57 results about "Active mixer" patented technology

A mixer is disclosed that includes first and second transconductance modules that, in one embodiment, includes MOSFETs configured to receive a plurality of signals that are to be mixed and a selectively coupled auxiliary current source to inject an auxiliary current into the second transconductance module approximately at or near a zero-crossing point in order to reduce flicker noise and other noise introduced into an output signal during switching. Accordingly, as a first transconductance module approaches a zero-crossing, auxiliary current is injected to reduce the current produced therefrom thereby reducing flicker noise. In a differential mixer, the amount of current produced from a transistor pair to which the signal cycle is being switched is also reduced thereby reducing noise from the transistor pair that is turning on for the next portion of a signal cycle.

The present invention relates generally to communications, and more specifically to a method and apparatus for minimizing DC offset and second-order modulation products (IM2 noise) while demodulating RF signals. The principle of the invention can be applied to differential, down-conversion circuits (50) consisting of two differential mixers (54, 56) in series, a follows: a pair of current sources Ia and Ib are used to provide current to positive and negative channels of the first differential mixer (54). Providing current to the amplifying transistors of the first mixer (54) reduces the current drawn through the active mixer switches, reducing the noise generated. The current sources 1a and 1b are trimmed in a complementary manner where 1a=I+Delta1, and 1b=Delta1. The value of Δ1 can be determined in a number of manners; for example, it could be established by testing after the circuit has been fabricated, and the value stored on-chip, for future use.

This invention relates to a micromachined microfluidics diagnostic device that comprises one or multiple assaying channels each of which is comprised a sample port, a first valve, a reaction chamber, a second valve, a fluid ejector array, a third valve, a buffer chamber, a capture zone and a waste chamber. Each of these device components are interconnected through microfluidic channels. This invention further relates to the method of operating a micromachined microfluidic diagnostic device. The flow of fluid in the microchannels is regulated through micromachined valves. The reaction of sample analytes with fluorescent tags and detection antibodies in the reaction chamber are enhanced by the micromachined active mixer. By ejecting reaction mixture onto the capture zone through micromachined fluid ejector array, the fluorescent tagged analytes bind with capturing antiodies on capture zone. The fluid ejector array further ejects buffer fluid to wash away unbound fluorescent tags.

The invention provides an adjustable negative resistance structure-based multimode multi-channel mixer, which comprises a radio frequency input circuit, an adjustable negative resistance circuit, a digital control capacitor array circuit and a double-balanced differential structure circuit, wherein two input ports of the radio frequency input circuit are connected with radio frequency signals RF+ and RF-, and an output port of the radio frequency input circuit is directly connected with ports RFout+ and RFout-; the negative resistance size of the adjustable negative resistance circuit is controlled by two levels Vctrll and Vctrl, and an output end of the adjustable negative resistance circuit is connected with the RFout+ and the RFout-; an input port of the digital control capacitor array circuit is controlled by a digital signal, and two output ports of the digital control capacitor array circuit are connected with the RFout+ and the RFout-; and radio frequency current signals are input into the double-balanced differential structure circuit through the RFout+ and the RFout-, and are mixed with local oscillation signals LO+ and LO- to output intermediate-frequency signals IF+ and IF- to be then input into a rear-end module. By the adjustable negative resistance circuit, the equivalent parallel resistance of a capacitor array is eliminated, a noise coefficient is reduced, the gain of an active mixer is improved, the working frequency of the mixer can be controlled by a digital end, and the requirements of a broadband multi-channel system are met.

The present invention provides a semiconductor integrated circuit including an active mixer circuit that is operated at low voltage, low noise, and low power consumption. It includes a transconductance amplifier, a transformer, and a multiplier, connects a transformer between the transconductance amplifier and the multiplier, and separates between the transconductance amplifier and the multiplier with respect to direct current inside the transformer. Further, each of the tranconductance amplifier and the multiplier is configured of transistors that are single-stacked between the supply voltage terminal and ground terminal.

Integrated circuit including a mixer circuit, which has a first circuit section, a second circuit section, and a transformer. The first circuit section has two radiofrequency terminals. The second circuit section has two reference oscillator terminals, an active mixer unit with a signal-amplifying unit, and two intermediate frequency terminals. The active mixer unit and the signal-amplifying unit have a common current path. The transformer directly electrically decouples the two radiofrequency terminals from the active mixer unit, and couples the first circuit section and the second circuit section together such that each of the two circuit sections is separately supplied with a full operating voltage of the integrated circuit. The integrated circuit may additionally include a second transformer connected between the active mixer unit and the two intermediate frequency terminals.

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.

There is provided a switching circuit for an active mixer. The switching circuit comprises a first pair of parallel switching devices and a second pair of parallel switching devices. The first and second pairs of parallel switching devices are arranged in a stacked configuration between an input node at which an input current comprising a first input frequency signal is received and a pair of differential output nodes. The first pair of switching devices are controlled by a second input frequency signal. The second pair of switching devices are controlled by a phase-shifted counterpart of the second input frequency signal. A common node between the first switching devices of the first and second pairs of switching devices is electrically coupled to a common node between the second switching devices of the first and second pairs of switching devices.

