit includes a RC-CR circuit and a second circuit. The RC-CR circuit outputs a first signal at a first output node over a RC path, and a second signal at a second output node over a CR path. The second circuit is coupled to the RC-CR circuit at the first output node over the RC path. The second circuit includes an array of capacitors coupled in parallel and a plurality of switches, and each of the array of capacitors is connected, in series, to a corresponding switch in the plurality of switches. Each of the array of capacitors and its corresponding switch are coupled between the first output node and a ground. The plurality of switches is switched on or off such that the first signal and the second signal have a phase difference that falls within a predetermined phase range.

A circuit includes a RC-CR circuit and a second circuit. The RC-CR circuit outputs a first signal at a first output node over a RC path, and a second signal at a second output node over a CR path. The second circuit is coupled to the RC-CR circuit at the first output node over the RC path. The second circuit includes an array of capacitors coupled in parallel and a plurality of switches, and each of the array of capacitors is connected, in series, to a corresponding switch in the plurality of switches. Each of the array of capacitors and its corresponding switch are coupled between the first output node and a ground. The plurality of switches is switched on or off such that the first signal and the second signal have a phase difference that falls within a predetermined phase range.

An RF phase offset detection system, which includes a first RF phase detector and a second RF phase detector, and measures a first phase offset between a first RF signal and a second RF signal, is disclosed. Each of the first RF signal and the second RF signal has a common RF frequency. The first RF phase detector detects and filters the first RF signal and the second RF signal to provide a first detection signal. The second RF phase detector receives and phase-shifts the second RF signal to provide a phase-shifted RF signal. The second RF phase detector further detects and filters the first RF signal and the phase-shifted RF signal to provide a second detection signal, such that a combination of the first detection signal and the second detection signal is representative of the first phase offset.