DEVICE AND METHOD FOR SYNCHRONIZING DATA ACQUISITION DEVICE WITH HOST

摘要

PROBLEM TO BE SOLVED: To minimize an increase of the complexity of both device hardware and software and to re-establish synchronism by synchronizing the reference clock signal received from a host device with the A/D converter clock signal generated by a data acquisition pod. SOLUTION: An A/D converter 220 is a sigma-delta type and digitizes samples of an analog signal at an extremely high rate to generate multibit digital samples of a lower rate. A pulse modulation digital phase-locked loop device 226 decodes synchronous parts of successive frames received from a monitor through a link 12 to receive a host reference signal 228 derived from an interface 210 and an A/D reference clock signal 230 generated by a crystal oscillator 232. Then an A/D clock signal 234 synchronized with the frequency of the host reference signal 228 is developed.