130results about How to "Improve noise figure" patented technology

A modified derivative superposition (MDS) low noise amplifier (LNA) includes a main current path and a cancel current path. Third-order distortion in the cancel path is used to cancel third-order distortion in the main path. In one novel aspect, there is a separate source degeneration inductor for each of the two current paths, thereby facilitating tuning of one current path without affecting the other current path. In a second novel aspect, a deboost current path is provided that does not pass through the LNA load. The deboost current allows negative feedback to be increased without generating headroom problems. In a third novel aspect, the cancel current path and/or deboost current path is programmably disabled to reduce power consumption and improve noise figure in operational modes that do not require high linearity.

Continuous variable-gain low-noise amplifier. The amplifier continuously adjusts its gain between well-defined high and low values by using a cascode current-steering circuit to partition signal current between two different nodes of an output loading network. A shunt feedback network connected from an intermediate node of the loading network to the input provides negative feedback that linearizes the amplifier as its gain is decreased. The circuit degrades the noise figure at lower gains by varying the gain without directly dumping the signal current to the power supply. The circuit produces only small changes in input and output impedances and preserves an improved reverse-isolation cascode characteristic as the gain is controlled.

The present invention is directed to a highly-integrated MEMS-based miniaturized transceiver. The transceiver utilizes a low band front-end to direct sample low band signals and a high band front-end to translate high band signals that cannot be directly sampled to low band before low band front-end processing. The low band front-end comprises an array of High-Q MEMS (microelectromechanical systems)-based filters/resonators separated by isolation amplifiers in selectable cascade with narrower bandwidth filters. Dynamic tuning ability is provided through the isolation amplifiers and the sample frequency of the analog-to-digital converter. This architecture is amenable to monolithic fabrication. The input frequency range is scalable with analog-to-digital conversion sampling rate improvements. Re-utilization of filters is spatially efficient and cost effective. Tuning time is limited only by the analog-to-digital conversion and digital signal processing, not synthesizer settling times. This architecture eliminates major sources of traditional intermodulation distortion and reduces complex hardware, increasing reliability.

The variable gain amplifier includes a bias circuit (BC) 1, a matching circuit (MC) 2, a variable gain resistive feedback amplifier (FA) 3 and an output follower (EA) 4. The resistance values of the load resistance Rc and feedback resistance Rf are changed in cooperation. In a case of making the load resistance Rc a high resistance to set the low noise amplifier to a high gain, the feedback resistance Rf is also made a high resistance, the feedback time constant τfb(c1)≈2π·RfCbe/(1+gmRc) of the closed loop of the resistive negative feedback amplifier 3 becomes substantially constant, and then the amplifier has a gain small in frequency dependency over a wide bandwidth. In a case of making the load resistance Rc a low resistance to set the low noise amplifier to a low gain, the feedback resistance Rf is also made a low resistance. The feedback resistance Rf with the low resistance increases the negative feedback quantity, and thus the amplifier is set to a low gain. Also, the load resistance Rc is made a low resistance, and the feedback time constant τfb(c1) becomes substantially constant. The gain is not lowered further in a high frequency region.

A silicon and silicon germanium based semiconductor MODFET device design and method of manufacture. The MODFET design includes a high-mobility layer structure capable of ultra high-speed, low-noise for a variety of communication applications including RF, microwave, sub-millimeter-wave and millimeter-wave. The epitaxial field effect transistor layer structure includes critical (vertical and lateral) device scaling and layer structure design for a high mobility strained n-channel and p-channel transistor incorporating silicon and silicon germanium layers to form the optimum modulation-doped heterostructure on an ultra thin SOI or SGOI substrate capable of achieving greatly improved RF performance.

The invention discloses a single-ended input and differential output parallel dual-frequency low noise amplifier (LNA) and a design method thereof. The LNA can be applied to a digital TV, wireless communication and a navigation receiver and mainly comprises an input matching network, a main amplification circuit, an output network and a single-ended to differential circuit. The main amplification circuit adopts a cascode structure and has favorable reverse isolation degree; the input matching network enables the LNA to realize impedance matching and noise matching simultaneously in input stage and dual frequency ranges, and thus the noise performance of the circuit is improved at the same time of ensuring the maximum power transmission; and the singled-ended to differential circuit ensures that the LNA can be directly cascaded with a front-end antenna and a rear-end mixer circuit and easy to integrate. The LNA disclosed by the invention not only has a simple design, but also ensures that the system power consumption and area are reduced due to parallel dual-frequency receiving.

Tuners with high input impedance are connected to a common radio frequency (RF) signal source. A termination load external to the tuners provides matched impedance loading for the transmission line or cable driving the tuners. Alternatively, the termination load can be located inside one tuner with a switch to enable or disable the load. All tuners receive the same signal and no signal degradation is caused when connecting multiple tuners. The multiple tuner connection is useful in television signal receiving devices that receive more than one independent channel, such as digital video recorders or picture-in-picture television receivers.

A front end circuit for coupling an antenna to a radio frequency (RF) transceiver is disclosed. An antenna port connectible to the antenna is provided, as well as a power amplifier coupled to a signal output of the RF transceiver and a low noise amplifier coupled to the signal input of the RF transceiver. The front end circuit includes a switching network that is connected to the antenna port, the power amplifier, and the low noise amplifier. Additionally, there is at least one resonant circuit and a control circuit coupled to a receive enable line of the transceiver. This resonant circuit defines a parallel resonance with a first resonant resistance in the operating frequency band upon activation in the receive mode. The resonant circuit also defines a substantially high transistor impedance upon deactivation in the transmit mode.

