An on-chip concurrent high frequency analog and digital sinusoidal generator

A sigma-delta (/spl Sigma//spl Delta/) modulation based sinusoidal signal generator is exploited which can produce high frequency analog and digital signals concurrently. Except for a 1-bit DAC and band-pass filter, the circuits are entirely digital circuits. Using digital circuits, it is easier to integrate the function in silicon and verify itself. Also, signal amplitude and oscillation frequency can be precisely controlled compared with pure analog signal generator. The area of the proposed high frequency sinusoidal signal generator is low and thus it is suitable to be a built-in signal generator for mixed-signal ICs testing.