A continuous time sigma
delta modulator having minimal excess loop
delay. The continuous-time sigma
delta modulator in accordance with the present invention includes at least one
integrator stage coupled to receive an input
signal and a
resultant integrator output
signal from a previous stage for providing a
resultant integrator output. At least one output stage connects to the at least one integrator stage to receive the
resultant integrator output
signal from the previous integrator stage for providing a resultant integrator output. A
sample and hold circuit connects to receive the second integrator input signal. A multiplier connects to the
sample and hold circuit to provide a resultant sampled signal. An analog-to-
digital converter quantizer couples to receive the resultant sampled signal and to produce a quantized output signal. A digital modulation loop circuit connects to the analog-to-
digital converter quantizer to generate a resultant quantized output signal for correcting excess loop
delay in the continuous time sigma
delta modulator. A fourth feedback multiplier coupled to receive the resultant quantized output signal and produce a second resultant quantized output signal. A digital-to-analog converter coupled to receive the second resultant quantized output signal to produce a modulation feedback signal. A
delay connects to the digital-to-analog converter to receive the modulation feedback signal and provide the resultant modulation feedback signal