Mystery Japanese sine wave diagram
Occasionally the Official Records team comes across a document that leaves us completely baffled; this is one of them.
Back when I started at the Memorial in January 2012 this was one of the items that were waiting for me. After asking around nobody appeared to know anything about it.
It is almost certainly Japanese in origin due to the Japanese writing on it; and due to the age and paper is most likely to be of Second World War vintage. Presumable it is a captured document.
It is of fragile paper which has both browned and has some liquid staining. The dimensions are 300x50mm. The paper appears to have a grey/blue graph design printed on it, presumable so that it can be used for mathematical/scientific data plotting. Written on it are two opposite pencilled sine waves, superimposed on the sine wave that starts in the +ve zone is a black penned sine wave which does not match the pencilled one. Along the length of the black penned wave are several “x” marks in blue pen, presumably these represent data that was taken. Along the centre line of the X axis of the graph are a series of numbers form 2-34 in increments of 2. On the Y axis the symbols 0+, 0 and (indistinct character)-. On the top and bottom are Japanese characters which have been translated as “Correction curve” on the top and “Error curve” on the bottom. There are also some more characters on the bottom, but these are indistinct; it has been suggested these characters may be a name.
The paper was backed by a piece of greyish backboard, which has broken three quarters of the length along. The backboard has a hole with a short piece of thick string attached. It appears as if the sting could be used to loop around a person’s wrist so that the item would be easy to carry and access for note taking.
So far nobody has been able to identify what the item is for. It is conceivable that it was used in Radio or Radar testing of some kind, but that is educated guesswork.
If anyone has any idea of what this document is please leave a comment, anything constructive is welcome.