Abstract: This invention describes the obtainment of impact-resistant materials from a block copolymer that comprises as monomers an alkadiene (conjugated diene) and a vinyl aromatic compound, which is used as impact modifier to obtain such materials and in which, at least, one of the blocks of the vinyl aromatic compound is polydisperse. The invention allows obtaining morphologies such as rods, points or capsules by incorporating such copolymer into a polymeric matrix derived from vinyl aromatic monomers independently from other agents such as chain transfer agents, and achieving increases, in the impact values up to 50% through the use of the copolymer of this invention.

Abstract: Receiver embodiments are disclosed that can process a wide range of transmission bandwidths over a wide range of transmission frequencies and provide reduced converter sampling rates, filter bandwidths, and filter tuning ranges and enhanced signal-to-noise performance.

Abstract: A radio transmission power control circuit includes a radio frequency (rf) downconverter that produces a downconverter output representative of the difference between a first downconverter input based on a transmitted signal of a radio transmitter and a second downconverter input based on a local oscillator signal. A receiver baseband circuit processes the downconverter output to produce an analog power signal representative of the transmitted signal. A digital to analog converter converts the analog power signal to a representative digital power signal. A feedback control circuit produces a transmitter gain control signal to control transmitted signal power so as to minimize the difference between the digital power signal and a power reference signal.

Abstract: A signal having a substantially uniform spectral distribution, e.g., a flat noise signal such as a signal ground, is provided at the input of a bandpass filter such as an IF filter of a receiver circuit, to thereby produce an output signal at the output of the bandpass filter. The output signal is processed in a limiter to produce a limited signal. An average frequency of the limited signal is determined, and the bandpass filter is adjusted based on the determined average frequency. According to one embodiment of the present invention, the bandpass filter comprises a Gm-C filter having a transconductance, and the filter is adjusted by adjusting the transconductance of the Gm-C filter based on the determined average frequency. According to another aspect of the present invention, a desired center frequency for the bandpass filter is identified. A resolution and a desired confidence interval are also identified.

Abstract: A transceiver of a dual-band radio is provided that selectively transmits and receives on either of a first frequency and a second frequency wherein the transceiver includes an integrated circuit having a power amplifier configured to amplify signals for transmission on a first frequency, and a low-noise amplifier configured to amplify signals received on the second frequency. The transceiver may further include a second integrated circuit having a power amplifier configured to amplify signals for transmission on a second frequency, and a low-noise amplifier configured to amplify signals received on the first frequency.

Abstract: Differential amplifiers include biasing circuits therein that can automatically account for process and/or temperature induced variations in &bgr; and thereby more uniformly maintain the voltage gain of the differential amplifier at a desired level. A differential amplifier is provided that comprises first and second bipolar transistors electrically coupled together as an emitter-coupled pair (ECP) and a biasing circuit that is electrically connected to first and second emitters of the first and second bipolar transistors, respectively. This biasing circuit includes a current mirror that sets a magnitude of an emitter bias current in the first emitter at a value proportional to (&bgr;+Z+1)/(&bgr;+1), where &bgr; is the gain of the first bipolar transistor and 1≦Z≦2. In this manner, the gain of the differential amplifier can be set at a level proportional to (&bgr;2+2&bgr;)/(&bgr;2+2&bgr;+1) which is a relatively weak function of &bgr;, even for small &bgr;.

Abstract: A signal having a substantially uniform spectral distribution, e.g., a flat noise signal such as a signal ground, is provided at the input of a bandpass filter such as an IF filter of a receiver circuit, to thereby produce an output signal at the output of the bandpass filter. The output signal is processed in a limiter to produce a limited signal. An average frequency of the limited signal is determined, and the bandpass filter is adjusted based on the determined average frequency. According to one embodiment of the present invention, the bandpass filter comprises a Gm-C filter having a transconductance, and the filter is adjusted by adjusting the transconductance of the Gm-C filter based on the determined average frequency. According to another aspect of the present invention, a desired center frequency for the bandpass filter is identified. A resolution and a desired confidence interval are also identified.

