30 results about "Colpitts oscillator" patented technology

A radio frequency identification device includes a transceiver having a resonant circuit, a rectifier, a charge pump, a state machine, and a transmitter. The resonant circuit includes an antenna and has a resonant frequency. The rectifier is coupled to the resonant circuit to provide a rectified signal in response to energy from the antenna. The charge pump is enabled in response to the rectified signal to provide a first logic signal. The state machine provides a second logic signal in response to the first logic signal. The transmitter includes an amplifier coupled to the resonant circuit to form a Colpitts oscillator that is enabled by the second logic signal to transmit a response signal for identifying the radio frequency identification device.

In wireless application there is made use of a quadrature oscillators that generate signals that are capable of oscillating at quadrature of each other. The quadrature oscillator is comprised of two differential modified Colpitts oscillators. A capacitor bank allows for the selection of a desired frequency from a plurality of discrete possible frequencies. The quadrature oscillator is further coupled with a phase-error detector connected at the point-of-use of the generated ‘I’ and ‘Q’ channels and through the control of current sources provides corrections means to ensure that the phase shift at the point-of-use remains at the desired ninety degrees.

It is described a system and a method for respiratory activity analysis comprising the use of Respiratory Inductance Plethysmography (RIP). In particular, a wearable system for extracting physiological parameters of a person by measuring at least one plethysmographic signal is disclosed. The system comprises: a wearable garment fitting a body part of the person; at least one wire supported by or embedded into the garment, each wire forming a loop around the body part when the person wears the garment for measuring a plethysmographic signal; and an electronic device supported by or fixed on the garment and including a Colpitts oscillator connected to each wire loop, wherein the Colpitts oscillator has an optimal frequency band from 1 MHz to 15 MHz for extracting the plethysmographic signal measured by each wire, the electronic device converting analog information measured by the Colpitts oscillator into digital analyzable information.

The Colpitts circuit is configured so that an equivalent capacitance of the voltage-dividing first and second capacitors connected in series through the output of the transistor amplifier is variable under the condition that the ratio of the capacitance of the first capacitor to that of the second capacitor is kept unchanged at a prescribed value. The first and second capacitors are, as a whole, configured as a matrix of elemental capacitors with 2 rows and a plural number n of columns, an array of the elemental capacitors in the first row being allotted to the first capacitor and an array of the elemental capacitors in the second row being allotted to the second capacitor. Two elemental capacitors in each column j (j=1, 2, . . . n) are connected in series and the ratio of the capacitance of the elemental capacitor corresponding to the 1j element of the matrix to the capacitance of the elemental capacitor corresponding to the 2j element has the prescribed value. The Colpitts circuit further has a first switch and a second switch allotted to each of the columns. Each of the elemental capacitors allocated to the first row is connected to the control electrode of the transistor amplifier through the first switch, and the junction of the two elemental capacitors allocated to each column is connected to the output of said transistor amplifier through the second switch. The first and second switches are operated synchronously for every column.

In wireless application there is made use of a quadrature oscillators that generate signals that are capable of oscillating at quadrature of each other. The quadrature oscillator is comprised of two differential modified Colpitts oscillators. A capacitor bank allows for the selection of a desired frequency from a plurality of discrete possible frequencies. The quadrature oscillator is further coupled with a phase-error detector connected at the point-of-use of the generated ‘I’ and ‘Q’ channels and through the control of current sources provides corrections means to ensure that the phase shift at the point-of-use remains at the desired ninety degrees.

A modulated Class E oscillator. In one embodiment, the modulated Class E oscillator may achieve high coil currents (about 1 A) and voltages (about 500 V) with low power components. Current may be injected when the oscillating current in the inductor passes through zero. A detector circuit may be used to trigger the current injection at the appropriate instant regardless of changes in the resonant frequency of the system. Its phase can be adjusted to compensate for propagation delays in the drive circuitry, while amplitude modulation is accomplished by switching in additional reactive conductance to increase the current injected into the tank circuit. Frequency modulation is accomplished in an alternate embodiment. The oscillator can also lock to an external reference signal and be phase modulated.

A differential Colpitts voltage-controlled oscillator according to example embodiments includes a feedback circuit constituting a Colpitts oscillator structure, a negative resistance circuit including a first negative resistance transistor and a second negative resistance transistor cross-coupled to each other and connected to the feedback circuit, a resonance circuit including a first inductor and a variable capacitor connected to both ends of the first inductor to generate differential output signals base on outputs of the feedback circuit, and a phase noise reduction circuit coupled to the feedback circuit to remove phase noise.

A piezoelectric-vibrator series circuit including two series-connected piezoelectric vibrators to which stresses induced by a dynamic quantity are applied in opposite directions is used, and a Colpitts oscillator circuit is defined by the piezoelectric-vibrator series circuit and an amplifier circuit / load impedance circuit. A phase-difference-to-voltage converter circuit is provided to convert a phase difference between an output voltage of the oscillator circuit and a voltage at a piezoelectric-vibrator series node of the piezoelectric-vibrator series circuit into a voltage signal.

