| 摘要 |
Stereo headphones for use in conjunction with a hi-fi system rely on infra-red signals transmitted by the system. The headphones comprise a first unit, containing an infra-red sensor 42, and loudspeakers 41, which is worn on the head, and which is connected 44 to a second unit by means of a cable 43. The second unit contains demodulator 72, amplifier 73, batteries 74, frequency selector 58 and volume control 57, and can be carried or worn where desired. The weight on the user's head is reduced by this arrangement. An alternative arrangement (figs 5 and 6) has a single earphone. <IMAGE> |
