Abstract: A resonator for a rotary compressor is provided to prevent generation of impact exciting force and pulsation sound occurred due to pressure pulsation and reduce a noise of a low frequency band generated in the compressor by forming a curved portion at a narrow unit of the resonator which is a pressure pulsation inflow path and controlling the ratio of a diameter to a length of each of the narrow unit and a resonance unit, for thereby smoothing the inflow of the pressure pulsation generated from a pressure chamber. To achieve such a resonator, in a resonator for a rotary compressor, which consists of a narrow unit serving as an inflow path of pressure pulsation which is generated from a compressor and communicating with an exhaust outlet and a resonance unit for reducing a noise by attenuating the pressure pulsation element flowed through the narrow unit, the improved resonator for the rotary compressor according to the present invention includes a curved portion formed at an end portion of the narrow unit.

Abstract: A unique method and apparatus modifies the load impedance at the output of a power amplifier by varying a voltage variable capacitor (VVC) (310) to maximize the efficiency of the power amplifier (304). A comparator (509) generates amplifier control signal (211) based upon a detected power output signal (216) and a reference signal. In addition to providing power control, the control signal is also coupled to a VVC circuit (506) to control the output impedance of the power amplifier. In an alternate embodiment, a separate VVC control signal (527) based upon a comparison of the power control signal and the battery voltage is coupled to a VVC. In another alternate embodiment, a second VVC can be coupled in parallel to the first VVC. The second VVC is preferably controlled by a signal (805) based upon the current in the power amplifier.

Abstract: A portable radio transceiver (100) includes a transmitter (101) and a receiver (103) operating at different respective frequencies. The transmitter (101) is capable of producing an undesired signal (121) including a frequency substantially equal to the receiver operating frequency (107). A first antenna (102) is coupled to the transmitter (101). A second antenna (104) is coupled to the receiver (103) and electrically isolated (122) from the first antenna (102) by a predetermined degree such that the undesired signal (121) received by the second antenna (104) is attenuated by the predetermined degree of electrical isolation (122). An optional filter (112), coupled to an input terminal of an amplifier (113) in the transmitter (101), is adapted to attenuate the undesired signal (121) such that the undesired signal (121) received by the second antenna (104) is further attenuated.

Abstract: A unique method and apparatus modifies the load impedance at the output of a power amplifier by varying a voltage variable capacitor (VVC) (310) to maximize the efficiency of the power amplifier (304). A comparator (509) generates amplifier control signal (211) based upon a detected power output signal (216) and a reference signal. In addition to providing power control, the control signal is also coupled to a VVC circuit (506) to control the output impedance of the power amplifier. In an alternate embodiment, a separate VVC control signal (527) based upon a comparison of the power control signal and the battery voltage is coupled to a VVC. In another alternate embodiment, a second VVC can be coupled in parallel to the first VVC. The second VVC is preferably controlled by a signal (805) based upon the current in the power amplifier.