Abstract: Disclosed are, inter alia, a sound absorption and insulation material including a polyester hollow fiber, a polyester low-melting-point composite fiber and a polyester base fiber, a sound absorption and insulation pad for a floor including the same, and a manufacturing method thereof for improving the elasticity and sound absorption and insulation performance of the sound absorption and insulation material. The sound absorption and insulation material is an environmentally friendly material that can reduce discomfort due to the generation of volatile organic compounds (VOCs) and the emission of toxic gases during combustion. Also, the sound absorption and insulation pad including the sound absorption and insulation material can exhibit superior sound absorption performance, sound insulation performance and actual vehicle performance compared to a conventional sound absorption and insulation pad of the same thickness.

Abstract: A feedback signal cancellation apparatus includes a first RF receiver configured to down-convert a received RF signal to a predetermined frequency band, a subtractor configured to subtract a replica of a feedback signal from the down-converted signal, a transmission signal generator configured to generate a repeater output signal using a feedback cancelled signal, a RF transmitter configured to transmit the repeater output signal, a second RF receiver configured to down-convert a RF signal outputted from the RF transmitter to a predetermined frequency band, a reference signal generator configured to receive the RF signal and generate a reference signal having no DC pilot, and a replica generator configured to generate a filter coefficient using correlation between the feedback cancelled signal and the reference signal and to generate a replica of the feedback signal using the generated filter coefficient and the down-converted signal of the second RF receiver.