Abstract: A clock multiplier includes a phase-locked loop (PLL), a bias generator, a counter, a selection circuit, a flip-flop, a phase comparator, a delay controller and a variable delay circuit. The variable delay circuit, which is biased by a delay cell bias signal, delays a reference signal by a first delay time and by a second time that is longer than the first delay time, and generates a first feedback signal corresponding to the first delay time, and a second feedback signal corresponding to the second delay time. Therefore, a clock multiplier may reduce the size of a delay cell and may be designed to be insensitive to changes in environmental conditions, such as a process, a voltage, a temperature, and so on.

Abstract: A phase lockedcircuit comprising a phase detector for comparing an incoming serial data signal with a feedback clock signal and generating a digital phase detector output signal representing a phase difference between the incoming data signal and the feedback clock signal; a dual path filter for receiving the phase detector output signal, the dual path filter including a first path for generating a digital proportional output signal that is proportional to the phase detector output signal and a second path having an integral digital filter for generating a digital integral output signal that is proportional to an integral of the phase detector output signal; and a digitally controlled oscillator for receiving the proportional output signal and the integral output signal as tuning inputs and generating in dependence thereon an output clock signal from which the feedback clock signal is obtained. The circuit can be implemented in a receive path of a serializer/deserializer.

Abstract: Digital delay-locked loops (DLLs) and methods are provided for signal frequency multiplication. Analog delay elements of typical frequency-multiplying DLLs are replaced with digital and digitally-controlled elements including a variable delay line. The number of unit delay elements in the delay line can be selected to produce a desired output signal delay. Phase-mixing of multiple variable delay line outputs achieves finer delay-time adjustments.

Abstract: The present invention relates to a method for synchronizing a number of digital clocks to a synchronizing signal, said method comprising generating centrally a reference clock, synthesizing said digital clocks from said reference clock using a clock multiplier, respectively, resetting said clock multiplier in response to said synchronizing signal, and masking an output signal of said clock multiplier during settling time of said clock multiplier.

Abstract: The present invention relates to a circuit providing frequency-doubling function. More particularly, the present invention relates to a frequency doubler circuit comprising dual Gilbert mixers in replace with the single mixer scheme in the conventional direct conversion transceiver circuit. CMOS technology is preferred in order to lower size and power consumption of the specific IC. With a balanced output load, either is resistor-capacitor (RC) load, resistor-inductor (RL) load, or a combination of the three (RLC), symmetrical output waveforms are obtained thereby. Notice that two quadrature inputs and their inverse-phase signals are provided to the purposed dual Gilbert mixer circuit, and two outputs in inverse-phase are obtained accordingly as meditated in this invention.

Abstract: An integrated circuit may include a receiver and/or a transmitter that performs third order sub-harmonic conversion. The integrated circuit may include a Gilbert cell active mixer with three or more serially-connected transistors in each of the mixer's four branches. Alternatively, the integrated circuit may include a quad-ring passive resistive mixer with three or more serially-connected transistors in each of the mixer's four branches. Alternatively, the integrated circuit may include a logic circuit and a mixer. The logic circuit may apply logic operations to periodic logic signals having a local frequency and to delayed versions thereof to produce reference signals having a dominant spectral component at three times the local frequency. The mixer may mix input signals with the reference signals to produce output signals having a dominant spectral component at three times the local frequency less a center frequency of the input signals.

Abstract: A clock multiplier for multiplying an input clock by N includes a phase/frequency detector, a clock selector, and a voltage-controlled delay line. The phase/frequency detector generates a first control signal and a second control signal according to a frequency/phase difference between the input clock and a count signal indicating a signal that is generated by delaying the input clock N times. The clock selector selects one of the input clock and a feedback clock based on the input clock and the count signal. The voltage-controlled delay line adjusts a delay time of the selected signal according to a control voltage that is generated based on the first control signal and the second control signal, and outputs the feedback clock based on the adjusted signal. The clock multiplier operates without accumulating a frequency/phase difference between the input clock and the output clock when the multiplying ratio is increased.