Abstract: A signal having a substantially uniform spectral distribution, e.g., a flat noise signal such as a signal ground, is provided at the input of a bandpass filter such as an IF filter of a receiver circuit, to thereby produce an output signal at the output of the bandpass filter. The output signal is processed in a limiter to produce a limited signal. An average frequency of the limited signal is determined, and the bandpass filter is adjusted based on the determined average frequency. According to one embodiment of the present invention, the bandpass filter comprises a Gm-C filter having a transconductance, and the filter is adjusted by adjusting the transconductance of the Gm-C filter based on the determined average frequency. According to another aspect of the present invention, a desired center frequency for the bandpass filter is identified. A resolution and a desired confidence interval are also identified.

Abstract: A differential amplifier having reduced even-order non-linearity is provided that comprises a differential amplifier and an analog voltage compensation circuit that is coupled to one of the input ports to the differential amplifier so as to provide an analog compensation voltage to that input port so as to reduce the imbalance in the differential amplifier. In a preferred embodiment of the present invention, the analog voltage compensation circuit comprises a transconductance amplifier that is coupled between the output of the differential amplifier and one of the inputs of the differential amplifier which may be used to sense the effect of the imbalance on the output of the differential amplifier, and a direct current voltage source coupled to each of the inputs to the differential amplifier.

Abstract: An improved receiver architecture utilizing active filters for frequency conversion, wherein the final IF stage operates at a frequency higher than the previous IF stage, is disclosed to facilitate the processing by a baseband system operating at higher IF of signals from receivers operating at lower IFs and to enable the continued use of existing post-IF devices with multiple-conversion receivers. A low IF signal output is digitally mixed with a divided local oscillator signal to achieve a higher IF which is suited for processing by post-IF components such as a detector. The mixed signal is then filtered by a low dynamic range active filter and limited.

Abstract: A high dynamic range receiver IF system using limited dynamic range IF filters is disclosed. A variable gain amplifier amplifies a first IF signal. The amplified first IF signal is then applied to an image suppression mixer for suppressing an image component of the amplified first IF signal to provide adequate image suppression for a radio system, wherein the image suppression mixer outputting an image suppressed second IF signal. An active bandpass filter then filters the unwanted components from the second IF signal. The filtered signal is then hard limited in a limiting amplifier which outputs a limited IF signal. A logarithmic detector then provides a received signal strength indicator.

Abstract: A power-on reset circuit for generating and maintaining a reset signal in an active low state during power-up until a power supply voltage exceeds a predetermined level includes a resetting circuit (12a) and a control logic circuit (12b). The reset circuit is responsive to a monitoring signal, a start-up signal and a reference voltage for generating a reset signal which is initially in the active low state. The reset circuit includes a differential comparator (54) having a first input for receiving the start-up signal, a second input for receiving the reference voltage, and an output for generating the reset signal. The control logic circuit is responsive to the monitoring signal and the reset signal for generating a logic control signal which is initially in a high state. The differential comparator is responsive to the control signal and is activated only after the power supply voltage has exceeded a predetermined level so as to maintain initially the reset signal on its output in the low state.

Abstract: A positive power supply for generating and supplying a regulated positive potential to control gates of selected memory cells via word lines in an array of flash EEPROM memory cells during programming includes a clock circuit (18b) for generating a pair of non-overlapping clock signals and charge pump means (18c) responsive to an external power supply potential (VCC) and to the non-overlapping clock signals for generating a high positive voltage. A regulator circuit (20) responsive to the high positive voltage and a reference voltage is provided for controlling the regulated positive potential so that it is independent of the external power supply potential (VCC).

Abstract: A negative power supply for generating and supplying a regulated negative potential to control gates of selected memory cells via wordlines in an array of flash EEPROM memory cells during flash erasure includes charge pumping means (12) formed of a plurality of charge pump stages (401-404) for generating a high negative voltage, and cancellation means coupled to each stage of the charge pump means for effectively canceling out threshold voltage drops in the charge pump means. A regulator means (16) responsive to the high negative voltage and a reference potential is provided for generating the regulated negative potential so that it is independent of an external supply potential (VCC).

Abstract: A drain power supply for generating and supplying a regulated positive potential to drain regions of selected memory cells via bit lines in an array of flash EEPROM memory cells during programming includes charge pump means (20) formed of a plurality of charge pump sections (20a-20h) driven by one of a plurality of staggered clock signals for generating a moderately high level positive voltage. Cancellation means (26, 28) are coupled to each of the plurality of charge pump sections for effectively canceling out threshold voltage drops in the charge pump circuit. A regulator circuit (22) responsive to the regulated positive potential at an output node and a reference voltage is provided for generating a control voltage so as to control the high level positive voltage on the output node.