- on Miscellaneous Electronics
- Published in issue 11/2013 on page 70
Freystedt’s Audio-Frequency Spectrometer (1935)
Restoration of a landmark in electro-acoustic measurement technology! As opposed to time consuming mechanical, optical and graphic/mathematical methods, electronic engineering in the mid-1930s brought new possibilities to sound analysis. Filter circuits allow individual frequencies and frequency bands to be stressed or suppressed. The ‘search frequency’ method allows highest resolution to be achieved at constant absolute bandwidth, but at the expense of analysis speed.