A CMOS single-ended frequency doubler with improved subharmonic rejection and low phase noise which allows a single ended reference signal to be utilized in a Balanced Colpitts oscillator. The input is reproduced with a 180-degree phase shift for the opposite Colpitts transistor. This is achieved by adding two PMOS transistors. One transistor is placed as a follower, which reproduces any voltage shift applied to its gate to its source. Another transistor is a matching transistor for balance. By applying the single-ended signal to the gate of the follower transistor, it is reproduced at the source. The rest of the circuit takes advantage of the summing of two period currents with a 180-degree phase shift. The present invention achieves superior performance for frequency doubling due to the squaring of the gate voltage in the corresponding drain current. As a result, the double frequency component is further enhanced.

An oscillator outputs a sine wave with high purity capable of reducing phase noise. In a Colpitts oscillator circuit using a transistor as an amplifying part, a quartz-crystal resonator for waveform shaping is provided outside or inside an oscillation loop. A quartz-crystal resonator for oscillation and the quartz-crystal resonator for waveform shaping are formed, with an electrode pair and an electrode pair being provided on a common quartz-crystal piece. A separation distance between the electrode of the quartz-crystal resonator and the electrode of the quartz-crystal resonator is set large so that they are not elastically coupled, or even when they are elastically coupled, their coupling degree is weak, and an inductor causing parallel resonance with a parallel capacitance of the quartz-crystal resonator is provided.

Oscillation in which unwanted vibration (B mode) is surely suppressed while stable oscillation by principal vibration (C mode) is obtained is obtained. In a Colpitts oscillator including a piezoelectric vibrator, a transistor, and a first and second divided capacitive components, by inserting a feedback circuit formed by connecting a third capacitive component and a first inductor in series between a connection midpoint between the first capacitive component and the second capacitive component and an emitter of the transistor, inserting a second inductor in parallel with the second capacitive component, and setting the parallel resonance frequency of the second capacitive component and the second inductor in the vicinity of the oscillation frequency of the oscillator, the frequency band in which the negative resistance of the circuit side seen from the piezoelectric vibrator appears is set to a narrow band containing only a desired frequency to suppress unwanted vibration of the oscillator.

An ultra-low phase noise voltage controlled oscillator uses a single bipolar transistor Colpitts oscillator circuit and a noise-reducing negative feedback path consisting of a capacitor and a second element which may be a second capacitor, an inductor or a resistor. The negative feedback path is kept separate from any DC biasing paths in the circuit. A pair of varactor diodes are used to provide resonant frequency control.

A CMOS Balanced Colpitts oscillator which benefits from low cost CMOS technology. By overcoming the limited transconductance of CMOS transistors to permit oscillation with a crystal, the Balanced Colpitts application is expanded beyond simple VCO designs and permits crystal oscillator applications. The crystal is connected between the gates of the transistors of each Colpitts oscillator. The crystal supplies a differential frequency signal to both oscillators, which is a half period phase difference. In this way, the circuit effectively doubles the frequency signal. Further optimization is achieved by including variable capacitors in the circuit. In this way, the oscillation frequency can be adjusted by a control voltage, thus realizing a voltage controlled crystal oscillator. The present invention overcomes the challenge of adequately designing the varicaps in order to optimize the VCXO performance while not increasing the crystal load capacitance which would make the oscillation more difficult to start.

A low power balanced Colpitts oscillator circuit with improved negative resistance. The oscillator circuit comprises two cross-coupled Colpitts oscillators with a crystal oscillator connected between the two oscillators. A single current source can be used for both Colpitts oscillators since only one Colpitts needs a current source at a time. Using a single current source cuts the power consumption in half. Alternatively, a transistor in each Colpitts oscillator can act as a current source, which is turned on or off depending on the state of the Colpitts transistor. The two current sources are biased at a common level and matched to ensure the circuit remains symmetrical. An additional benefit of the present invention is that the negative resistance is directly improved.

Oscillation in which unwanted vibration (B mode) is surely suppressed while stable oscillation by principal vibration (C mode) is obtained is obtained. In a Colpitts oscillator including a piezoelectric vibrator, a transistor, and a first and second divided capacitive components, by inserting a feedback circuit formed by connecting a third capacitive component and a first inductor in series between a connection midpoint between the first capacitive component and the second capacitive component and an emitter of the transistor, inserting a second inductor in parallel with the second capacitive component, and setting the parallel resonance frequency of the second capacitive component and the second inductor in the vicinity of the oscillation frequency of the oscillator, the frequency band in which the negative resistance of the circuit side seen from the piezoelectric vibrator appears is set to a narrow band containing only a desired frequency to suppress unwanted vibration of the oscillator.

