1. Field of the Invention
The present invention relates to an analog-digital converting device for converting analog quantities into digital quantities, especially to an analog digital converting device for converting many analog inputs into digital quantities at one time.
2. Description of the Prior Art
In known A-D converters which convert analog quantities into digital quantities, a comparator receives each analog voltage along with reference signals from separate reference generating means and compares the analog quantities to the reference values while separate pulse generators pass pulse signals through separate gates. When the reference values equal the analog values the comparators turn off the gates. The analog quantities are then represented by the number of pulses passing through the gates.
In order to convert a number of analog quantities into digital quantities by means of such devices, the number of reference signal sources as well as pulse sources must correspond with the number of analog quantities to be converted. It is also essential that the characteristics of the reference signal sources be identical, and that the pulse sources be identical. This results in space consuming and expensive converters.
This creates a particular problem in cameras attempting to utilize such systems, because the amount of space in a camera is usually limited to keep its size and weight at a minimum.