摘要:
In an embodiment, a digital pre-distortion apparatus processes an input signal to produce a pre-distorted signal, and processes the pre-distorted signal to produce a feedback signal. The apparatus also rotates an adjustment gain by a gain rotation angle to produce a rotated adjustment gain, where the gain rotation angle is based on a phase difference between the input signal and the feedback signal. The apparatus also applies the rotated adjustment gain to the feedback signal, which may result in rotation of the feedback signal into a target phase region.
摘要:
A radio frequency (“RF”) power amplifier circuit as described herein is configured to detect and measure an output load mismatch and to adjust the operating characteristics of the RF power amplifier to reduce output signal distortion. The circuit includes a directional RF signal coupler that obtains a coupled reflected RF signal that is indicative of the output load mismatch. The coupled reflected RF signal is processed to generate one or more bias control signals for the RF power amplifier. In operation, a mismatch condition will result in a measurable coupled reflected RF signal and a corresponding reduction in output power from the RF power amplifier. Ultimately, the output power control mechanism strives to maintain the RF power amplifier within a linear operating range.
摘要:
An ethylene polymer having a Polydispersity Index of at least about 3.0, a melt index, MI, and a Relaxation Spectrum Index, RSI, such that (RSI)(MI.sup..alpha.) is greater than about 26 when .alpha. is about 0.7, and a Crystallizable Chain Length Distribution Index, L.sub.w /L.sub.n, less than about 3 is provided. Such ethylene polymer has processability equivalent or superior to even conventional high pressure polyethylene at similar melt index, yet need not be made under high pressure reaction conditions.
摘要:
A process comprising:(a) introducing a mixture comprising one or more alpha-olefins, carbon monoxide, and, optionally, one or more dienes into a reaction zone under polymerization conditions;(b) contacting the mixture with a catalyst prepared by a process comprising:(i) providing a transition metal in the zero valence state adsorbed on a support;(ii) reacting the supported metal with an oxidant to form a supported compound wherein the metal has a positive valence;(iii) ligating the supported compound with a ligand; and(c) introducing a reoxidant into the reaction zone to maintain the positive valence of the metal.
摘要:
A wireless communication unit comprises a transmitter having a forward path comprising a power amplifier, PA, and a feedback path arranged to feed back a portion of a signal output from the PA to a point in the forward path prior to the PA. The forward path and feedback path form a constant gain tracking (CGT) loop. The feedback path comprises an adaptive predistortion logic module located outside of the CGT loop and arranged to form an APD loop with the forward path and feedback path. The CGT loop comprises a controller logic module arranged to determine a gain offset of a signal routed through the forward path and feedback path and in response thereto set a drive level of the PA.
摘要:
A wireless communication unit comprising a transmitter having a power amplifier, a controller logic module arranged to control a power control value of the power amplifier and a closed loop control system operably coupled to the power amplifier and arranged to monitor a level of peak PA compression, wherein in response to the identified level of peak PA compression the controller logic module is arranged to automatically adjust a power amplifier power control value of the PA to obtain a predetermined level of peak PA compression.
摘要:
A soft saturation detection circuit for a radio frequency (“RF”) power amplifier is configured to detect the onset of soft saturation in an unambiguous and accurate manner. The circuit compares the time derivative of a voltage signal indicative of the RF output power to the time derivative of a control voltage signal for the RF power amplifier. The circuit also employs a gating mechanism that ensures that a soft saturation indication signal is generated under appropriate operating conditions.
摘要:
An ethylene polymer havinga) a Polydispersity Index, PDI, of about 3 to 9;b) an nRSI of about 5 to about 18;c) a cRSI of about 1.1 to 3.0;d) a Composition Distribution Index, CDI(100), greater than about 45; ande) a log-viscosity ratio, log(.eta.0/[.eta.]), of about 0.5 to about 1.5 is described. The ethylene polymer has improved processability over conventional linear low density polyethylene.
摘要:
A wireless communication unit comprises a transmitter having a forward path comprising a power amplifier, PA, and a feedback path arranged to feed back a portion of a signal output from the PA to a point in the forward path prior to the PA. The forward path and feedback path form a constant gain tracking (CGT) loop. The feedback path comprises an adaptive predistortion logic module located outside of the CGT loop and arranged to form an APD loop with the forward path and feedback path. The CGT loop comprises a controller logic module arranged to determine a gain offset of a signal routed through the forward path and feedback path and in response thereto set a drive level of the PA.
摘要:
A polymer of the invention comprising the comonomers ethylene, one or more alpha-olefins having 3 to 20 carbon atoms, and one or more cyclic dienes having up to 30 carbon atoms, said polymer having a density of at least 0.890 gram per cubic centimeter; long chain branching; a plurality of double bonds; an Mw/Mn ratio ratio (PDI) of at least 2.5; a flow activation energy of greater than about 6.5 kcal/mol; and a Relaxation Spectrum Index (RSI), PDI, and Melt Index (MI), such that RSI·MIa>2.7 and RSI·MIa·PDIb is in the range of about 0.8 to about 60, when a and b are about 0.6 and minus 1.2, respectively.