Abstract: When a signal of a double frequency is generated from the original signal, conventionally a 90-degree phase-shift circuit is necessary to suppress an output of a DC component and efficiently obtain a double wave. According to the present invention, an equal RF signal is inputted to input terminals and an output is matched with a frequency as high as that of the original frequency in a Gillbert cell double-balanced mixer, so that a doubled output is obtained with no DC offset. According to the circuit configuration of the present invention, it is possible to provide a circuit readily performing integration and to efficiently output only a double frequency merely by inputting a simple differential signal without the need for the original signal which has been phase controlled. Further, a DC short circuit in the resonance circuit makes it possible to eliminate a DC offset voltage in an output.

Abstract: A mixer circuit (50) includes a first switching mixer (20A) with a first desired signal input (RF+ and RF?), a first switching signal input (LO+& LO?), and a first output (IF+ and IF?), a second switching mixer (20B), and a third switching mixer (20C) with corresponding desired signal inputs, switching signal inputs, and outputs. An overall input signal to the mixer circuit is fed to an input port (56) of the first switching mixer, an output from an output port (57) of the first switching mixer is fed to an input port (58) of the second switching mixer, the output from an output port (59) of the second switching mixer is fed to an input port (60) of the third switching mixer, and an overall output of the mixer circuit can be an output from an output port (62) of the third switching mixer.

Abstract: A circuit and corresponding method for doubling the frequency of an input signal, even when the input signal is of low frequency or a square wave. The input signal is applied to a phase-shifting circuit that produces a pair of output signals that are theoretically 90° apart in phase, but may lack the desired form if the original input signal is of low frequency. The waveforms of the two output signals are enhanced in latching hysteresis buffers that produce more uniformly squared waves, with zero crossings corrected to be more exactly 90° apart and with desirably steep state transitions. The enhanced-waveform output signals are coupled to an exclusive OR (XOR) gate to produce a double-frequency output.

Abstract: Clock multiplier circuits and methods use counters to define the positions of the output clock edges. A plurality of counters are each clocked by a count clock relatively much faster than the input clock. A first counter counts for one input clock period, and the counted value is stored. The stored value is then divided and the divided values are combined to provide counter stop values representing the numbers of counts in various fractions of the input clock period. A second counter counts from an initial value starting from a first edge of the input clock, and the count is compared in turn to the each of the counter stop values. When the value in the second counter matches one of the counter stop values, a pulse is generated on the output clock signal. Thus, the second counter generates a series of pulses at predetermined times in the input clock period.

Abstract: A multiplier core outputs a single-phase signal containing a frequency component having a frequency which is an even multiple of the frequency of an input signal. A differential amplifier includes first and second nMOS transistors having respective source terminals connected to each other. The output signal from the multiplier core is inputted to the gate terminal of the first nMOS transistor, and the gate terminal of the second nMOS transistor is AC grounded. The differential amplifier differentially amplifies the signals inputted to the gate terminals of the first and second nMOS transistors to output a potential at the drain terminals of the first and second nMOS transistors as a differential signal. The output terminal of the multiplier core is connected through a series LC circuit to the source terminals of the first and second nMOS transistors.

Abstract: An integrated circuit, where a hard macro is resident within the integrated circuit. The hard macro receives a clock signal at a frequency that is below the operational frequency of the integrated circuit, and produces a clock signal having a frequency that is at least equal to the operational frequency of the integrated circuit. The hard macro has a first input that receives a first signal from the tester. A second input receives a second signal from the tester, offset by substantially ninety degrees from the phase of the first signal. A speed select input receives a signal, where the signal is selectively set at one of a logical high indicating a first multiplier to be applied in the hard macro, and a logical low indicating a second multiplier to be applied in the hard macro. A clock multiplication circuit receives the first signal, selectively receives the second signal, and receives the speed select signal, and produces the clock signal.

Abstract: A double frequency signal generator to which a synchronization signal having a duty cycle of 1% to 999% is inputted. The synchronization signal is used for triggering of a switching component at positive and negative edges to generate a triangular-wave signal. An average of voltages of the triangular-wave signal is acquired and compared with the triangular-wave signal at a comparator to generate a square-wave having a duty cycle of 50%. Then, the square-wave signal is used for triggering at positive and negative edges to generate a double frequency signal. As such, the high cost issue and the limitation of a square-wave input signal occurred in the prior art may be efficiently overcome.

