<div class="description">
<p>In the parallel-wire system employed by the Bureau of Standards for frequency standardisation a valve generator is used for excitation, and a current-indicating instrument of low resistance is used as a bridge across the wires [see Abstract 1925B00309]. The present paper gives a complete mathematical treatment of the method; which is based on resonance conditions. The settings are therefore sharp, and it is possible to approach the theoretical accuracy in actual operation. The frequency /b f/ in kilocycles per second is calculated from a length /b l/ measured along the wires by means of the equation /b f/ = /b v/ /sub 0/ (1 -  Delta )/2/b l/, where /b v/ /sub 0/ is the velocity of light and /b l/ is the distance in metres between two consecutive maximum settings. The correction factor  Delta  is always small; a formula enables  Delta  to be calculated from the dimensions of the system. It is found best to keep the wires as short as possible, and just long enough to enable two maximum settings to be made. By connecting a small condenser across the input terminals, both maximum settings can be moved closer to the input end without changing the distance between them. The thermoelectric instrument used as detector, which is shunted by a wire of low resistance, does not affect the settings appreciably.
</p>
<br>Subjects:</div>
<div class="fn value">
Hund, A.</div>
Internet Archive identifier