Abstract: Methods and devices to reduce the gate-induced drain/body leakage current (GIDL) generated in FET switch stacks when in OFF state are disclosed. Such devices include inductors as part of bias networks coupled with drain/source terminals and/or body terminals of the transistors within the switch stack. Hybrid approaches where resistors in combination with inductors are implemented as part the bias network are also described.

Abstract: A clamping circuit that may be used to provide efficient and effective voltage clamping in an RF front end. The clamping circuit comprises two series coupled signal path switches and a bypass switch coupled in parallel with the series coupled signal path switches. A diode is coupled from a point between the series coupled signal path switches to a reference potential. In addition, an output selection switch within an RF front end has integrated voltage clamping to more effectively clamp the output voltage from the RF front end. Additional output clamping circuits can be used at various places along a direct gain signal path, along an attenuated gain path and along a bypass path.

Abstract: Methods and devices to improve the switching speed of radio frequency FET switch stacks are disclosed. The described methods and devices are based on bypassing drain-sources resistors when the FET switch stack is transitioning from an ON to an OFF state. Several implementations of the disclosed teachings are also presented.

Abstract: Methods and devices to reduce the gate-induced drain/body leakage current (GIDL) generated in FET switch stacks when in OFF state are disclosed. Such devices include inductors as part of bias networks coupled with drain/source terminals and/or body terminals of the transistors within the switch stack. Hybrid approaches where resistors in combination with inductors are implemented as part the bias network are also described.

Abstract: Methods and devices to improve the switching speed of radio frequency FET switch stacks are disclosed. The described methods and devices are based on bypassing drain-sources resistors when the FET switch stack is transitioning from an ON to an OFF state. Several implementations of the disclosed teachings are also presented.

Abstract: Methods and systems for frequency band allocation are provided. A tunable/selectable passband filter is disclosed that changes based on the time and location of the user equipment. Additionally, a method of allocating and optimizing upload and download bands is provided to mitigate inter-modulation distortion due to intermodular distortion effects from strong uplink channels.

Abstract: A phase shifter unit cell or a connected set of such cells that can be well isolated from external circuitry and which do not introduce insertion loss into an RF signal path, exhibit good return loss, and further provides additional advantages when combined with bracketing attenuator circuits. More particularly, embodiments integrate a high-isolation function within a phase shifter circuit by breaking the complimentary nature of the control signals to a phase shifter cell to provide greater control of switch states internal to the phase shifter cell and thus enable a distinct high-isolation state, and by including a switchable shunt termination resistor for use in the high-isolation state. Some embodiments are serially coupled to attenuator circuits to enable synergistic interaction that reduces overall die size and/or increases isolation. One such embodiment positions a high-isolation phase shifter cell in accordance with the present invention between bracketing programmable attenuators.

Abstract: A clamping circuit that may be used to provide efficient and effective voltage clamping in an RF front end. The clamping circuit comprises two series coupled signal path switches and a bypass switch coupled in parallel with the series coupled signal path switches. A diode is coupled from a point between the series coupled signal path switches to a reference potential. In addition, an output selection switch within an RF front end has integrated voltage clamping to more effectively clamp the output voltage from the RF front end. Additional output clamping circuits can be used at various places along a direct gain signal path, along an attenuated gain path and along a bypass path.

Abstract: Digital step attenuator (DSA) and digital phase shifter (DPS) multi-stage circuit architectures that provide for high resolution. Embodiments use a dithering approach to weight bit positions to provide a much finer resolution than the lowest-valued individual stage. Bit position weights for stages are determined so as to enable selection of combinations of n bit positions that provide a desired total attenuation or phase shift range while allowing utilization of the large number of states (2n) available to produce fractional intermediate steps of attenuation or phase shift. The fractional intermediate steps have a resolution finer than the lowest-valued stage. Bit position weights may be determined using a weighting function, including weightings determined from a linear series, a geometric series, a harmonic series, or alternating variants of such series. In some embodiments, at least one bit position has a fixed value that is not determined by the bit position weighting function.

Abstract: A method of determining the status of a lock. The method includes reading data from a proximity switch and calculating an inductance value from a solenoid, the proximity switch and solenoid located in or around a lock, and processing the data from the proximity switch and the inductance value. The method further includes comparing the processed data with an expected value to confirm the lock status.

Abstract: Circuits and methods that enable stable and reliable “hot switching” from one antenna to another without turning RF power to the antennas OFF in wireless RF systems during at least some transmission events. One embodiment comprises an RF switch circuit including a common port configured to pass an RF signal, a plurality of switch arms each coupled to the common port and including an associated port, and a shunt termination impedance selectively couplable to the common port through a switch. Another embodiment comprises a method for switching an RF signal applied to a common port of a switch from a first switch arm initially in an ON state to a second switch arm initially in an OFF state, including: setting the second switch arm to the ON state, and then setting the first switch arm to the OFF state.

