Abstract: A technique for implementing impedance matching circuits 100 that use the transfer functions of each line impedance model. This technique allows implementation of an impedance match for a diverse number of line impedances reusing the same circuit 100 topology, by simply adjusting coefficients to accommodate different line impedances.

Abstract: A simple, power efficient and inexpensive digital compensation scheme for reducing delay in a digital impedance matching circuit to improve return loss. The scheme employs a digital filter to compensate for the absolute sampling and digital delays associated with a digital impedance matching circuit. The digital filter is based on the low-pass function of a DAC response, and can easily be modified to correct for not only the DAC response delay, but also other delays in the digital impedance matching circuit. The digital filter is very simple to implement and can add or subtract delays from the overall system.

Abstract: A technique for implementing impedance matching circuits 100 that use the transfer functions of each line impedance model. This technique allows implementation of an impedance match for a diverse number of line impedances reusing the same circuit 100 topology, by simply adjusting coefficients to accommodate different line impedances.

Abstract: A simple, power efficient and inexpensive digital compensation scheme for reducing delay in a digital impedance matching circuit to improve return loss. The scheme employs a digital filter to compensate for the absolute sampling and digital delays associated with a digital impedance matching circuit. The digital filter is based on the low-pass function of a DAC response, and can easily be modified to correct for not only the DAC response delay, but also other delays in the digital impedance matching circuit. The digital filter is very simple to implement and can add or subtract delays from the overall system.

Abstract: A hand-held electric curling iron has a hollow elongated barrel selectively insertable sequentially into one of a plurality of different diameter cylindrical hair rollers during the process of curling hair. The barrel communicates with an electric heater-blower assembly in the curling iron handle and has a plurality of apertures along its length for delivering a stream of heated air radially outwardly into the interior of the roller for heating the hair wound thereon. Each roller is provided at its ends with projecting collars for receiving and locating the barrel within the roller with a circumferential gap between the perforated portion of the roller and the barrel. The collars have circumferential apertures which cooperate with a retaining clip on the handle for securing the roller in place during use.