A direct reading frequency measuring set

The principle employed in this equipment is, in the first stage, to heterodyne the signal with a known frequency derived from a source of standard frequency and to indicate a digit which is the first figure in the value of the signal frequency. The beat frequency from the first stage is passed to the second Stage, where it is heterodyned again with a lower standard frequency and the second digit indicated. This process is continued until the final stage is reached. The final stage is a deflectional type of frequency meter which indicates the remaining figures in the signal frequency value. The Paper therefore describes the problems involved in devising a system of the above kind, and their solution so that an unambiguous reading of the signal frequency is obtained, without thought on the part of the operator.