A broadband chaotic oscillation circuit comprises a radio frequency triode, a frequency selection network module, a bias module and an output module. Wherein the frequency selection network module isconnected with the base electrode of the radio frequency triode to form a Colpitts oscillator, the bias module is connected with the base electrode and the emitter electrode of the radio frequency triode, and the collector electrode of the radio frequency triode is a signal output node and is connected with the output module. The circuit is based on a Colpitts oscillating circuit, and utilizes double-resistor voltage division bias to supply power to a base electrode of a radio frequency triode. And the resonant network positioned at the base electrode and the emitter electrode is matched withthe radio frequency triode to realize generation of chaotic signals. The signal output node is located at the collector electrode, the load resistor of the output module and the inductor connected with the collector electrode in series form an RLC series resonance network, the resonance network does not affect the circuit state, the signal frequency spectrum can be improved by adjusting the resonance frequency, and then broadband signal output is achieved. The circuit has high load capacity, can generate continuous broadband chaotic signals, has flat signal frequency spectrums, and is suitablefor broadband radio frequency wireless communication.

A piezoelectric-vibrator series circuit including two series-connected piezoelectric vibrators to which stresses induced by a dynamic quantity are applied in opposite directions is used, and a Colpitts oscillator circuit is defined by the piezoelectric-vibrator series circuit and an amplifier circuit / load impedance circuit. A phase-difference-to-voltage converter circuit is provided to convert a phase difference between an output voltage of the oscillator circuit and a voltage at a piezoelectric-vibrator series node of the piezoelectric-vibrator series circuit into a voltage signal.

The invention relates to a self-adaptive steel ball sorting device based on electric eddy current testing. A steel ball sorting unit comprises two sorting rollers which are parallel. The two storing rollers are both in the step type. The electric eddy current testing unit comprises two groups of electric eddy current sensor, a colpitts oscillator, a testing circuit and a MCU microprocessor, wherein the two groups of electric eddy current sensor, the colpitts oscillator, the testing circuit and the MCU microprocessor are electrically connected. The two groups of electric eddy current sensors are arranged at the two ends of the two sorting rollers in pairs. The axes of the electric eddy current sensors and the axes of the two sorting rollers are located on the same plane. The spherical errorof steel balls reaches 0.08 micron, and the sorting efficiency can reach 15000 balls per hour; and in this way, the sorting efficiency is higher, and the diameter error rate of the steel balls is more accurate.

In a Colpitts quartz oscillation circuit, large negative resistance values are obtained in a high frequency band, and in the GHz band in particular. In a piezoelectric oscillator having a Colpitts oscillator, a voltage control circuit, and a coupling capacitor that couples the Colpitts oscillator and the voltage control circuit, an output of the voltage control circuit is feed back to a collector of the Colpitts oscillator via the coupling capacitor.

An oscillator outputs a sine wave with high purity capable of reducing phase noise. In a Colpitts oscillator circuit using a transistor (3) as an amplifying part, a quartz-crystal resonator (5) for waveform shaping is provided outside or inside an oscillation loop. A quartz-crystal resonator (1) for oscillation and the quartz-crystal resonator (5) for waveform shaping are formed, with an electrode pair (11, 12) and an electrode pair (51, 52) being provided on a common quartz-crystal piece (10). A separation distance between the electrode (11, (12)) of the quartz-crystal resonator (1) and the electrode (51, (52)) of the quartz-crystal resonator (5) is set large so that they are not elastically coupled, or even when they are elastically coupled, their coupling degree is weak, and an inductor causing parallel resonance with a parallel capacitance of the quartz-crystal resonator (5) is provided. And the quartz-crystal resonator (1) for oscillation and the quartz-crystal resonator (5) for waveform shaping can be replaced by an SAW harmonic oscillator using the same piezoelectric sheet construction.

A piezoelectric oscillator including a piezoelectric vibrator that vibrate at desired frequency; a first transistor for exciting the piezoelectric vibrator; a second transistor whose collector connects to an emitter of the first transistor, the second transistor being a base grounded type; a first capacitor connected between the emitter of the first transistor and ground; a series circuit comprising the piezoelectric vibrator and a second capacitor being connected between a base of the first transistor and an emitter of the second transistor, in which the first capacitor and a composition capacitance between base and emitter of the first transistor functions as a split capacitor for a feedback circuit of the Colpitts oscillator.

In a Colpitts quartz oscillation circuit, large negative resistance values are obtained in a high frequency band, and in the GHz band in particular. In a piezoelectric oscillator having a Colpitts oscillator, a voltage control circuit, and a coupling capacitor that couples the Colpitts oscillator and the voltage control circuit, an output of the voltage control circuit is feed back to a collector of the Colpitts oscillator via the coupling capacitor.

