Abstract: Embodiments disclosed herein relate to oscillators including methods of operating the same, for example for use in radio frequency circuits. In an embodiment, an oscillator has cross-coupled transistors connected between a resonant circuit and a tail circuit. The resonant circuit and tail circuit have respective supply connections for powering the oscillator with an external power supply and the cross-coupled transistors have a bias circuit coupled to respective gates of the cross-coupled transistors and arranged to bias said transistors in an active region of operation. The tail circuit has a current source, a tail capacitor and a tail resistor coupled between a common node of the cross-coupled transistors and the supply connection of the tail circuit.

Abstract: A low power relaxation oscillator circuit includes, in one embodiment, a first comparator for comparing voltages at first and second inputs, respectively, a first capacitor coupled to the first input of the first comparator, and a first circuit configured for charging the first capacitor to a first voltage. The first voltage is related to a propagation delay of the first comparator.

Abstract: A clock control circuit includes: a first buffer that receives a first pair of input clocks of multi-phase clocks, buffers and outputs the first pair of input clocks; a second buffer that receives a second pair of input clocks of the multi-phase clocks, and is controllable to buffer and output the second pair of input clocks or to output a fixed level; and a frequency multiplier that performs a logical operation on an output of the first buffer and an output of the second buffer, and outputs a first pair of output clocks or a second pair of output clocks as an output clocks, the first pair of output clocks is based on a frequency which is obtained by multiplying frequencies of the multi-phase clocks, and the second pair of output clocks is based on the same frequencies as the multi-phase clocks.

Abstract: A digital fractional frequency divider for fractionally dividing a digital frequency signal can include a plurality of clock division counter modules, a plurality of sampling modules, and a summing module. The plurality of clock division counter modules can each receive an input clock signal that is phase-shifted from a remaining plurality of input clock signals. Each clock division counter module can generate a long periodic pulse from the received input clock signal. Each sampling module can couple to an output of one of the plurality of clock division counter modules and can generate a short periodic pulse from the long periodic pulse. The summing module can sum the plurality of short periodic pulses to generate a fractional frequency clock signal.

Abstract: A frequency multiplier includes a first impedance module, a second impedance module, a first path and a second path. When the first path is conducted, the first impedance module generates a first output signal and the second impedance module generates a second output signal. When the second path is conducted, the first impedance module generates a third output signal and the second impedance module generates a fourth output signal. The first and second paths are not conducted simultaneously. A frequency of a first combination signal generated from the first and third output signals and a frequency of a second combination signal generated from the second and fourth output signals are N times of a frequency of the input signal, where N is a positive rational number.

Abstract: A signal processor includes: a plurality of frequency converters which perform frequency conversion of input signals to output converted signals; and an output section which combines the converted signals output from the plurality of frequency converters and outputs a composite signal, wherein the plurality of frequency converters are formed in a one-chip semiconductor chip, and the plurality of frequency converters perform frequency conversion into converted signals in different frequency bands.

Abstract: A frequency multiplier includes a first impedance module, a second impedance module, a first path and a second path. When the first path is conducted, the first impedance module generates a first output signal and the second impedance module generates a second output signal. When the second path is conducted, the first impedance module generates a third output signal and the second impedance module generates a fourth output signal. The first and second paths are not conducted simultaneously. A frequency of a first combination signal generated from the first and third output signals and a frequency of a second combination signal generated from the second and fourth output signals are N times of a frequency of the input signal, where N is a positive rational number.

Abstract: A circuit includes an oscillation generation circuit, a distribution circuit, and a transceiver circuit. The oscillation generation circuit is configured to generate a first oscillation signal having a first frequency. The distribution circuit includes a voltage to current stage, a transmission portion and a current to voltage stage. The voltage to current stage is configured to receive the first oscillation signal, and convert the first oscillation signal into a current form. The transmission portion is configured to transmit the first oscillation signal in the current form. The current to voltage stage is configured to receive the first oscillation signal in the current form and generate a second oscillation signal having a sub-harmonic frequency of the first frequency, such as half of the first frequency. The transceiver circuit is configured to operate in a frequency band responsive to the second oscillation signal.