Abstract: A clock frequency multiplier is provided. The clock frequency multiplier comprises a tracking circuit, a pulsing circuit, and a shaping circuit. The tracking circuit receives a clearing signal and a reference clock signal, outputs the quotient of the number of cycles of the reference clock signal in a cycle of the clearing signal divided by a first predetermined value. The pulsing circuit outputs a pulsing signal wherein the frequency of the pulsing signal is the frequency of the clearing signal multiplied by the first predetermined value. The shaping circuit divides the frequency of the pulsing signal by a second predetermined value and shapes the pulsing signal into a clock signal with a predetermined duty cycle, and outputs the divided and shaped pulsing signal as an output clock signal.

Abstract: Provided is a frequency multiplier including a delay circuit, an XOR gate, and a control circuit and a method of operating such a frequency multiplier to adjust the duty cycle of a clock signal. During operation of the frequency multiplier the delay circuit receives a first clock signal and generates a delayed clock signal. The XOR gate receives the first clock signal and the delayed clock signal, performs an XOR operation on the received signals and outputs a second clock signal that has a frequency that is a multiple of the first clock signal. The control circuit monitors the phase difference between the first clock signal and the delayed clock signal and outputs a control signal corresponding to the detected phase difference to the delay circuit to adjust the time delay applied to the first clock signal by the delay circuit.

Abstract: In a duty adjustment circuit, a clock signal is frequency-divided to ½n by a frequency divider. In a first frequency doubler among n cascade-connected frequency doublers, the divided clock signal is delayed by a variable delay portion according to a control signal. The exclusive logical sum of the delayed signal and the divided clock signal in the frequency-doubling portion doubles the frequency. The average voltage of the frequency-doubled signal is detected by an average value detection portion, and is compared with a reference voltage by a comparison control portion. A control signal is fed back to the variable delay portion to cause the average voltage to become equal to the reference voltage. In this manner, a clock signal is generated from the last frequency doubler with frequency equal to that of the original clock signal, and with duty ratio adjusted to a desired value.

Abstract: Digital phase mixers with enhanced speed are provided. A phase mixer generates a signal having a phase between the phases of two input signals based on select signals. The propagation delay of the output signal is reduced by using a first voltage source to drive the input signals and the output signal and a second voltage source, having a higher voltage than the first voltage source, to drive the select signals. The higher voltage source reduces the impedance of each transistor driven by the select signals, thus reducing the propagation delay at the output of the phase mixer. For a non-differential digital phase mixer, the propagation delay is reduced in the rising edges of the output signal. For a differential digital phase mixer, the propagation delay is reduced in the rising and falling edges of the output signal.

Abstract: A direct conversion circuit that not only down-converts the received modulated signal using a down-converting mixer into a baseband signal, but also, after performing a passive low pass filtering to remove higher-order components, performs up-conversion of the baseband signal using an up-converting mixer. Active elements such as highly sensitive amplifiers do not operate on the baseband signal itself, but on the up-converted version of that baseband signal, thereby reducing the 1/f noise introduced by those active elements. The downstream circuitry after the up-conversion may be coupled by intervening capacitors since the downstream circuitry is operating on a higher frequency signal. Accordingly, the DC offset introduced by the downstream active elements is reduced.

Abstract: An invention is provided for generating custom clock frequencies within a processor core. A CPU clock signal propagates through a DLL circuit. Further, a control signal controls the CPU clock signal as the signals propagate through multiple inverters in the DLL circuit. The multiple inverters delay the CPU clock signal and generate multiple output signals. Subsequently, the multiple output signals are combined to generate a higher frequency signal than the CPU clock signal. To control the CPU clock signal, the DLL circuit includes a charge pump to lock in a precise control signal. The charge pump further includes circuitry, such as a Schmitt circuit, to increase and decrease voltage.

Abstract: A digital clock frequency doubler for increasing an input frequency of an input clock signal includes an input block, and a generator block. The input block receives the input clock signal, and generates a pulse signal having an ON period equal to the input clock signal period. The generator block is coupled to the input block. The generator block receives the pulse signal and divides a period of the pulse signal by a period of a high frequency digital signal and then generates an output clock signal with an output frequency that is about two times the input frequency.

