A built-in-self test (BIST) scheme for analog circuitry functionality
tests such as frequency response, gain, cut-off frequency,
signal-to-noise ratio, and linearity measurement. The BIST scheme
utilizes a built-in direct digital synthesizer (DDS) as the test pattern
generator that can generate various test waveforms such as chirp, ramp,
step frequency, two-tone frequencies, sweep frequencies, MSK, phase
modulation, amplitude modulation, QAM and other hybrid modulations. The
BIST scheme utilizes a multiplier followed by an accumulator as the
output response analyzer (ORA). The multiplier extracts the spectrum
information at the desired frequency without using Fast Fourier Transform
(FFT) and the accumulator picks up the DC component by averaging the
multiplier output.