Abstract: According to one embodiment, there is provided a DLL circuit including a delay chain, a plurality of phase comparators, and a controller. The plurality of phase comparators receive the reference clocks individually and receive respectively the clocks from the delay elements in mutually different stages, among the delay elements of the plurality of stages. The controller simultaneously receives comparison results of the plurality of phase comparators, determines the number of stages that generate the clock of which a phase is synchronized with a phase of the reference clock from among the delay elements of the plurality of stages, and selects the number of output stages from among the delay elements of the plurality of stages based on the determined number of stages so that a delay clock having a demanded delay amount with respect to the reference clock is output.

Abstract: Disclosed is a harmonic rejection mixer that makes it possible to suppress high-frequency response, while keeping the number of gm elements from increasing. In a harmonic rejection mixer that regulates the waveform of an output signal by mixing outputs of multiple mixers that are connected in parallel with the latter stage of multiple gm elements, some of the gm elements are shared by I phase and Q phase by using a control signal with a duty ratio of less than 50% to drive at least some of the mixers, and then using the period in which the I-phase mixers are inactive to activate the Q-phase mixers.

Abstract: A divider has a clock generation circuit which combines a first trigger clock and a second trigger clock having a first phase difference, so as to generate a third clock having pulse edges corresponding to pulse edges of the first trigger clock and the second trigger clock; an output dividing circuit which divides the frequency of the third clock in half so as to generate a first differential output clock and a second differential output clock having a duty ratio corresponding to the first phase difference; and a phase correction circuit which detects a phase of the first output clock or the second output clock at a timing of the pulse edge of the first trigger clock or the second trigger clock, so as to generate a phase correction signal for resetting the output dividing circuit when the detected phase is not a normal phase.

Abstract: An apparatus includes an injection locking frequency divider, which includes a first resonant tank that has a first resonance frequency and a common mode path that includes a second resonant tank, and has a second resonance frequency that is a harmonic of the first resonance frequency. The second resonant tank is adapted to receive a first signal having an oscillation frequency near the harmonic of the first resonance frequency to cause the first resonant tank to provide a second signal that is locked to the first signal.

Abstract: A divider of an input multiphase signal by a given division factor so as to obtain an output multiphase signal, the divider having a circuit adapted to divide a first signal component of an input multiphase signal by an given division factor to obtain a first component of a output multiphase signal, and a plurality of N?1 devices including a first device adapted to sample the first component with a component of the input multiphase signal to obtain the component of the output multiphase signal corresponding to the one component of the input multiphase signal. Every other device of the plurality of N?1 devices is adapted to sample the component of the output multiphase signal of the preceding device with another component of the input multiphase signal, phase shifted by a further constant factor to obtain the corresponding component of the output multiphase signal.

Abstract: The present invention provides a method for identifying a specific number of communicating points having relatively smallest accumulated path values from a plurality of transmitting points for a receiving point in a communication system. The method includes steps of: (a) defining a first coordination of each of the plurality of transmitting points and the receiving point on a complex plane; (b) transferring the first coordination of the receiving point to a second coordination thereof, in which the second coordination of the receiving point is near an origin of the complex plane; and (c) identifying the specific number of transmitting points having relatively smallest accumulated path values based on the second coordination of the receiving point.

Abstract: A high-order harmonics generator includes a plurality of high-pass filters to block out DC signals. In one embodiment, high-pass filters are coupled to the output signals from an envelope detector and a power detector. A high-pass filter can also be coupled to the output of a multiplier that multiplies the filtered envelope signal and the filtered power signal. Additional multipliers may also be used at outputs of multipliers in a cascaded chain of multipliers for higher harmonics generation.

Abstract: Embodiments of the present invention provide a current mode logic circuit, comprising first and second differential switching stages, each stage arranged being arranged to receive a plurality of clock signals, such that the first and second differential switching stages respond to a combination of the plurality of clock signals.

Abstract: A semiconductor integrated circuit is provided in which the timing margin for fetching data is prevented from being reduced even in the case where the duty ratio of a clock signal is different from 50%. The semiconductor integrated circuit includes: a clock input terminal for receiving a clock signal; a data input terminal for receiving a data signal; internal clock generating circuits for generating an internal clock signal which is switched at an intermediate timing between the i-th (i: an integer of 1 or larger) switch timing and the (i+1)th switch timing of the clock signal; and a latch circuit for latching the data signal synchronously with the internal clock signal. An internal clock signal which is switched at an intermediate timing between the i-th switch timing and the (i+1)th switch timing of the clock signal is generated, and the data signal is fetched synchronously with the internal clock signal.