Abstract: A method for adjusting a programmable mixer of a local oscillation module to reduce local oscillation leakage begins by determining at least one of: DC offset of an input signal of the programmable mixer and process mismatches between a first mixing stage and a second mixing stage. The method continues by determining operational characteristics mismatch between the first mixing stage and the second mixing stage based on the at least one of the DC offset and process mismatches. The method continues by generating a control signal to substantially compensate for the operational characteristics mismatch. The method continues by providing the control signal to a compensation module, wherein the compensation module modifies operational characteristics of at least one of the first and second mixing stages based on the control signal such that the operational characteristics of the first mixing stage substantially equals the operational characteristics of the second mixing stage.

Abstract: A means for obtaining an output signal which is the sum of the frequencies of two periodic input signals that may vary in amplitude and frequency over time. The apparatus, which provides means for realizing trigonometric functions of the form sin(?+?)=2 sin ? cos ??sin(???) or sin n?=2 sin(n?1)? cos ??sin(n?2)?, comprises three basic circuit elements including one or more analog multipliers, one or more envelope detectors, and a subtracter. A method is disclosed for generating a series of even and odd harmonics of a single continuously varying input signal using a plurality of cascaded harmonic generator circuits.

Abstract: A phase locked loop (PLL) is provided. In one implementation, the PLL includes a feedback loop having a frequency multiplier and an integer divider to generate a divided signal. The PLL includes a re-sampling circuit operable to re-sample one or more digital pulses of the divided signal using one or more phase signals if a multiplication factor of the frequency multiplier does not divide evenly into the integer divisor.

Abstract: A zero intermediate frequency (ZIF) radio frequency (RF) digital mixer (200) includes a low noise amplifier (LNA) (203), a first RF mixer stage (205) for mixing an RF signal from the at least one LNA with a first local oscillator signal operating a first predetermined frequency. A second RF mixer stage (207) is then utilized for mixing in-phase (I) and quadrature (Q) digital signals from the first RF mixer stage (205) with a plurality of second local oscillator signals (LO) operating at a second predetermined frequency. The invention significantly improves current drain by eliminating the need for a linear transconductance stage while still maintaining high degrees of isolation and linearity.

Abstract: A receiver apparatus is provided with a receiver section including an amplifying stage for amplifying a high frequency signal received by an antenna, a frequency converting stage for converting a frequency of the output signal of the amplifying stage, a local oscillator for supplying a local oscillating signal to the frequency converting stage, and a signal processing section for supplying a control signal to the receiver section depending on signal intensity inputted to the receiver section, or to the signal processing section from the receiver section. The frequency converting section includes a plurality of parallel frequency converters, and an adder for adding output signals of the frequency converters. The signal processing section controls the number of the frequency converters to be operated.

Abstract: A method and circuit for synchronizing an input clock signal with a plurality of internal clock signals in a multiple phase Pulse Width Modulation (PWM) switching power supply without using a Phase Locked Loop (PLL). A period of the input clock signal is measured by using a frequency to voltage converter. A reference capacitor charged by a constant current source is arranged to generate a reference voltage with a slope based on the period of the input clock signal. A change in the reference voltage across the reference capacitor is substantially inversely proportional to a frequency of the input clock. By providing the reference voltage to a sample-and-hold circuit and using an output of the sample-and-hold circuit to feed a comparator, synchronization may be accomplished. Each internal clock signal is generated by different reference capacitor and current source circuit.

Abstract: A method and system utilize a processor's digital timer and two interrupts to form a frequency multiplier. The first interrupt's processing time window is definable by a first number of counts C1 of the digital timer while the second interrupt's processing time window is definable by a second number of counts C2 of the digital timer. A count value CV utilized by the system/method is based on a desired frequency multiplier N, the timer clock rate, and the time required for one cycle of an input signal. The first interrupt is triggered upon completion of one cycle of the input signal at which point the processing time window associated therewith begins. The second interrupt is triggered each time the timer's overflow signal is generated at which point the processing time window associated with the second interrupt begins.

