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 pulse generation circuit and stagger pulse generation circuit are provided. The pulse generation circuit includes: an oscillation circuit that receives a control signal and generates a first oscillation signal according to the control signal; a period adjustment circuit that receives the first oscillation signal and a magnification selection signal and outputs a second oscillation signal, the period of the second oscillation signal is a period of the first oscillation signal or a period of an oscillation adjustment signal, and the second oscillation signal is selected according to the magnification selection signal; and a pulse conversion circuit that receives the second oscillation signal and outputs a pulse signal, the pulse of the pulse signal is generated according to the rising or falling edge of the second oscillation signal, and the pulse period of the pulse signal is the same as the oscillation period of the second oscillation signal.

A pulse generation circuit and stagger pulse generation circuit are provided. The pulse generation circuit includes: an oscillation circuit that receives a control signal and generates a first oscillation signal according to the control signal; a period adjustment circuit that receives the first oscillation signal and a magnification selection signal and outputs a second oscillation signal, the period of the second oscillation signal is a period of the first oscillation signal or a period of an oscillation adjustment signal, and the second oscillation signal is selected according to the magnification selection signal; and a pulse conversion circuit that receives the second oscillation signal and outputs a pulse signal, the pulse of the pulse signal is generated according to the rising or falling edge of the second oscillation signal, and the pulse period of the pulse signal is the same as the oscillation period of the second oscillation signal.

A phase interpolator circuit that generates an output clock signal having a phase according to a PI code based on input clock signals, the phase interpolator circuit includes: a first generation circuit configured to generate a first intermediate current based on a first input clock signal according to the PI code; a second generation circuit configured to generate a second intermediate current based on a second input clock signal having a first phase difference from the first input clock signal according to the PI code; a synthesis circuit configured to synthesize the first and second intermediate currents to generate the output clock signal; and a correction circuit configured to correct a current amount of at least one of the intermediate currents based on a correction current according to a correction code set according to at least an amount of shift of the first phase difference from a certain value.

A phase interpolator circuit that generates an output clock signal having a phase according to a PI code based on input clock signals, the phase interpolator circuit includes: a first generation circuit configured to generate a first intermediate current based on a first input clock signal according to the PI code; a second generation circuit configured to generate a second intermediate current based on a second input clock signal having a first phase difference from the first input clock signal according to the PI code; a synthesis circuit configured to synthesize the first and second intermediate currents to generate the output clock signal; and a correction circuit configured to correct a current amount of at least one of the intermediate currents based on a correction current according to a correction code set according to at least an amount of shift of the first phase difference from a certain value.

A phase interpolator circuit has a first stage that selects a pair of phase vectors from among M available sets of pairs and a second stage that interpolates between the selected pair to phase align a sample clock. The interpolation functions applied to selected pairs of phase vectors can differ to account for integral non-linearity, duty-cycle distortion, phase errors, and crosstalk that vary between phase vectors.

A phase interpolator circuit has a first stage that selects a pair of phase vectors from among M available sets of pairs and a second stage that interpolates between the selected pair to phase align a sample clock. The interpolation functions applied to selected pairs of phase vectors can differ to account for integral non-linearity, duty-cycle distortion, phase errors, and crosstalk that vary between phase vectors.

There is provided an optical encoder including a phase shifter circuit, two multiplexers, two digital circuits and four comparators. The phase shifter circuit receives signals from an amplifier and outputs multiple phase shifted signals. Each of the two multiplexers receives a half of the multiple phase shifted signals and outputs two pairs of phase shifted signals, each pair having 180 degrees phase difference, respectively to two comparators connected thereto. Each of the two digital circuits controls the corresponding multiplexer to select the two pairs of phase shifted signals from the half of the multiple phase shifted signals.

There is provided an optical encoder including a phase shifter circuit, two multiplexers, two digital circuits and four comparators. The phase shifter circuit receives signals from an amplifier and outputs multiple phase shifted signals. Each of the two multiplexers receives a half of the multiple phase shifted signals and outputs two pairs of phase shifted signals, each pair having 180 degrees phase difference, respectively to two comparators connected thereto. Each of the two digital circuits controls the corresponding multiplexer to select the two pairs of phase shifted signals from the half of the multiple phase shifted signals.

A delay control circuit includes: a delay cell including a plurality of bias inverters, first RC circuits, and second RC circuits, the delay cell activates a number of first RC circuits in response to a step code, delays a signal by a delay time based on the number of the activated first RC circuits, and outputs the delayed signal; a ZQ calibrator including pull-up and pull-down circuits, the ZQ calibrator adjusts a number of activated pull-up and pull-down circuits, and inputs a pull-up and pull-down voltage, based on a calibration code to the bias inverters; and a step adjuster including a first ring oscillator including test delay cells, the step adjuster determining characteristics of the first and second RC circuits and activates a number of second RC circuits based on the characteristics and an operating frequency of the delay control circuit.