Abstract: Various embodiments provide a Phase Interpolator (PI) that receives input clocks, and outputs intersymbol interference-equalized, phase-shifted output clocks. In one embodiment, the Phase Interpolator comprises two PI Conditioners and a PI Mixer. In one embodiment, a PI Conditioner receives input clocks and is controlled by a different phase-shifted input clock by using a suitable circuit element, such as a flip-flop. Collectively, the input clock-controlled PI Conditioner and Mixer act in concert to control the band limiting effect of the PI Conditioner which, in turn, equalizes intersymbol interference.

Abstract: A circuit is provided for multiplying a frequency by a cascade formed of a transadmittance having a transfer characteristic and a transimpedance having a transfer characteristic. The transadmittance includes two terminals for a signal of a first frequency and the transimpedance includes two terminals for a signal of a second frequency. A transfer characteristic of the transimpedance is steeper than a transfer characteristic of the transadmittance, and a modulation region of the transadmittance is larger than a modulation region of the transimpedance.

Abstract: A signal generating circuit includes a relaxation oscillator operating to alternately generate a first ramp signal that is periodic at a frequency of the relaxation oscillator and a second ramp signal that is periodic at the frequency of the relaxation oscillator and is out of phase with respect to the first ramp signal The first ramp signal is compared to a first reference voltage and the state of a first flip-flop is changed if the first ramp signal exceeds the first reference voltage. The second ramp signal is compared to the first reference voltage and the state of a second flip-flop is changed if the second ramp signal exceeds the first reference voltage. The first flip-flop is reset in response to a first level of the first ramp signal and the second flip-flop is reset in response to a second level of the second ramp signal.

Abstract: A clock multiplication circuit simple in configuration, easy to adjust the characteristics thereof, and capable of shortening lockup time. The circuit delivers an output clock signal at a frequency that is a multiple of the frequency of a reference clock signal as inputted. A counter counts the number of rising edges of the output clock signal existing during a High level period of the reference clock signal, delivering a count value CN. A subtracter subtracts the count value from a reference value BN, delivering a difference value DN. An adder adds the difference value to a preceding integrated value, calculating a new integrated value. A DA converter delivers the analog control voltage corresponding to the integrated value. A VCO delivers the output clock signal at a frequency corresponding to the analog control voltage. The frequency of the output clock signal is controlled such that DN=BN?CN=0.

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 apparatus for generating quadrature phase signals in a half-rate data recovery circuit, which is adapted to generate a first and a second clock signals having the same frequency and being 90 degrees out of phase with each other. The apparatus for generating quadrature phase signals mainly comprises a base selector, a first phase interpolator and a second phase interpolator. The base selector generates, based on a region control signal, a pair of phase region boundaries for the first clock signal as well as a pair of phase region boundaries for the second clock signal by using a plurality of reference clock signals. The first and second phase interpolators perform, based on a position control signal, weighted average processes for the two pairs of phase region boundaries, respectively, to thereby obtain the first and the second clock signals.

Abstract: An electronic device which includes a periodic signal generator (12) and a frequency multiplier circuit (14) for multiplying the frequency of the periodic signal. The multiplier circuit is formed on the basis of an EXCLUSIVE-OR gate (20), which receives the periodic signal, and a frequency divider circuit (22) connected between the output and an input of the gate. From this divider circuit it is possible to derive in a very simple way quadrature signals, which makes it feasible to perform a modulation of the type known as “zero demodulation”. The multiplier circuit can operate in accordance with CML technology (Current Mode Logic).

Abstract: A clock control circuit which includes a frequency multiplying interpolator for generating and outputting multiphase clocks by frequency multiplying an input clock; a switch for outputting two of the multiphase clocks input thereto from the frequency multiplying interpolator; a fine adjusting interpolator, to which the two outputs from the switch are applied, for outputting a signal obtained by internally dividing the phase difference between the two outputs; and a control circuit for controlling the switching of the switch and varying the internal-division ratio of the fine adjusting interpolator.

Abstract: A bipolar analog multiplier with a greatly reduced output sensitivity to temperature. The multiplier uses the difference between the multiplier input voltages and the reference voltages to generate currents. Voltages which are logarithmically dependent on the generated currents are developed and applied to inputs of bipolar variable transconductance stages. Circuits are used to reduce ringing at the output of the multiplier.