The present disclosure discloses an active mixer capable of improving linearity while giving consideration to both gain and noise reduction, including: a voltage-to-current converting circuit operable to generate a conversion signal according to an input signal; a switching circuit operable to carry out a switching action according to a clock signal and thereby electrically connect the voltage-to-current converting circuit with a load circuit; the load circuit operable to provide an output signal for a first and a second output nodes according to the conversion signal through the switching action; a first supplement current source, coupled to a first node between the switching circuit and the first output node, operable to supply a first supplemental current to the switching circuit; and a second supplement current source, coupled to a second node between the switching circuit and the second output node, operable to supply a second supplemental current to the switching circuit.

An active mixer with self-adaptive bias feedback is described and resolves a poor linearity, inconvenient design of a bias circuit, and other defects of a conventional mixer. The dual self-feedback bias structure according to this invention is used. The active mixer with self-adaptive bias feedback has a power supply, an RF input match / drive unit, a local oscillator input match / drive unit, a mixer core unit, a self-adaptive twin bias circuit and an IF output match / buffer unit. This invention improves the linearity of a conventional mixer and does not affect other characteristics. There are fewer components in this invention; an area of the mixer is thus smaller. Further, this invention may improve temperature response, increase yield factor, and lower unit cost. The dual self-feedback bias structure is designed for further application to other semiconductor manufacturing processes, components, and microwave products.

An oscillator is provided that is arranged to function as a simplified receiver. The oscillator has a resonator portion and a non-linear portion, which cooperate to generate an oscillating signal. The resonator portion is positioned to receive a modulated signal. In one configuration, the oscillator operates at a frequency offset from the frequency of the carrier for the modulated signal. In this simple arrangement, the oscillator functions as an active mixer, and generates a product output signal. The output signal is extracted from a high impedance point of the oscillator's non-linear device. The output signal is a demodulated or mixed signal, and may be further processed to detect a data signal.

A transmitter RF front-end integrated on a single substrate is enabled to determine whether associated IF amplification stage provides a required transmission gain for transmitting an output signal of an application. A dedicated power amplifier driver within the transmitter RF front-end is configured to provide additional gain, when needed based on the determination, to meet the required transmission gain for transmitting the output signal. The associated IF amplification stage comprises an upconversion mixer and a lowpass filter (LPF). The upconversion mixer may be implemented as an active mixer or a passive mixer. The upconversion mixer and the dedicated power amplifier driver are enabled to operate in 2.44 gigahertz. A maximum gain provided by the associated intermediate frequency (IF) amplification stage for transmitting the output signal is determined to decide the additional gain provided by the dedicated power amplifier driver by comparing with the required transmission gain.

There is provided a switching circuit for an active mixer. The switching circuit comprises a first pair of parallel switching devices and a second pair of parallel switching devices. The first and second pairs of parallel switching devices are arranged in a stacked configuration between an input node at which an input current comprising a first input frequency signal is received and a pair of differential output nodes. The first pair of switching devices are controlled by a second input frequency signal. The second pair of switching devices are controlled by a phase-shifted counterpart of the second input frequency signal. A common node between the first switching devices of the first and second pairs of switching devices is electrically coupled to a common node between the second switching devices of the first and second pairs of switching devices.

The invention relates to a single-balanced active mixer that can work at a low power voltage. The active mixer comprises an alternating current coupling capacitor C0 of a radio frequency (RF) input signal (Vrf), a direct current bias resistor R0, an input tube N1 and a bias tube N0 thereof, and also comprises a metal oxide semiconductor (MOS) tube N2, an MOS tube N3, an MOS tube P2 and an MOS tube P3 that are used as loads. The N2 and P2 are connected to a positive local oscillator signal (Vlop) through capacitors C2 and C3. The N3 and P3 are connected to a negative local oscillator signal (Vlon) through capacitors C4 and C5. A P0 provides direct current bias for grids of load tubes P2 and P3. A resistor R1 provides bias for grids of the load tubes N2 and N3, and the bias resistor R1 and the bias tube N0 are in the same current path, so that the bias voltages of the N2 and N3 are slightly higher than that of the N1. Through adoption of the active mixer, the problem that the existing active mixer is hard to work at an extreme low voltage is solved, and the active mixer has lower power consumption.

A wideband mixer includes a core mixer having input terminals and output terminals for, respectively, receiving differential input signals and providing amplified differential output signals. A steering module is coupled to the core mixer for receiving differential reference signals and providing bi-phase modulated amplified differential output signals. The core mixer is configured to provide a value of gain between the differential input signals and the differential output signals. A bandwidth peaking network is coupled to the core mixer and includes (a) a first coil and a first resistor connected in series and (b) a second coil and a second resistor connected in series. The first coil and resistor and the second coil and resistor, respectively, are coupled to the core mixer for receiving the amplified differential output signals. The bandwidth peaking network is configured to increase the frequency bandwidth of the core mixer.