Abstract: A clock doubler including clock doubling circuitry for generating from a system clock a clock signal having a frequency substantially double that of the system clock and also having a pulse width and associated duty cycle is provided. Timing circuitry for generating a first signal indicative of the time the clock signal is low and a second signal indicative of the time the clock signal is high provides an input to comparison circuitry for comparing the first signal and the second signal. Pulse width varying circuitry varies the pulse width of the clock signal based on the result of comparing the first signal and the second signal.

Abstract: An image rejection mixer (IRM) for rejecting signals having image frequency and, more particularly, a mixer for rejecting signals of image frequency by using mismatch compensation is provided. The image rejection mixer comprises: first and second mixers; first and second converting means, each of which transforms each output of the first and second mixers to digital signal; third and fourth mixers, each of which mixes output of the first converting means with each of second local oscillation in-phase signal and quadrature-phase signal, respectively; fifth and sixth mixers, each of which mixes output of the second converting means with each of second local oscillation in-phase signal and quadrature-phase signal, respectively; means for subtracting; means for adding; and means for compensating gain-mismatch between the first and second mixers.

Abstract: A circuit consistent with certain embodiments of the present invention has a source of N reference clock frequencies (230), where N is an integer greater than one. N frequency extender circuits (954) receive the N reference clock frequencies and generating N frequency extended output clock signals therefrom. A plurality of N seed slewers (958) produce N seed update values. A plurality of N seed registers (962) each receive one of the N seed update values and produce N seed masks therefrom. A plurality of N logic circuits (966) each receive one of the N seed masks and one of the N frequency extended output clock signals. Each of the N logic circuits (966) produce a pseudorandom sequence from the seed mask and the frequency extended output clock signal. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: Methods and systems for fully differential frequency doubling include receiving a differential input signal having a first frequency, generating a non-inverted or positive output signal having twice the frequency of the input signal, and generating an inverted or negative version of the positive output signal. The positive and negative output signals form a fully differential output. The duty ratio of the output signals substantially matches a duty ratio of the input signals. Fully differential frequency doubling can be implemented with NMOS and/or PMOS devices. The invention further provides optional circuitry for increasing an output signal level.

Abstract: Clock doubler circuits and methods use counters to define the positions of the output clock edges. A plurality of counters are each clocked by a count clock relatively much faster than the input clock. A first counter counts for one input clock period, and the counted value is stored. The stored value is divided by two to provide the number of counts in half of the input clock period. The divided value is provided to a second counter that counts from zero to the divided value. Thus, the second counter generates a pulse halfway through the input clock period. Other counters running at the same clock rate can be used to generate pulses at other times in the input clock cycle, as desired. The pulses from the counters are used in combination with the input clock signal to provide output clock edges at predetermined times during the input clock cycle.

Abstract: A passive harmonic switch mixer is shown that is immune to self mixing of the local oscillator greatly reducing leakage noise, pulling noise, and flicker noise when used in a direct conversion receiver or direct conversion transmitter circuit. The passive harmonic switch mixermixes an input signal received on an input port with an in-phase oscillator signal and a quadrature-phase oscillator signal and outputs an output signal on an output port. Because the quadrature-phase oscillator signal is the in-phase oscillator signal phase shifted by 90 °, the passive harmonic switch mixer operates with a local oscillator running at half the frequency of the carrier frequency of an RF signal. Additionally, because the passive harmonic switch mixer has no active components, the DC current passing through each switch device is reduced and the associated flicker noise of the mixer is also greatly reduced.

Abstract: The invention can be used for telecommunications, measuring and other devices in order to produce stable superhigh frequency signals. An IMPATT diode (4) operating in the cascade break-down mode and having a sharp nonlinearity transforms an input signal in such a way that ultraharmonics which multiple in respect to the frequency of an input signal ?0 occur in a frequency spectrum. An output stage of a multiplier is used in order to separate an output n?0 frequency and to suppress adjacent frequencies. In order to tune the output stage to the n?0 frequency, a tuning plug (8) and short-circuiting pistons (13) are used. The tuning plug (8) is arranged above an upper electrod of the IMPATT diode (4) (inside the axis of the diode). The tuning plugs (13) make it possible to tune resonance capacitance to the n?0 frequency and remove energy towards the output part of a T-bend in which a wave guide pass-band filter (15) is disposed.

