Abstract:
A pen voltage regulator is provided for supplying a regulated pen voltage to one or more printheads of an inkjet printer. The pen voltage regulator includes: a regulator switch arranged between an input terminal and an output terminal; a linear lifting circuit connected to the regulator switch; a soft start circuit arranged between the regulator switch and the output terminal; an output filter arranged between the soft start circuit and the output terminal; and a pulse width modulation (PWM) controller connected to the linear filtering circuit. The PWM controller is arranged to provide a pulse width modulated control signal to the linear filtering circuit. The linear filtering circuit is configured to transmit a smoothed control signal to the regulator switch and to ensure that the regulator switch is operable in a linear region. The soft start circuit is configured to provide a soft-start mode of operation so as to prevent the generation of large inrush currents and to provide overload protection.
Abstract:
The present invention relates to methods for improving the transformation frequency of Agrobacterium-mediated transformation of maize embryos. A preferred method for transforming maize using Agrobacterium comprises the steps of: contacting at least one immature embryo from a maize plant with Agrobacterium capable of transferring at least one gene to said embryo; co-cultivating the embryos with Agrobacterium; culturing the embryos in medium comprising N6 salts, an antibiotic capable of inhibiting the growth of Agrobacterium, and a selective agent to select for embryos expressing the gene; and regenerating plants expressing the gene.
Abstract:
The invention provides a thermal structure coupling analysis method of a solid rocket motor nozzle considering the structural gaps, comprising S1: establish a model of flow field in nozzle and ascertain the cross-sectional area at different positions along the axis, perform quasi-one-dimensional isentropic flow analysis of the nozzle flow field by Newton iteration method; S2: use Bartz formula to ascertain the boundary of the nozzle convective heat transfer coefficient; S3: establish a numerical analysis project of nozzle thermal structure; a two-dimensional axisymmetric model of the nozzle thermal protection structure and a material model thereof; S4: proceed a numerical analysis of the nozzle thermal protection structure heat transfer, including model setting, material setting, contact setting, meshing, solution parameter setting, boundary condition setting, solution and result post-processing; S5: proceed a numerical analysis of the nozzle thermal protection structure thermal stress, including solution parameter setting, boundary condition setting, solution and result post-processing.
Abstract:
A method of decoding a plurality of diverse signals for low-density parity-check (LDPC) decoders that takes advantage of signal diversity. The method allows for the combining of soft-decision LDPC encoded non-coherently modulated signals, which is in contrast to existing approaches where hard decision combining is used for non-coherently modulated signals. The method includes the steps of inputting each diversity signal into a unique demodulator, and calculating the LLR of each demodulated signal. When the diverse demodulated signals are combined into a single combined signal, each bit of the combined signal is selected according to the value of either the highest LLR value of each bit across the demodulated signals or according to the sum of the LLR of each bit across the demodulated signals.
Abstract:
A compact integrated power amplifier is described herein. In an exemplary design, an apparatus includes (i) an integrated circuit (IC) die having at least one transistor for a power amplifier and (ii) an IC package having a load inductor for the power amplifier. The IC die is mounted on the IC package with the transistor(s) located over the load inductor. In an exemplary design, the IC die includes a transistor manifold that is placed over the load inductor on the IC package. The transistor(s) are fabricated in the transistor manifold, have a drain connection in the center of the transistor manifold, and have source connections on two sides of the transistor manifold. The IC die and the IC package may include one or more additional power amplifiers. The transistor(s) for each power amplifier may be located over the load inductor for that power amplifier.
Abstract:
Techniques for reducing distortion and improving linearity of amplifiers are described. In an exemplary design, an apparatus includes a driver amplifier, a variable matching circuit, and a power amplifier. The driver amplifier amplifies a first RF signal and provides a second RF signal. The variable matching circuit receives the second RF signal and provides a third RF signal. The power amplifier amplifies the third RF signal and provides a fourth RF signal. The variable matching circuit matches a fixed impedance at the output of the driver amplifier to a variable impedance at the input of the power amplifier in order to improve the linearity of the amplifiers. In an exemplary design, the power amplifier includes a first transistor (e.g., an NMOS transistor) of a first type, and the variable matching circuit includes a second transistor (e.g., a PMOS transistor) of a second type that is different from the first type.
Abstract:
Exemplary embodiments are directed to a transmitter with a power amplifier and a switched output matching circuit implementing a plurality of output paths for a plurality of operating modes is described. The power amplifier receives an input RF signal and provides an amplified RF signal. An output matching network performs impedance transformation from low impedance at the power amplifier output to higher impedance at the matching network output. The plurality of output paths are coupled to the output matching network. Each output path provides a different target output impedance for the power amplifier and routes the amplified RF signal from the power amplifier to an antenna when that output path is selected. Each output path may include a matching network coupled in series with a switch. The matching network provides the target output impedance for the power amplifier when the output path is selected. The switch couples or decouples the output path to/from the power amplifier.