An encoding device includes a processor. The processor configured to determine, based on an integer value that corresponds to a bit string of a predetermined amount, quantities for a predetermined number of individual symbol values included in a symbol sting encoded from the bit string of the predetermined amount. The processor configured to specify positions of symbols in the symbol string for the individual symbol values from the quantities for the individual symbol values and a first parameter related to a number of arrangement patterns of the symbols that corresponds to the quantities for the individual symbol values. The processor configured to generate the symbol string by assigning to the specified positions the corresponding symbol values.

Disclosed is a voltage converter capable of adaptively operating in one of a synchronous mode and an asynchronous mode according to an input voltage of an input terminal. The voltage converter includes: a voltage detector generating a detection result according to the input voltage; a switch control circuit generating a first switch control signal and a second switch control signal according to the detection result and an output voltage of an output terminal; a first switch intermittently turned on according to the first switch control signal in the synchronous and asynchronous modes; a second switch intermittently turned on/off according to the second switch control signal in the synchronous/asynchronous mode; and an energy storage circuit electrically connected to the input and output terminals to store and release energy according to the on-off states of the first and second switches.

Disclosed is a voltage converter capable of adaptively operating in one of a synchronous mode and an asynchronous mode according to an input voltage of an input terminal. The voltage converter includes: a voltage detector generating a detection result according to the input voltage; a switch control circuit generating a first switch control signal and a second switch control signal according to the detection result and an output voltage of an output terminal; a first switch intermittently turned on according to the first switch control signal in the synchronous and asynchronous modes; a second switch intermittently turned on/off according to the second switch control signal in the synchronous/asynchronous mode; and an energy storage circuit electrically connected to the input and output terminals to store and release energy according to the on-off states of the first and second switches.

An embodiment in accordance with the present invention provides a system and method of physically modulating a digital signal across a medium. A signal is sent one bit at a time (serially) as a period of high voltage followed by a period of low voltage. The present invention includes several major advantages. One advantage is that the code to execute the method is very lightweight. Another advantage is that the signals require no synchronization source. The signals of the present invention function as their own synchronization.

An embodiment in accordance with the present invention provides a system and method of physically modulating a digital signal across a medium. A signal is sent one bit at a time (serially) as a period of high voltage followed by a period of low voltage. The present invention includes several major advantages. One advantage is that the code to execute the method is very lightweight. Another advantage is that the signals require no synchronization source. The signals of the present invention function as their own synchronization.

A structure for generating sequences. The structure includes a binary shift register; a feedback structure connected to the shift register arranged to define a linear feedback shift register according to a polynomial; a first output arranged to collect one or more state values from a first group of elements of the shift register, the one or more state values from the first group forming a value of a first sequence; and a second output arranged to collect one or more state values from a second group of elements of the shift register, the one or more state values from the second group forming a value of a second sequence. No element of the second group belongs to the first group.

A PFM control circuit includes a switching circuit, a slope-decision circuit, a flip-flop, a first and a second comparison circuits. The first comparison circuit outputs a first signal according to an output voltage of a power conversion circuit. The switching circuit outputs a switching signal according to an output current of the power conversion circuit. The slope-decision circuit outputs a slope modulation voltage, and determines a slope modulation voltage with a first or a second slope according to the switching signal. The second comparison circuit outputs the second signal according to the slope modulation voltage. The flip-flop outputs a control signal to the power conversion circuit according to the first and the second signals. When the slope modulation voltage has the first or the second slope, the control signal has a first or a second frequency accordingly. The first frequency is higher than the second frequency.

A PFM control circuit includes a switching circuit, a slope-decision circuit, a flip-flop, a first and a second comparison circuits. The first comparison circuit outputs a first signal according to an output voltage of a power conversion circuit. The switching circuit outputs a switching signal according to an output current of the power conversion circuit. The slope-decision circuit outputs a slope modulation voltage, and determines a slope modulation voltage with a first or a second slope according to the switching signal. The second comparison circuit outputs the second signal according to the slope modulation voltage. The flip-flop outputs a control signal to the power conversion circuit according to the first and the second signals. When the slope modulation voltage has the first or the second slope, the control signal has a first or a second frequency accordingly. The first frequency is higher than the second frequency.

A method and apparatus for generating a frequency comb. A sine wave comprising samples is generated at a selected sampling rate and a selected increment corresponding to a number of samples for a period of the sine wave using a lookup table or a CORDIC algorithm. The sine wave is processed by a universal differential equation to generate the frequency comb. Characteristics of the frequency comb generated from the sine wave are controlled by changing the sampling rate and the increment.

A method and apparatus for generating a frequency comb. A sine wave comprising samples is generated at a selected sampling rate and a selected increment corresponding to a number of samples for a period of the sine wave using a lookup table or a CORDIC algorithm. The sine wave is processed by a universal differential equation to generate the frequency comb. Characteristics of the frequency comb generated from the sine wave are controlled by changing the sampling rate and the increment.