Abstract
This paper describes a new method of pulse width modulator which can be read out nondestructively by a square wave voltage of comparatively low frequency (here 50Hz). The modulator is constructed from two-hole elements which are made by laminating a sheet of core of Fe-Ni 50% permalloy with square loop properties. The memory holding characteristics of this modulator were investigated experimentally in detail. Then it became clear as a result that there are two modes in the mechanism of the write-in and the readout. The linearity of the readout pulse width characteristics becomes better if the amount of the flux written in is controlled by the constant voltage by means of negative feedback. The difference of the first pulse width from the second one which was read out at a drive time is especially larger than the difference of the second from the third, etc. Then this second readout pulse width was selected as the standard one, and the memory holding characteristics were represented by the difference between the readout pulse width and standard one for the number of the readout.
The adequate selection of the compensation winding and the bias voltage can make this difference within ±0.5%. The use of the write-in method due to the feedback setting can make this difference within 0.25% in the range of 1, 000 times of the readout.