Disclosed herein is an amplifier circuit having improved linearity and frequency band using a MGTR. The amplifier circuit comprises an amplification unit including a main transistor and an auxiliary transistor, an attenuation unit including inductors respectively connected to the source of the main transistor and the source of the auxiliary transistor, a capacitor connected at one end thereof to the sources of the main transistor and auxiliary transistor and connected at the other end thereof to the gates of the main transistor and-auxiliary transistor, and an output unit connected to the drains of the main transistor and auxiliary transistor.

The invention relates to a comb spectrum generation system based on a cyclic frequency shift pattern and an application method of the comb spectrum generation system based on a cyclic frequency shift pattern. The comb spectrum generation system based on the cyclic frequency shift pattern comprises an external-cavity semiconductor laser, a 3 dB coupler, a polarization controller, an intelligence quotient (IQ) modulator, a phase modulator, an optical frequency spectrum analyzer, a cosine microwave signal source, a phase shifter, an erbium-doped optical fiber amplifier, an optical filter, an adjustable optical delay line, a direct current bias supply and a section of optical fiber. Cosine radio-frequency signals, reversed cosine radio-frequency signals, sine radio frequency signals with same frequency, and reversed sine radio frequency signals with same frequency are inputted into the IQ modulator. Down-converted signals of optical carrier can be produced through adding appropriate bias voltage to a direct current electrode. The down-converted frequency is four radio frequency (RF) electrode incoming frequency. Elements of coupled seed light and the down-converted light of the optical carrier are modulated by the IQ modulator in a loop circuit. Flat comb spectrum can be obtained through reasonable gain conditions of the erbium-doped optical fiber amplifier and choices of the optical carrier bandwidth.

The invention discloses a low noise amplifier for current reuse and noise cancellation. The amplifier comprises a common-source amplifier, a common-gate amplifier, a signal isolation and current reuse network and an off-chip receiving network, wherein the common-source amplifier comprises a first N-type metal oxide transistor, a first resistor, a third resistor, a first capacitor and a sixth capacitor; the common-gate amplifier comprises a second N-type metal oxide transistor, a second resistor, a second capacitor and a fifth capacitor; the signal isolation and current reuse network comprises a first resonant network and a second resonant network; the first resonant network consists of a first inductor and a third capacitor; the second resonant network consists of a second inductor and a fourth capacitor; and the off-chip receiving network comprises a second inductor, a signal source of an artificial antenna and an antenna internal resistor. The low noise amplifier in such a structure has a noise cancellation function and simultaneously reuses the static bias current of the common-gate amplifier and the common-source amplifier, thereby having a low noise coefficient and a low power consumption function.

The invention relates to a variable gain amplifier comprising a first attenuator (1) for receiving an input signal (rf_in) and for transmitting a first attenuated input signal to a first amplifier (2) for amplifying the first attenuated input signal and for generating a first amplified signal to a second attenuator (3) for attenuating the first amplified signal and for transmitting a second attenuated signal to a second amplifier (4) for amplifying the second attenuated signal and for generating an output signal (rf_out). The first attenuator (1) is supplied from a first supply voltage source (10). The second attenuator (3) is supplied from a second supply voltage source (30). The first amplifier (2) is supplied from a third supply voltage source (20), and the second amplifier (4) is supplied from a fourth supply voltage source (40).

Optical systems of the present invention include first and second optical amplifiers that are operated individually to provide gain profiles that do not conform with a desired composite, or overall or total, gain profile, e.g., substantially flat, but to produce a desired composite noise figure profile, e.g., substantially flat or otherwise, for the amplifiers. Generally, the desired composite noise figure profile is produced, while attempting to minimize the deviation of the composite gain profile from the desired composite gain profile.

The invention relates to the field of wireless communications, in particular to a wireless communication network optimization device, which comprises a donor antenna, an outdoor signal amplification system, a control module, an indoor signal amplification system and a retransmission antenna. The donor antenna is used for receiving a weak outdoor wireless communication signal and retransmitting an indoor mobile phone user signal after processing of the network optimization device; the outdoor signal amplification system is used for amplifying the power of the received weak outdoor wireless communication signal; the indoor signal amplification system is used for amplifying the power of the received mobile phone user wireless communication signal; the retransmission antenna is used for transmitting an outdoor wireless communication signal after processing of the network optimization device and receiving the mobile phone user wireless communication signal; and the control module is used for controlling operation of the donor antenna, the outdoor signal amplification system, the indoor signal amplification system and the retransmission antenna. The device has the advantages of low manufacturing cost and simple installation.

The invention relates to a low-noise amplifier for bioelectricity detection. The low-noise amplifier comprises an input chopper circuit (1), an input coupling capacitor module (2), a two-stage operational amplifier module (3), a capacitance negative feedback loop (4), a positive feedback input impedance lifting loop (5) and an electrode direct-current offset elimination loop (6). According to thelow-noise amplifier, the noise coefficient of the low-noise amplifier is improved by adopting the two stages of operational amplifier modules for current multiplexing; the noise performance of the low-noise amplifier is further improved, meanwhile, the direct-current offset voltage between electrodes in the analog front-end circuit is restrained through the electrode direct-current offset eliminating loop, and therefore the quality of signals received by the analog front-end circuit is guaranteed.