A memory device including a plurality of memory units; at least one geometric mean operator coupled to at least two of the plurality of memory units; and a memory state reader coupled to the at least one geometric mean operator to read a memory state of the plurality of memory units.

A radio frequency (RF) filter circuit for rejecting one or more spurious components of an input signal has a first resonator circuit including a first capacitor and a first coupled inductor pair of a first inductor and a second inductor, and a second resonator circuit with a second capacitor and a second coupled inductor pair of a third inductor and a fourth inductor. First and second resonator coupling capacitors are connected to the first resonator circuit and the second resonator circuit. A first port and a second port are connected to the first resonator circuit and the second resonator, with the filtered signal of the input signal passed through both the first resonator circuit and the second resonator circuit being output.

A filter includes: a series part disposed between a signal input terminal and a signal output terminal, and including at least one first bulk-acoustic resonator; an inductor portion including a first inductor disposed between ends of the series part and a second inductor having a first end connected to a connection node of the series part and the first inductor; and a shunt part disposed between a second end of the second inductor and a ground, and including at least one second bulk-acoustic resonator, wherein a resonant frequency of the at least one second bulk-acoustic resonator is higher than a resonant frequency of the at least one first bulk-acoustic resonator.

A Bulk Acoustic Wave (BAW) resonator filter can include a BAW resonator pass-band filter ladder, where the BAW resonator pass-band filter ladder can be configured to pass frequency components of an input signal in a pass-band of frequencies received at an input node of the BAW resonator pass-band filter ladder to an output node of the BAW resonator pass-band filter ladder. A first rejection-band series resonator can be coupled in series between an input port of the BAW resonator pass-band filter ladder and the input node, where the first rejection-band series resonator can have a first anti-resonant frequency peak in a rejection-band of frequencies that is less than the pass-band of frequencies. A second rejection-band series resonator can be coupled in series between an output port of the BAW resonator filter and the output node, where the second rejection-band series resonator can have a second anti-resonant frequency peak in the rejection-band of frequencies.

A multiplexer includes: a first terminal; a second terminal; a third terminal; a first filter connected between the first and second terminals, including a first capacitor, a first inductor, and one or more first acoustic wave resonators, and having a first passband; a second filter connected between the first and third terminals, including a second capacitor, a second inductor, and one or more second acoustic wave resonators, and having a second passband higher than the first passband; a substrate having a surface on which at least one first acoustic wave resonator of the one or more first acoustic wave resonators and at least one second acoustic wave resonator of the one or more second acoustic wave resonators are located; and a metal structure located on the surface and located between the at least one first acoustic wave resonator and the at least one second acoustic wave resonator.

In tuning a radio frequency (RF) module including a non-volatile tunable RF filter, a desired frequency and an undesired frequency being provided by an amplifier of the RF module are detected. The non-volatile tunable RF filter is coupled to an output of the amplifier of the RF module. A factory setting of an adjustable capacitor in the non-volatile tunable RF filter is changed by factory-setting a state of a non-volatile RF switch, such that the non-volatile tunable RF filter substantially rejects the undesired frequency and substantially passes the desired frequency. The adjustable capacitor includes the non-volatile RF switch, and the factory setting of the adjustable capacitor corresponds to a factory-set state of the non-volatile RF switch. An end-user is prevented access to the non-volatile RF switch, so as prevent the end-user from modifying the factory-set state of the non-volatile RF switch.

A directional coupler includes a main line through which a first signal in a first frequency band and a second signal in a second frequency band pass from a first port to a second port, a sub-line electromagnetically coupled to the main line and having a third port and a fourth port, the third port outputting a first coupled signal corresponding to the first signal and a second coupled signal corresponding to the second signal, a first termination circuit connected to the fourth port and used in outputting the first coupled signal, a second termination circuit connected to the fourth port and used in outputting the second coupled signal, and a first filter circuit disposed between the fourth port and the first termination circuit, wherein the first filter circuit has frequency characteristics allowing the first coupled signal to pass therethrough and attenuating the second coupled signal.

A filter having a pass band includes a series circuit in which a series arm resonator and a first inductor are connected in series with each other and which forms at least part of a signal path R connecting a first input/output terminal and a second input/output terminal and a parallel arm resonator connected between one end of the series circuit and a ground. The series circuit becomes inductive in the pass band. An anti-resonant frequency of the series arm resonator is higher than a frequency at a higher-frequency end of the pass band. A resonant frequency of the parallel arm resonator is higher than the anti-resonant frequency of the series arm resonator.

Motion-detection systems are often used to detect presence of humans. Such motion-detection systems are often based on passive infrared (PIR) sensors. Unfortunately, such detection systems are unable to reliably distinguish between humans and other entities such as animals and moving heat sources. To address this issue, it is proposed to detect a presence of real time clock (RTC) devices in addition to detecting the heat sources to better determine whether a detected entity is a human.

An analog to digital conversion circuit includes an analog to digital converter (ADC) circuit operable to convert an analog signal having an oscillation frequency into a first digital signal having a first data rate frequency, where the analog signal includes a set of pure tone components. The analog to digital conversion circuit further includes a digital decimation filtering circuit operable to convert the first digital signal into a second digital signal having a second data rate frequency. The analog to digital conversion circuit further includes a digital bandpass filter (BPF) circuit operable to convert the second digital signal into an outbound digital signal having a third data rate frequency, where the digital bandpass filter circuit is set to produce a bandpass region approximately centered at the oscillation frequency of the analog signal and having a bandwidth tuned for filtering a pure tone.