PURPOSE: To simplify the circuit constitution and easily integrate the circuit by converting an input analog signal into a digital signal through a delta modulator and passing the conversion output through an out-band noise removing filter after its offset is removed.
CONSTITUTION: The input analog signal is inputted to the delta modulator 7 consisting of a comparator 8, delay device 9, and RC integrator and converted into a one-bit digital signal by the modulator 7. The output of the modulator 7 is inputted to the offset removing circuit part 10 consisting of a delay device 11 and a full adder 12 to remove offsets of noises and data of the sampling frequency of the one-bit data, and inputted to a cyclic digital filter 13 in the form of N-bit data. A filter part 13 consists of M stages of cyclic digital filters 14 and removes out-band noises completely and outputs an N-bit digital signal. The modulator 7 has high the sampling frequency, so the band of the analog signal which is converted is wide and the integration is easily attained because of simple circuit constitution.
SOBASHIMA AKIRA
NURIYA KOUZOU
| JPS5972225A | 1984-04-24 | |||
| JPS59160321A | 1984-09-11 |