The invention discloses a chaotic signal generator based on a generalized memristive Colpitts oscillator, comprising a capacitor C 1 , capacitance C 2 , capacitance C 3 , inductance L, resistance R 1 , resistance R 2 , a bipolar transistor Q, and a generalized memristor M based on a memristive diode bridge. The chaotic signal generator based on the generalized memristor Colpitts oscillator of the present invention introduces the generalized memristor circuit based on the memristor diode bridge into the fourth-order Colpitts oscillator circuit, and can generate various chaotic phenomena by adjusting system parameters, so that It becomes a new type of chaotic signal generator. It has simple structure, strong stability, and remarkable chaotic characteristics, which can promote the development of chaotic systems.

The invention discloses a phase-shift processing based band-pass filtering oscillation system. The phase-shift processing based band-pass filtering oscillation system mainly comprises a signal transformation circuit, a signal amplification circuit connected with the signal transformation circuit, a band-pass filtering circuit connected with the signal amplification circuit, and a buffer circuit. The phase-shift processing based band-pass filtering oscillation system is characterized in that a phase-shift processing circuit is further arranged between the buffer circuit and the band-pass filtering circuit and comprises a phase-shift chip U1, a triode VT3, a triode VT2, a resistor R15, a polar capacitor C10 and the like, wherein one end of the resistor R15 is connected with a VCC+ pin of the phase-shift chip U1 while the other end of the resistor R15 is connected with an IN1 pin of the phase-shift chip U1, and a cathode of the polar capacitor C10 is connected with the IN1 pin of the phase-shift chip U1 after passing by a resistor R16 while an anode of the polar capacitor C10 is connected with an IN2 pin of the phase-shift chip U1. The phase-shift processing based band-pass filtering oscillation system has the advantages that by the aid of the phase-shift processing circuit, filtering stability of an oscillation circuit can be improved, and filtering incompleteness of the system due to instable voltage is avoided; meanwhile, an integrated chip LM741 which is high in sensitivity and cheap is adopted.

The present invention relates to the field of magnetoelectric conversion and sensitive technology, and the magnetic vibrator consists of a Colpitts oscillator, a non-crystalline magnet strip and a low-pass RC filter. The Colpitts oscillator contains a inductor with inside non-crystalline magnet strip made of nanometer iron base material or cobalt base material. The magnetic vibrator has simple circuit, small volume, wide operation temperature range and other advantages, and is suitable for detection of magnetic field, magnetic field strength and other quantity capable of being converted into magnetic field strength.

The invention discloses a Colpitts oscillator. The Colpitts oscillator depends on a near-zero threshold value MOS tube during oscillation starting and is designed by applying a substrate bias method or a grid bias method respectively, it is ensured that the MOS tube voltage gain required by circuit resonance is far greater than 4 according to the index response characteristic of the common-gate amplification coefficient of the near-zero threshold value MOS tube, and accordingly the Colpitts oscillator can achieve oscillation starting and oscillation maintenance under the condition of ultralow direct current input voltage and meet the requirements of a brain implant sensor.

The invention discloses a broadband injection locking frequency divider, which mainly solves the problems of narrow locking range and high power consumption in the prior art. The circuit comprises an inductance-capacitance resonant cavity, an injection transistor, a Colpitts oscillator and a switch current source. The oscillator is formed by connecting a transistor M1, a transistor M2, three capacitors and two inductors, the three capacitors form a positive feedback structure, and the two inductors isolate the positive feedback structure from the signal output end of the oscillator; the switch current source is formed by connecting a transistor M3 and a transistor M4, the transistor M3 and the transistor M4 are connected with a transistor M1 and a transistor M2 in the Colpitts oscillator so as to provide alternating conduction direct current for the Colpitts oscillator, and the Colpitts oscillator and the switch current source are both connected with a substrate biasing circuit so as to reduce power supply voltage. While the chip area is not increased, the frequency locking range of the frequency divider is widened, the direct current power consumption of the frequency divider is reduced, and the frequency divider can be applied to a chip of a radio frequency transceiver.

A CMOS single-ended frequency doubler with improved subharmonic rejection and low phase noise which allows a single ended reference signal to be utilized in a Balanced Colpitts oscillator. The input is reproduced with a 180-degree phase shift for the opposite Colpitts transistor. This is achieved by adding two PMOS transistors. One transistor is placed as a follower, which reproduces any voltage shift applied to its gate to its source. Another transistor is a matching transistor for balance. By applying the single-ended signal to the gate of the follower transistor, it is reproduced at the source. The rest of the circuit takes advantage of the summing of two period currents with a 180-degree phase shift. The present invention achieves superior performance for frequency doubling due to the squaring of the gate voltage in the corresponding drain current. As a result, the double frequency component is further enhanced.