| 摘要 |
627,486. Frequency analysis. TOMLINS, F. C. (Western Electric Co., Inc.). Dec. 7, 1945, No. 33177. [Class 37] [Also in Groups XV, XXXVIII and XL (a)] A complex wave is analysed into its component frequencies, the intensity and time of occurrence being visibly indicated. As applied to speech waves, the corresponding electric signal is applied to modulate the intensity of a cathode - ray beam through a frequency analyser 4, 5, 6, Fig. 1, the beam being deflected across the screen once for each traverse of the frequency range so that each component frequency is represented by a dot whose position vertically of the screen corresponds to frequency and whose intensity corresponds to magnitude of frequency. The cathode-ray screen rotates so as to give an indication of the times of occurrence, duration and cessation of each component frequency. The record shown in Fig. 2 is said to correspond to the word "two" and may be used to instruct deaf persons to articulate or assist them to under. stand sounds. In a modification, Fig. 3, the cathode-ray beam may move in a circular orbit to provide the indication of times of occurrence, duration and cessation, the tube being rotated in the opposite direction to provide a stationary viewing area 2. Permanent records may be made by recording the sound, e.g. by magnetizing a tape 33, Fig, 4, and repeatedly heterodyning the signal produced thereby and passing it through a filter 5 to produce a record by a stylus 40 on paper round a drum 31, the rotation of the drum varying the frequency of the heterodyning oscillation 3, so that each component frequency is recorded individually on an appropriate line of the record. |