Abstract: Digital delay-locked loops (DLLs) and methods are provided for signal frequency multiplication. Analog delay elements of typical frequency-multiplying DLLs are replaced with digital and digitally-controlled elements including a variable delay line. The number of unit delay elements in the delay line can be selected to produce a desired output signal delay. Phase-mixing of multiple variable delay line outputs achieves finer delay-time adjustments.

Abstract: In a frequency multiplier and a method of multiplying a frequency of an external clock signal, a data output buffer, and a semiconductor device including the frequency multiplier and the data output buffer, the frequency multiplier receives an external clock signal having a predetermined frequency and outputs an internal clock signal having greater frequency than the predetermined frequency. In the semiconductor device, the data output buffer outputs data tested in response to test data. Therefore, it is possible to test a plurality of memory cells at a time by using a clock signal having a low frequency. In addition, the time and cost required for the test can be greatly reduced, and conventional testing equipment that operates at a relatively low frequency can be effectively used.

Abstract: A clock multiplier capable of modulating the duty cycle of the output clock comprises a first clock multiplication circuit, an inverter, a first low pass filter, a second low pass filter and an amplifier, the first multiplication clock being operative to multiply the frequency of an input clock, the inverter being operative to invert the input clock, the first low pass filter receiving the output clock of the inverter for being charged or discharged, the second low pass filter receiving the output clock of the first clock multiplication circuit for being charged or discharged, the amplifier being operative to compare the output voltages of the first low pass filter and the second low pass filter to perform a feedback control, so as to modulate the duty cycle of the output clock of the first multiplication clock to approach 50%.

Abstract: The frequency doubling circuit and method provides an output signal with stable frequency and a 50% duty cycle. The frequency of the output signal is two times a frequency of the input signal. The circuit only requires four comparators, eight small capacitors, and some switches and transistors for frequency doubling applications. With the help of feedforward structure, the circuit has an almost-instantaneous response. The performance of the provided frequency doubling circuit and method is independent of the frequency and duty cycle of input signal, power supply voltage, temperature, and process variations.

Abstract: A method and arrangement for receiving a frequency modulated signal, includes mixing the frequency modulated signal into a low-frequency signal, detecting the falling and rising edges of said low-frequency signal and forming a second signal on the basis of the edge detection, where the frequency of the second signal is twice the frequency of the low-frequency signal, and frequency detecting the second signal to form a demodulated signal.

Abstract: Digital phase mixers with enhanced speed are provided. A phase mixer generates a signal having a phase between the phases of two input signals based on select signals. The propagation delay of the output signal is reduced by using a first voltage source to drive the input signals and the output signal and a second voltage source, having a higher voltage than the first voltage source, to drive the select signals. The higher voltage source reduces the impedance of each transistor driven by the select signals, thus reducing the propagation delay at the output of the phase mixer. For a non-differential digital phase mixer, the propagation delay is reduced in the rising edges of the output signal. For a differential digital phase mixer, the propagation delay is reduced in the rising and falling edges of the output signal.

Abstract: A phase comparison of timing signals is made by combinational circuitry which receives the timing signals and a window signal, the window signal identifying edges of the timing signals to be compared. The comparison may result in a charge pumped output which can be fed back to control the phase of one of the timing signals. The phase comparator and charge pump circuit can be included in a multiplier circuitry in which the phase of an input signal is directly compared to the phase of an edge of the multiplied signal.

Abstract: A multiplication circuit and a phase synchronization circuit as components of a digital PLL circuit adjust an oscillation frequency and a phase, respectively, of a multiplied clock by adjusting a count value of a digital counter. A CPU sets a count value for oscillating an oscillation circuit of the multiplication circuit at a frequency which is the same as that of a reference clock or is a multiple of the frequency of the reference clock in a digital counter of the multiplication circuit in accordance with a program set by the user of the information processing apparatus, and sets a count value for synchronizing the phase of an output clock with the phase of the reference clock in a digital counter of the phase synchronization circuit.