Abstract: A phase shifter is provided between common emitters of two differential transistor pairs of a mixer circuit. The phase shifter changes the phase of a voltage signal input to one common emitter by 180.degree. and applies it to the other common emitter, and causes a current in accordance with the voltage between the common emitters. As compared with the prior art employing two stages of vertically connected differential transistor pairs, the power supply voltage can be reduced.

Abstract: A semiconductor operational circuit conducts real-time analog vector operations to permit the determination of the center of gravity of an image of a moving object. The circuit employs a first processing stage utilizing CMOS source follower circuits to perform weighted linear sum operations on the analog signals. A second processing stage utilizes comparator circuitry to perform comparison operations involving data from the weighted-sum and non-weighted-sum operations. A third processing stage utilizes exclusive OR gates to provide digital data outputs based on the comparison operation results.

Abstract: A clock frequency multiplier with a rise detector flip-flop connected to a series of buffers having interspersed parallel output taps connected to a binary to Gray converter for providing real time rise status indications. The parallel tap outputs are connected to first, second and third multiplexers, to produce first and second fall outputs and a second rise output. The multiplexers are controlled by first, second and third corresponding tap circuits having hexadecimal inputs from a Gray to hexadecimal converter connected to the output of the binary to Gray converter through a flip-flop clocked by a second rise of the input clock signal.

Abstract: A differential circuit is provided, which makes it possible to realize an ideal linear behavior with respect to an input signal. This circuit includes a voltage-current converter, a current-voltage converter, and a triple-tail cell. The voltage-current converter converts an initial input voltage to generate first and second differential output currents. The current-voltage converter converts the first and second output currents to generate first and second output voltages. The triple-tail cell has first, second, and third transistors driven by a common constant current. The first and second transistors form a differential pair. The first and second output voltages are differentially applied across input ends of the differential pair. The third transistor serves as a bypass transistor for the common constant current. An input end of the third transistor is applied with a bias voltage. An output current of the differential circuit is derived from output ends of the differential pair.

Abstract: A four quadrant multiplier using multiple input floating-gate MOS transistors is provided. It is based on the square law characteristics of the MOS transistor and can be realised with only four floating gate MOS transistors, two resistors and a current source. The four floating gate transistors are configured with their sources connected in common and biased by a single current source. Output is taken between two common drain connections. Each transistor has three control gates with two being provided for selected ones of the two input signals and one for a biasing signal (optional). Input signals can be connected to the control gates in either a differential or single ended configuration. In one application, a programmable synaptic cell for neural networks employs the multi-input floating-gate MOS four-quadrant analog multiplier. Varying of the neural weight connection strength of each synaptic cell is achieved by two possible methods.

Abstract: A frequency multiplication circuit (10) includes a periodic interval selector (12) and a delay element (28) to produce an output signal (26) in phase with, and at a frequency multiple of a reference signal (18). During a first time interval, the periodic interval selector (12) bases the output signal (26) on the reference signal (18). During a second time interval, the periodic interval selector (12) bases the output signal (26) on a delayed signal (22) produced by the delay element (14) based upon the output signal (26). Feedback from the output of the periodic interval selector (12) through the delay element (14) and the operation of the periodic interval selector (12) causes the output signal (26) to be in phase with, and at a frequency multiple of the reference signal (18). Delay adjuster (52) adjusts delay produced by the delay element (14) to adjust the output signal (26) to cause the output signal (26) to have a desired duty cycle consistency.

Abstract: A multi-channel carrier wave generator includes a signal source capable of generating a carrier wave having a frequency, a first input-match diode circuit receiving the carrier wave to correspondingly generate a plurality of harmonic waves, a first multi-way power divider electrically connected to the first input-match diode circuit to equally divide the harmonic waves, and a first multi-way filter electrically connected to the first multiple power divider to filter through the harmonic waves. Such a multi-channel carrier wave generator has the advantages of having a simple fabrication procedure, a low cost, and a low phase noise, and capable of providing a stable carrier wave and a good filtering result and of using a lower order bandpass filter.

Abstract: A circuit for generating a pair of quadrature output signals from a pair of quadrature input signals in which the frequency of the output signals is double that of the input. The circuit consists of two dual phase shifters, two symmetrical multipliers and a phase controller. The circuit is fabricated by conventional integrated circuit processing technology. A method of generating frequency doubled quadrature output signals is disclosed.