122 results about "High gain amplifier" patented technology

An automatic gain control (AGC) amplifier including a high gain transimpedance amplifier, a resistive feedback network and multiple transconductance stages coupled in the feedback path of the AGC amplifier. The feedback network receives an input signal and is coupled to the output of the high gain amplifier and has multiple intermediate nodes. Each transconductance stage has an input coupled to an intermediate node of the feedback network and an output coupled to the input of the high gain amplifier. Each transconductance stage is independently controllable to position a virtual ground within the feedback network to control closed loop gain. Each transconductance stage may have a bias current input coupled to a bias current control circuit. The control circuit controls each bias current to vary the gain of the AGC amplifier. The bias currents may be linearly controlled employing a ramp function to achieve a linear in dB gain response.

An automatic gain control (AGC) circuit including a high gain amplifier, a feedback network and two transconductance amplifiers. The feedback network has a first end that receives an input signal of the AGC circuit, a second end coupled to the output of the high gain amplifier and two intermediate nodes. Each transconductance amplifier has an input coupled to a respective intermediate node of the feedback network and an output coupled to the input of the high gain amplifier. The transconductance amplifiers collectively control a position of a virtual ground within the feedback network to control gain of the AGC circuit. The transconductance amplifiers each include an attenuator and a transconductance stage coupled between the feedback network and the high gain amplifier and are configured to operate linearly across a relatively wide input voltage range. The input offset voltage of the AGC circuit varies monotonically with gain of the AGC circuit.

A receiving circuit of a direct conversion system which includes a differential amplifier circuit which amplifies a received signal, a mixer which combines the amplified received signal and an oscillation signal having a predetermined frequency to perform frequency conversion, and a high gain amplifier circuit in which programmable gain amplifiers and filters which eliminate noise of the received signal, are connected in a multistage and which is configured such that an amplification factor is varied according to the level of the received signal. In the receiving circuit, the low noise amplifier is brought to a non-operating state to allow execution of a DC offset cancel operation of the programmable gain amplifier on the pre-stage side of the high gain amplifier circuit. Thereafter, the low noise amplifier is brought to an operating state to allow execution of a DC offset cancel operation of the final-stage programmable gain amplifier.

A controller that is linearly responsive to an input voltage provides continuously adjustable control of the width of a periodically repeating digital pulse, thereby achieving a linear voltage to duty-cycle ratio transfer function. The circuit of the present invention includes a master clock input, a ratio control voltage input, a controlled duty cycle clock output, a high gain amplifier configured as an integrator having differential inputs, each equipped with a low pass filter, a controlled current source, a resettable timing capacitor, a threshold detector and a reference pulse generator.

A receiving circuit of a direct conversion system is provided which includes a differential amplifier circuit which amplifies a received signal, a mixer which combines the amplified received signal and an oscillation signal having a predetermined frequency to thereby perform frequency conversion, and a high gain amplifier circuit in which a plurality of programmable gain amplifiers and a plurality of filters which eliminate noise of the received signal and an unnecessary wave, are connected in a multistage and which is configured such that an amplification factor is varied according to the level of the received signal. In the receiving circuit, the low noise amplifier is brought to a non-operating state to thereby allow execution of a DC offset cancel operation of the corresponding programmable gain amplifier on the pre-stage side of the high gain amplifier circuit. Thereafter, the low noise amplifier is brought to an operating state to thereby allow execution of a DC offset cancel operation of the final-stage programmable gain amplifier.

The present invention utilizes multiple A / D (analog-to-digital) paths and cross-path calibration to provide accurate and reliable measurements for each input channel in a data acquisition system. When the system and method are applied, user and automated methods of selecting among a number of alternative input range settings can be reduced, or even eliminated. That is, there is a significant reduction or complete elimination of input range settings in a measurement system. For each measurement channel of interest, the input signal is directed to at least two paths, e.g., Path A and Path B. The first path measures the full range (e.g., + / −10 volts), while the second path includes a high-gain amplifier. Each path includes an analog-to-digital converter (ADC), so that there is a one-to-one correspondence between the number of paths and the number of ADCs, which sample the input signal simultaneously.

A traveling wave device employs an active Gallium Nitride FET. The Gallium Nitride FET has a plurality of gate feeding fingers connecting to an input gate transmission line. The FET has a drain electrode connected to an output drain transmission line with the source electrode connected to a point of reference potential. The input and output transmission lines are terminated with terminating impedances which are not matched to the gate and drain transmission lines. The use of Gallium Nitride enables the terminating impedance to be at much higher levels than in the prior art. The use of Gallium Nitride permits multiple devices to be employed, thus resulting in higher gain amplifiers with higher voltage operation and higher frequency operation. A cascode traveling wave amplifier employing GaN FETs is also described having high gain and bandwidth.

A high gain optical amplifier and method. Generally, the inventive amplifier includes a first crystal having an axis and a first index of refraction and a second crystal bonded to the first crystal about the axis and having a second index of refraction. The first index is higher than the second index such that light through the first crystal is totally internally reflected. In the illustrative embodiment, the first crystal is Yb:YAG with an index of approximately 1.82, the second crystal is Sapphire with an index of approximately 1.78, and the axis is the propagation axis. The invention is, in its preferred embodiment, a light guide fabricated out of crystalline materials, diffusion bonded together. If the core of the light guide is doped with laser ions, high gain amplifiers made be designed and operable over a large étendue. With a judicious choice of the laser crystal and cladding materials, shape, and bonding technique, the guided amplifier is much less susceptible to parasitic oscillation than amplifiers constructed in accordance with conventional teachings. The clad core is also able to handle larger thermal load without breakage than can an unclad core.

An RF transmitter with improved efficiency and good linearity decomposes an input AM signal into two signal envelopes with phased modulation at a phase angle θ. The transmitter has three principal embodiments. A first solution uses at least one added RF amplifier for each decomposed signal envelope with one or more amplifiers having a low gain compared to that of a high gain amplifier in another branch for the same signal envelope. A phase angle θi is determined that corresponds to a switching on two of the 2n+2 total branches, n=0, 1, 2, . . . . A second solution uses the same general schematic architecture as the classic LINC system that requires only two RF amplifiers, but uses a different decomposition because the two RF amplifiers are used in their nonlinear zone. The decomposed signal envelopes can be variable. The amplified output signal allows the combiner to be used at 100% efficiency in major part of signal. The third solution combines the first and second solutions.