Abstract: A low-loss high-voltage multiplexer is implemented using a transformer that is connected to one transmitter, one receiver and transducer elements. At least one primary winding is magnetically coupled at least two secondary windings. For example, a first transducer element and a second transducer element are connected to the secondary windings of a multiplexer that multiplexes between these transducer elements via the secondary windings. The multiplexer also optionally switches between the transmitter and the receiver during the transmission and the reception.

Abstract: A low-loss high-voltage multiplexer is implemented using a transformer that is connected to one transmitter, one receiver and transducer elements. At least one primary winding is magnetically coupled at least two secondary windings. For example, a first transducer element and a second transducer element are connected to the secondary windings of a multiplexer that multiplexes between these transducer elements via the secondary windings. The multiplexer also optionally switches between the transmitter and the receiver during the transmission and the reception.

Abstract: The subarrays are formed dynamically switching the individual output signals from the transducer elements on an element-to-element basis after the time delay circuits have individually perform on the signal signals for time delay. For example, at least one crosspoint switch flexibly connects the time-delayed outputs on the element-to-element basis in order to dynamically form predetermined sets of subarrays. The subarrays are optionally unequal in shape and or a number of transducer elements.

Abstract: An amplifier has a voltage to current converter coupled between a first potential and a reference potential and includes a control input coupled to a voltage at an input of the amplifier for converting the voltage at the amplifier input into a corresponding output current. A current multiplier is fed by the output current for producing an increased current. The increased current is fed to a control electrode of a transistor. A feedback element provides the first potential to the voltage to current converter by coupling a voltage produced by the feedback element in response current through the transistor to the voltage to current converter.

Abstract: A system for producing a control signal to a plurality of amplifiers sections to vary the gain of each one of the plurality of amplifier sections as a linear natural logarithmic function of an input gain control signal. The system includes a master circuit for producing a pair of currents with a ratio proportional to the linear natural logarithmic function of the input gain signal and a differential voltage. Each one of the amplifier sections includes: a replica of a portion of the master circuit fed by the produced differential voltage for producing a pair of currents produced in the master circuit; and an amplifier fed by the produced replicated currents, such amplifier having a gain proportional to the ratio of such replicated currents.

Abstract: Ultrasound information for B-mode and CW Doppler mode use the same digital beamformer. Due to sigma-delta conversion or over sampling, sufficient dynamic range is provided for the desired bandwidth. By mixing the input ultrasound information to base band before conversion, additional dynamic range may be provided. The electrical impedance may be better matched to elements by connecting a different number of sigma-delta converters to an element. Elements with lower impedance may be connected to a plurality of sigma-delta converters. To increase the aperture size for elements with a higher impedance, the same sigma-delta converters may be used as separate receive beamformer channels without the summation.

Abstract: Receive beamformers for receive beamforming ultrasound information include a plurality of channels. The received signals for each channel are oversampled for conversion to digital form, such as sampling with a sigma-delta converter. The reconstruction of the samples into data at the Nyquist or other rate is performed in stages. Partial reconstruction to a rate less than the oversampling rate, but greater than the Nyquist rate, occurs prior to summation across channels. Delays are implemented by selecting data from the sample stream. After summation, the samples are reconstructed at a Nyquist or other rate.

Abstract: A system for producing a control signal to a plurality of amplifiers sections to vary the gain of each one of the plurality of amplifier sections as a linear natural logarithmic function of an input gain control signal. The system includes a master circuit for producing a pair of currents with a ratio proportional to the linear natural logarithmic function of the input gain signal and a differential voltage. Each one of the amplifier sections includes: a replica of a portion of the master circuit fed by the produced differential voltage for producing a pair of currents produced in the master circuit; and an amplifier fed by the produced replicated currents, such amplifier having a gain proportional to the ratio of such replicated currents.

Abstract: An amplifier has a voltage to current converter coupled between a first potential and a reference potential and includes a control input coupled to a voltage at an input of the amplifier for converting the voltage at the amplifier input into a corresponding output current. A current multiplier is fed by the output current for producing an increased current. The increased current is fed to a control electrode of a transistor. A feedback element provides the first potential to the voltage to current converter by coupling a voltage produced by the feedback element in response current through the transistor to the voltage to current converter.

Abstract: A voltage controlled oscillator (VCO) for use in a personal area network synthesizer includes a delay cell (100), a first current amplifier (201, 203) for amplifying an input current, a resister capacitor (RC) tuning network (207, 209, 211) for varying the amount of amplification and delay of an output of the first current amplifier. A second current amplifier (213, 215) is then used for amplifying an output current from the RC tuning network. The invention includes a unique composite voltage variable capacitor (CVVC) (300) for precisely tuning the amount of delay presented by the delay cell. The unique topology of the delay cell (100) allows it to be readily used in voltage controlled oscillators (VCOs) operable at frequencies above 1 GHz.