A signal processing circuit that achieves functionality similar to that of a switched capacitor circuit without the necessity a clock. The circuit compensates for finite open loop gain and for offset voltages in the components, allowing the circuit to calculate the result of a problem represented by the circuit essentially immediately upon the presentation of a new input or set of inputs. After the circuit is initialized to remove gain, an input is applied to the circuit, and propagates through the network and affects the state of amplifier outputs; the propagation from the input through capacitors to the ultimate output(s) of the circuit is the analog calculation taking place. The calculation is not mediated by a clock, but rather the calculation corresponds to the circuit's one-time response to the application of the inputs. Using these techniques complex signal processing circuits and even analog neural networks may be constructed.

A device having a capacitive sampling structure that allows for removal of sampling noise can be implemented in a variety of applications. Noise cancellation can be achieved by storing on an auto-zero capacitor a scaled replica of kT/C noise by a mechanism of correlated sampling. In an example embodiment, a set of switches can be arranged such that, in switching, scaled thermal noise, generated in an acquisition phase in which a voltage signal is input to an input capacitor structure, is captured on an output capacitor structure and, in a conversion phase, the captured thermal noise is cancelled or compensated from an output of the output capacitor structure.

A microphone device, a telephone device, and a decoupling circuit are provided. The decoupling circuit includes a first capacitor, a first resistor, and a switch. A first terminal of the first capacitor is coupled to a first terminal of an audio source. A first terminal of the first resistor is coupled to a second terminal of the first capacitor, and a second terminal of the first resistor is coupled to a second terminal of the audio source. A first terminal of the switch is coupled to the second terminal of the first capacitor and the first terminal of the first resistor, and a second terminal of the switch is coupled to the second terminal of the audio source. The first capacitor and the first resistor are configured to absorb noise generated by the switch during switching.

A switched capacitor amplifier circuit includes an operational amplifier, a first capacitor and a second capacitor each having one end connected to a negative input terminal of the operational amplifier, a first switching circuit configured to connect the other end of the first capacitor and a signal source during a first operation, a second switching circuit configured to connect the other end of the second capacitor and the output terminal of the operational amplifier so as to connect the output terminal and the negative input terminal of the operational amplifier through the second capacitor during the second operation, and an impedance converter circuit configured to convert an output impedance of the signal source into a specified impedance, the impedance converter circuit being connected between the first switching circuit and the other end of the first capacitor.

An amplifying apparatus includes a variable gain amplifying circuit configured to operate in a gain mode selected from a plurality of gain modes in response to a first control signal during operation in an amplification mode, a variable attenuation circuit configured to have an attenuation value that is adjusted in response to a second control signal, and a phase compensation value which compensates for a phase distortion in the selected gain mode, and a control circuit configured to control the selecting of the gain mode, the adjusting of the attenuation value and the phase compensation value, based on the first and second control signals.

RF signal amplifiers are provided that include an RF input port, one or more active RF output ports, one or more passive RF output ports, an active communication path, and a passive communication path. Various embodiments include one or more switching devices, one or more directional couplers, one or more diplexers, a power divider network, and/or an attenuator.

RF signal amplifiers are provided that include an RF input port, one or more active RF output ports, one or more passive RF output ports, an active communication path, and a passive communication path. Various embodiments include one or more switching devices, one or more directional couplers, one or more diplexers, a power divider network, and/or an attenuator.

A multi-level capacitive digital-to-analog converter, comprises at least one capacitor switch circuit (100) including a differential operational amplifier (130) having a first input node (E130a) and a second input node (E130b). A first current path (101) is coupled to a first reference input terminal (E100a) to apply a first reference potential (RefP) and the second current path (102) is coupled to a second reference input terminal (E100b) to apply a second reference potential (RefN). The at least one capacitor switch circuit (100) comprises a first controllable switch (111) being arranged between the second input node (E130a) of the differential operational amplifier (130) and the first current path (101). The at least one capacitor switch circuit (100) comprises a second controllable switch (112) being arranged between the first input node (E130a) of the differential operational amplifier (130) and the second current path (102).

A power amplifier module can include one or more switches, a coupler module, input signal pins, and a controller having first and second output terminals. The input signal pins can receive a voltage input/output signal, a clock input signal, and a data input signal. The controller can (i) set a mode of the one or more switches using a synchronous communication protocol in which the controller outputs a synchronous clock signal on the first output terminal and a data signal on the second output terminal, when the power amplifier module is in a first operating mode, or (ii) set a mode of the coupler module using an asynchronous communication protocol in which the controller outputs a first asynchronous control signal on the first output terminal and a second asynchronous control signal on the second output terminal, when the power amplifier module is in a second operating mode.

A power amplifier module can include one or more switches, a coupler module, input signal pins, and a controller having first and second output terminals. The input signal pins can receive a voltage input/output signal, a clock input signal, and a data input signal. The controller can (i) set a mode of the one or more switches using a synchronous communication protocol in which the controller outputs a synchronous clock signal on the first output terminal and a data signal on the second output terminal, when the power amplifier module is in a first operating mode, or (ii) set a mode of the coupler module using an asynchronous communication protocol in which the controller outputs a first asynchronous control signal on the first output terminal and a second asynchronous control signal on the second output terminal, when the power amplifier module is in a second operating mode.