Abstract: A clamping circuit that may be used to provide efficient and effective voltage clamping in an RF front end. The clamping circuit comprises two series coupled signal path switches and a bypass switch coupled in parallel with the series coupled signal path switches. A diode is coupled from a point between the series coupled signal path switches to a reference potential. In addition, an output selection switch within an RF front end has integrated voltage clamping to more effectively clamp the output voltage from the RF front end. Additional output clamping circuits can be used at various places along a direct gain signal path, along an attenuated gain path and along a bypass path.

Abstract: Circuits and methods that provide fine-resolution measurements of RF signal power within a communication system band, thereby more accurately measuring RF interference or the potential of RF interference. One aspect of embodiments of the present invention is a narrow-band tunable filter that includes two elements coupled in series, a periodic passband filter and a tunable filter. The purpose of the periodic passband filter is to generate multiple periodic passbands for an applied RF signal. The purpose of the tunable filter is to generate a single passband, generally with a tunable center frequency. By serially coupling the two filter types in either order, the single passband of the tunable filter is superimposed over one of the periodic passbands of the periodic passband filter, synergistically resulting in an extremely narrow passband.

Abstract: Digital step attenuator (DSA) and digital phase shifter (DPS) multi-stage circuit architectures that provide for high resolution. Embodiments use a dithering approach to weight bit positions to provide a much finer resolution than the lowest-valued individual stage. Bit position weights for stages are determined so as to enable selection of combinations of n bit positions that provide a desired total attenuation or phase shift range while allowing utilization of the large number of states (2n) available to produce fractional intermediate steps of attenuation or phase shift. The fractional intermediate steps have a resolution finer than the lowest-valued stage. Bit position weights may be determined using a weighting function, including weightings determined from a linear series, a geometric series, a harmonic series, or alternating variants of such series. In some embodiments, at least one bit position has a fixed value that is not determined by the bit position weighting function.

Abstract: A programmable voltage variable attenuator (VVA) that enables selection among multiple analog, continuous attenuation ranges. Some embodiments include a dual-mode interface to enable digitally programming a DAC and provide the analog output to control the attenuation level of the VVA, or alternatively apply an externally provided analog voltage to directly control the VVA attenuation level. A VVA may be used in conjunction with a digital step attenuator (DSA). Some embodiments include circuitry for changing the VVA reference impedance. The attenuator architecture of the VVA includes one or more variable resistance shunt elements and/or series elements which may be a resistor and FET circuit controlled by a provided variable analog voltage. The multiple resistance element architecture may be implemented with stacked FET devices. Embodiments for the VVA may be based, for example, on T-type, Bridged-T type, Pi-type, L-pad type, reflection type, or balanced coupler type attenuators.

Abstract: An apparatus for detecting difference in operating characteristics of a main circuit by using a replica circuit is presented. In one exemplary case, a sensed difference in operating characteristics of the two circuits is used to drive a tuning control loop to minimize the sensed difference. In another exemplary case, several replica circuits of the main circuit are used, where each is isolated from one or more operating variables that affect the operating characteristic of the main circuit. Each replica circuit can be used for sensing a different operating characteristic, or, two replica circuits can be combined to sense a same operating characteristic.

Abstract: Methods and devices to improve the switching speed of radio frequency FET switch stacks are disclosed. The described methods and devices are based on bypassing drain-sources resistors when the FET switch stack is transitioning from an ON to an OFF state. Several implementations of the disclosed teachings are also presented.

Abstract: Methods and systems for determining the error vector magnitudes for an RF device by fitting voltage magnitudes to a Rayleigh distribution to produce weighting parameters for an EVM calculation, either in simulation for designing the RF device or as validation measurements from a physical RF device.

Abstract: Methods and apparatuses for providing a reduction in output power of a balanced amplifier configuration are presented. According to one aspect, reduction of the output power is provided by deactivating one of the two amplification paths of the balanced amplifier. According to another aspect, impedances seen at ports of input and output couplers of the balanced amplifier configuration part of a deactivated amplification path are selectively switched in dependence of operation according to the reduced output power or according to normal output power. In addition, or in the alternative, impedance seen at an isolated/terminated port of the input and/or the output coupler is selectively switched in dependence of the operation. When operating according to the reduced output power, values of the switched impedances can be adjusted to tune a frequency response of the balanced amplifier.

Abstract: Methods and devices to improve the switching speed of radio frequency FET switch stacks are disclosed. The described methods and devices are based on bypassing drain-sources resistors when the FET switch stack is transitioning from an ON to an OFF state. Several implementations of the disclosed teachings are also presented.