| 摘要 |
1,102,779. Recording and playback. WESTERN ELECTRIC CO. Inc. 27 May, 1965 [5 June, 1964], No. 22516/65. Heading G5R. [Also in Division G1] In an apparatus for analysing complex signals carried on a magnetic tape 101 (Fig. 1) a portion of the tape is fed from a reel 10 to a supply reel 21 via sensing head 12 and periodically stopped on the periphery of a drum 17 and repeatedly scanned, by a head rotating inside the drum. During each rotation at a particular stop, the output signal is modulated by a different frequency, the resulting beat frequency being filtered by a fixed frequency filter, to provide an output corresponding to a particular frequency in the spectrum of the original signal. The selected portion of tape is clamped under tension at each step, it being arranged that the operation of the tensioning system is delayed relative to the clamp at each stop. The tensioning and clamping system is released and the record advanced by a preselected interval after the portion has been analysed in order to select the next contiguous portion of the record. The outputs are successively recorded by a stylus 22 on a record 39 carried on a drum 23 rotated in synchronism with the rotating head. The amplitude of a mark on the record 39 corresponds to the signal amplitude at any particular frequency, the frequency corresponding to the position across the medium, while distance along the medium corresponds to time. A more detailed description of the operating system circuitry is given (see Division G1). |