Abstract: Clock doubler circuits and methods use counters to define the positions of the output clock edges. A plurality of counters are each clocked by a count clock relatively much faster than the input clock. A first counter counts for one input clock period, and the counted value is stored. The stored value is divided by two to provide the number of counts in half of the input clock period. The divided value is provided to a second counter that counts from zero to the divided value. Thus, the second counter generates a pulse halfway through the input clock period. Other counters running at the same clock rate can be used to generate pulses at other times in the input clock cycle, as desired. The pulses from the counters are used to provide output clock edges at predetermined times during the input clock cycle.

Abstract: A clock multiplier circuit receives a clock input signal and generates a clock output signal. The clock multiplier circuit generates a number of pulses to be used as the clock output signal, wherein the pulses have a pulsewidth that is independent of the number of pulses generated and independent of the frequency of the clock input signal. The clock multiplier circuit includes an oscillator and a logic circuit which generates a control signal for synchronization of the pulses to the control signal and to mask the pulses after a selected number of pulses have been output as the clock output signal. The clock multiplier circuit causes a number of unmasked pulses to be output as the clock output signal in response to the control signal, while other pulses are masked.

Abstract: A method for generating a signal with a frequency equal to a product of a reference frequency and a real number includes providing an output signal from an oscillator, and performing a first integer division of a frequency of the output signal by a first integer divider to obtain a first intermediate signal. A first measurement signal representative of a time difference between the first intermediate signal and a reference signal having the reference frequency is determined. The method further includes generating a first comparison signal derived from the first measurement signal, and generating a second comparison signal dependent on a period of the reference signal, on integer and decimal parts of the real number and on the first integer divider. The first and second comparison signals are compared to obtain an error signal representative of a time difference between a period of a current output signal and the period of the reference signal.

Abstract: One embodiment of the invention is directed to a method comprising an act of generating a timing signal, wherein at least some rising edges of the timing signal are based on edges of a first delay signal having a first period and a first phase, and at least some falling edges of the timing signal are based on edges of a second delay signal having a second period that is substantially the same as the first period, and a second phase that is different from the first phase. Another embodiment of the invention is directed to a programmable clock synthesizer comprising an edge-triggered circuit that receives a rising edge delay signal and a falling edge delay signal, wherein the edge-triggered circuit is adapted to generate a synthesized clock signal having rising edges triggered in response to edges of the rising edge delay signal and falling edges triggered in response to edges of the falling edge delay signal.

Abstract: Clock multiplier circuits and methods use counters to define the positions of the output clock edges. A plurality of counters are each clocked by a count clock relatively much faster than the input clock. A first counter counts for one input clock period, and the counted value is stored. The stored value is then divided and added to provide the number of counts in various fractions of the input clock period. The divided and/or added values are provided to a second counter that counts from zero and generates various pulses at desired times throughout the input clock period. The pulses from the second counter are used (sometimes in combination with the input clock signal) to provide output clock edges at predetermined times during the input clock cycle.

Abstract: Phased clock generator circuits and methods that use counters to define the desired positions of the phased output clock edges. A plurality of counters are each clocked by a count clock relatively much faster than the input clock. A first counter counts for one input clock period, and the counted value is stored. The stored value is then divided and added to provide the number of counts in various fractions of the input clock period. The divided and/or added values are provided to a second counter that counts from zero and generates various pulses at desired times throughout the input clock period. The pulses from the second counter are used (sometimes in combination with the input clock signal) to provide phased output clock signals at predetermined times during the input clock cycle. Some embodiments include a duty cycle correction feature. In some embodiments, duty cycle correction is optional.

Abstract: Various circuit techniques for implementing ultra high speed circuits use current-controlled CMOS (C3MOS) logic fabricated in conventional CMOS process technology. An entire family of logic elements including inverter/buffers, level shifters, NAND, NOR, XOR gates, latches, flip-flops and the like are implemented using C3MOS techniques. Optimum balance between power consumption and speed for each circuit application is achieve by combining high speed C3MOS logic with low power conventional CMOS logic. The combined C3MOS/CMOS logic allows greater integration of circuits such as high speed transceivers used in fiber optic communication systems.