A selective low noise amplifier (LNA) comprising an input hybrid coupler receives a first input and a second input and to provide a first output and a second output; and an output hybrid coupler receives a first input and a second input and to provide for at least one output. A first amplifier and a second amplifier, each respective amplifier in first and second parallel paths are couple to and between the first output and the second output, respectively, of the input hybrid coupler and the first input and the second input, respectively, of the output hybrid coupler. A phase controller coupled to at least one of the first input and the second input of the output hybrid coupler delays signals from the first and second inputs of the output hybrid coupler to the at least one output of the output hybrid coupler. A method is also disclosed.

A selective low noise amplifier (LNA) comprising an input hybrid coupler receives a first input and a second input and to provide a first output and a second output; and an output hybrid coupler receives a first input and a second input and to provide for at least one output. A first amplifier and a second amplifier, each respective amplifier in first and second parallel paths are couple to and between the first output and the second output, respectively, of the input hybrid coupler and the first input and the second input, respectively, of the output hybrid coupler. A phase controller coupled to at least one of the first input and the second input of the output hybrid coupler delays signals from the first and second inputs of the output hybrid coupler to the at least one output of the output hybrid coupler. A method is also disclosed.

An electrolarynx includes tone-producing circuitry, a power switch to turn on the circuitry, a control button (i.e., a pushbutton) to actuate the power switch, a pressure-sensitive-resistor (PSR) that is physically coupled to the pushbutton, and a mode switch. PSR resistance is dependent on the amount of pressure applied to the pushbutton, and the tone-producing circuitry is configured to respond to such variations in PSR resistance according to a user-selected mode of electrolarynx operation set by operation of the mode switch. Said modes preferably include multiple frequency-varying modes (FVMs) in which the frequency of the electrolarynx tone is varied with different sensitivities to variations in PSR resistance, and multiple volume-varying modes (VVMs) having different sensitivities. A preferred embodiment also includes a communications-link mode, for receiving control information from an external device, and a disabled mode. Preferably, the tone-producing circuitry includes a microcontroller component that is configured for electrolarynx operation under program control.