VII. A self-contained standard harmonic wave-meter

Open Access
Publisher Website
Google Scholar
Abstract
Following a brief introductory survey of the various methods of measuring radio-frequency, the principles of a highly accurate standard harmonic wave-meter are developed. The essential principle is an arrangement of three-electrode valves, known as a multi-vibrator, the invention of H. Abraham and E. Bloch. The arrangement produces a discontinuous wave, the frequency of which may be adjusted to have any value within very wide limits. When a current of such wave form acts by induction on another circuit, this circuit receives what may be considered as a series of electrical blows at equal intervals of time. If the circuit operated upon is highly resonant, then when its resonant frequency is set so as to be an integral multiple of the frequency of the blows, a large oscillatory current is built up, of a persistent kind and of a frequency whose ratio to that of the blows is quite exact.