Embodiments included herein are directed towards a fractional feedback divider circuit and associated method. The circuit may include a programmable feedback divider including a plurality of flip-flops arranged in series. The programmable feedback divider may be configured to receive an input clock signal and a reset signal comprising at least one pulse and to generate a divided clock. The circuit may include reset logic configured to receive an input from the programmable feedback divider and to generate a reset signal. The circuit may include a first D flip-flop configured to receive the reset signal and to generate an output and a second D flip-flop configured to receive the output from the first D flip-flop and to generate a second output. The circuit may further include a multiplexer configured to receive the second output and to generate an output clock signal.

Embodiments included herein are directed towards a fractional feedback divider circuit and associated method. The circuit may include a programmable feedback divider including a plurality of flip-flops arranged in series. The programmable feedback divider may be configured to receive an input clock signal and a reset signal comprising at least one pulse and to generate a divided clock. The circuit may include reset logic configured to receive an input from the programmable feedback divider and to generate a reset signal. The circuit may include a first D flip-flop configured to receive the reset signal and to generate an output and a second D flip-flop configured to receive the output from the first D flip-flop and to generate a second output. The circuit may further include a multiplexer configured to receive the second output and to generate an output clock signal.

A clock divider includes, in part, a pair of counters and a programmable delay line. A first one of the counters operates at a first frequency and is configured to count using a first integer portion of the divisor. The second counter operates at a second frequency smaller than the first frequency and is configured to count using a second integer portion of the divisor. The programmable delay line includes, in part, a chain of delay elements configured to generate a multitude of delays of the output of the second counter. A multiplexer selects one of the generated delays in accordance with the fractional portion of the divisor. The second counter increases its count only when the first counter reaches a terminal count. The first and second integer portions are loaded respectively into the first and second counters when the second counter reaches its terminal count.

A programmable frequency divider includes a modulus frequency divider, a pulse counter, and a swallow counter. The pulse counter is configured to count an output signal from the modulus frequency divider, and output a frequency division signal, and the swallow counter is configured to count the output signal from the modulus frequency divider and perform resetting on the basis of the frequency division signal from the pulse counter, the programmable frequency divider being configured to control the modulus frequency divider on the basis of a signal from the swallow counter. The programmable frequency divider includes a control signal delay circuit, disposed between an output terminal of the swallow counter and a control terminal of the modulus frequency divider, configured to delay a signal from the swallow counter, and generate a control signal for controlling the modulus frequency divider.

A signal distribution system includes: a first signal divider arranged to generate a first output oscillating signal according to a first input oscillating signal; a second signal divider arranged to generate a second output oscillating signal according to the first input oscillating signal; a first transmitting channel coupled to the first signal divider and the second divider for transmitting the first input oscillating signal to the first signal divider and the second signal divider; and a second transmitting channel coupled to the first signal divider and the second divider for transmitting a second input oscillating signal to the first signal divider and the second signal divider; wherein the first input oscillating signal has a first frequency, the second input oscillating signal has a second frequency, and the second frequency is smaller than the first frequency.

A signal distribution system includes: a first signal divider arranged to generate a first output oscillating signal according to a first input oscillating signal; a second signal divider arranged to generate a second output oscillating signal according to the first input oscillating signal; a first transmitting channel coupled to the first signal divider and the second divider for transmitting the first input oscillating signal to the first signal divider and the second signal divider; and a second transmitting channel coupled to the first signal divider and the second divider for transmitting a second input oscillating signal to the first signal divider and the second signal divider; wherein the first input oscillating signal has a first frequency, the second input oscillating signal has a second frequency, and the second frequency is smaller than the first frequency.

A frequency divider circuit includes: a first frequency dividing circuit configured to divide a first clock signal to generate a first frequency-divided clock signal; a second frequency dividing circuit configured to divide a second clock signal having the same frequency as the first clock signal and having a first phase difference with respect to the first clock signal to generate a second frequency-divided clock signal; a detection circuit configured to detect a phase relationship between the first frequency-divided clock signal and the second frequency-divided clock signal; and a selection circuit configured to select and output one of the second frequency-divided clock signal and an inverted signal of the second frequency-divided clock signal which are generated by the second frequency dividing circuit, based on the phase relationship between the first frequency-divided clock signal and the second frequency-divided clock signal detected by the detection circuit.

A signal divider includes: a dividing circuit arranged to generate an output oscillating signal according to a first input oscillating signal; and a signal generating circuit, coupled to the dividing circuit, for generating an injection signal to the dividing circuit. The dividing circuit is arranged to generate the output oscillating signal with a predetermined phase according to the injection signal and the first input oscillating signal.

A divider and buffer circuit uses a receive command to initiate a reset of buffer circuitry prior to restarting to avoid a metastable state. For example, the divider and buffer circuit includes a first buffer circuit, a second buffer circuit, and a reset circuit. The reset circuit receives a command and provide a pulse on a reset signal in response to the command. In response to the reset pulse, the first buffer circuit provides a first divided clock signal having a first logical value based on respective logical values of received complementary clock signals and the second buffer circuit provides a second divided clock signal having a second logical value based on the respective logical values of the complementary clock signals. The command is a CAS SYNC command, in some examples.

The present disclosure provides a low-jitter frequency division clock circuit, including: a clock control signal generation circuit, to generate clock signals having different phases; a low-level narrow pulse width clock control signal generation circuit, to generate a low-level narrow pulse width clock control signal; a high-level narrow pulse width clock control signal generation circuit, to generate a high-level narrow pulse width clock control signal; and a frequency division clock generation circuit, to generate a frequency division clock signal according to low-level narrow pulse width clock control signal and high-level narrow pulse width clock control signal. The delay from a clock input end to an output end of low-jitter frequency division clock circuit is up to three logic gates. Compared with traditional divide-by-2 frequency division clock circuits based on D-flip-flop, the low-jitter frequency division clock circuit of the present disclosure has fewer logic gates, a shorter delay, and lower jitter.