A Laboratory Frequency Standard
G. P. Harnwell, J. B. H. Kuper · Review of Scientific Instruments · 1937
An inexpensive laboratory frequency standard consisting of a crystal-controlled clock and auxiliaries has been constructed and thoroughly tested. Standardized by the signals from WWV, it permits the measurement of radio and audiofrequencies to one part in 105 or better and also furnishes second ticks for laboratory timing.