Patent ID: 6542097
Filing Date: 2003-04-01
Classification: H03M

Abstract:
A data conversion device of a delta modulation type, comprising:a comparator for comparing a sinusoidal analog input signal with a reference voltage to convert the input signal into a binary digital signal; and a reference voltage supplying circuit for feeding the reference voltage to the comparator, said reference voltage supplying circuit comprising: a current output circuit for outputting a current and varying a direction and a magnitude of the output current; a current-to-voltage conversion circuit for converting the current output from the current output circuit into a voltage and feeding the voltage to the comparator; an absolute value signal generating circuit for feeding the current output circuit with an absolute value signal that governs an absolute value of the current output from the current output circuit; an up/down circuit for determining, on a basis of an output of the comparator, whether to increase or decrease the magnitude of the current output from the current output circuit and feeding a signal representing a result of the determination to the absolute value signal generating circuit; and an up/down value output circuit for outputting an up value and a down value on a basis of a signal output from the absolute value signal generating circuit and the signal output from the up/down circuit, wherein, when the absolute value signal is large, the up/down value output circuit decreases the up value, by which the absolute value signal is to be increased, and increases the down value, by which the absolute value signal is to be decreased.