ANALOG/DIGITAL CONVERSION METHOD AND SYSTEM

摘要

PROBLEM TO BE SOLVED: To simultaneously perform the frequency conversion of analog signals and band-pass filtering by an A/D converter provided with a voltage controlled oscillator(VCO) and a counter. SOLUTION: The analog signals including a carrier are inputted to the VCO 12 of the A/D converter 10 and the VCO generates a series of high frequency pulses based on the characteristics of the analog signals. A gate circuit 14 is turned ON/OFF corresponding to gate control signals set corresponding to the characteristics of the analog signals and the high frequency pulses made to pass through the gate circuit from the VCO are counted in a counter circuit 16. The counter circuit is reset at each sampling cycle including the plural pulses of the gate control signals and starts new accumulation.