122results about "Computations using pulse rate multipliers/dividers" patented technology

A baseband clock synthesizer having particular use in a BLUETOOTH piconet device, having the capability of generating either 12 MHz or 13 MHz clock signals generated from any reference clock signal, e.g., 12.00, 12.80, 13.00, 15.36, 16.80, 19.20, 19.44, 19.68, 19.80, and 26.00 MHz. A fractional-N frequency divider is implemented with a PLL including a variable divider allowing the use of virtually any reference frequency input to generate a locked 156 MHz clock signal used as a basis for a 12 MHz or 13 MHz baseband clock signal. A residue feedback sigma-delta modulator provides a varying integer sequence to an integer divider in a feedback path of the PLL, effectively allowing division by non-integer numbers in the PLL. Thus, the PLL can be referenced to virtually any reference clock and still provide a fixed output clock signal (e.g., 12 or 13 MHz).

A frequency synthesis / multiplication circuit and method for multiplying the frequency of a reference signal. In one embodiment, multiple versions of the reference signal are generated having different phases relative to one another, and these multiple versions are combined to form an output signal having a frequency that is a multiple of the frequency of the reference signal.

A PLL circuit includes a phase comparator; a charge pump; a loop filter; a voltage-controlled oscillator; a frequency dividing circuit; an A counter for dividing the P-frequency-divided output; circuits for generating two signals, which have a phase difference equivalent to one period of the P-frequency-divided output of the frequency dividing circuit; and an interpolator for producing an output signal obtained by interpolating the phase difference between the two signals in accordance with an interior division ratio. The interpolator interpolates in steps of a value obtained by dividing the phase difference by P and incrementing or decrementing a value B, which decides an interior division ratio B:P−B, by B whenever frequency-division by A is performed, and a control circuit. The phase of the output of the interpolator is fed to the phase comparator and compared with the phase of a reference clock, and divides by a frequency-dividing factor.

A novel clock control circuit and method in which phase synchronization with respect to an external clock can be realized without recourse to the external clocks. A clock controlling circuit includes a delay circuit sequence comprised of N stages of units each made up of a first delay circuit 10 and a first interior division circuit 11 for delaying the output signal of the first delay circuit, and a phase difference detection circuit 14 for detecting the clock period and the delay time difference of the delay circuit sequence from the input clock IN and a clock END output by the delay circuit sequence as a phase difference of the two signals. A plural number of second interior division circuits 12, fed with an output signal of the first delay circuit, delays a transition edge of an output signal of the first delay circuit by t2-nxT / N to output the delayed signal. The second interior division circuit outputs a signal which makes transition at a timing delayed nxtCK / N as from the start time point of the clock cycle. A synthesis circuit 13 generates a frequency multiplied clock signal which is obtained on equal division of the clock period tCK of the input clock from the input clock IN and the number 1 to number N-1 third delays circuit.

The present invention provides a method and apparatus for synchronizing signal transfers between two clock domains, where the clock domains have a gear ratio relationship. A gear ratio means that the clocks are related by a ratio, such that each clock has a different integer number of clock cycles in a common period. Also, in addition to a gear ratio relationship, the clocks may have a synchronized edge at the end of the common period. For each clock, the cycles in the common period are “colored”, i.e., identified by a number (1st, 2nd, etc.). By using the coloring technique, the appropriate clock edge to perform a data or control signal transfer can be identified. The edges are preferably chosen to minimize the latency of the transfer.

A frequency synthesizer is provided in the present invention. The frequency synthesizer includes a single phase-locked loop having a reference frequency signal input, a first output, a second output and a pair of divide-by-N circuits coupled with each other and electrically connected to the second output; a multiply-by-M circuit having a first input electrically connected to the first output and a third output; and a combination of a buffer and a mixer having a second input electrically connected to the second output and a third input electrically connected to the third output generating a frequency signal output.

Timing difference division circuit with a high operating speed and a small area, assuring broadband operation. The circuit includes a logic circuit L1 generating a first gate signal and a second gate signal based on a first input signal and a second input signal, a first switch element connected across a first power source and an inner node and having a control terminal to which is fed the first gate signal, a first series circuit made up of a second switch element and a first constant current source and a second series circuit made up of a third switch element and a second constant current source. The first and second series circuits are connected in parallel across the inner node and the second power source. The first and second gate signals are connected to control terminals of the second and third switches, respectively. The circuit also includes a plurality of MOS capacitors, connection of which to the inner node is separately controlled by a control signal, and a buffer circuit an input end of which is connected to the inner node and the value of an output signal of which is determined based on the relative magnitude of the potential of the inner node and a threshold voltage. An overlap period during which the first and second gate signals output from the logic circuit are both activated to turn on the second and third switch elements is set to an optional value.

The semiconductor device is provided with a clock signal generation circuit that includes a reference clock signal generation circuit which generates a first reference clock signal, a first counter circuit which counts the number of rising edges of the first reference clock signal by using the first reference clock signal and a synchronizing signal, a second counter circuit which counts the number of rising edges of the first reference clock signal by using an enumerated value of the first counter circuit, a first divider circuit which divides a frequency of the first reference clock signal by using the enumerated value of the first counter circuit and generates a second reference clock signal, and a second divider circuit which divides a frequency of the second reference clock signal and generates a clock signal.

A serializer receives parallel data and a control signal. The serializer splits the parallel data into multiple subportions of data and, based on the control signal, sequentially outputs each of said subportions as serial output data in one or more serial output channels. The number of serial output channels is dictated by the control signal.

A DLL of a memory device having a normal mode and a power down mode includes a clock buffer for buffering an external clock signal to output an internal clock signal. A power down mode controller generates a power down mode control signal to define the normal mode or the power down mode in response to a clock enable signal. A source clock generation unit receives the internal clock signal to generate a DLL source clock signal under the control of the power down mode control signal. A phase update unit performs a phase update operation based on the DLL source clock signal to output a DLL clock signal.