Through analysis and comparison of equivalent random sampling and equivalent sequential sampling

present a design proposal for 10 MHz AC millivoltmeter. The fount-end adjusting circuit modulates the signal to an appropriate amplitude

then field programmable gate array（ FPGA） drives the ADC chip to achieve equivalent sampling

the final measured value is calculated after microprogrammed control unit（ MCU） processing the sampled data. Test results shows that the signal under 10 MHz can be restored and the effective value of the signal can be measured precisely by using the ADC chip of 1 MHz sampling frequency.