| 摘要 |
The present invention provides an active low-pass filter system including a low-pass filter circuit (22, 24, 26, 28, 30) and at least one frequency-rejecting network (20) coupled to the low-pass filter circuit. The frequency-rejecting network (20) is included in a resistive forward signal flow branch of the low-pass filter. The present invention also provides a power amplifier system (40) for driving a load (45). The power amplifier system (40) includes a pulse width modulation circuit (42) which creates ripple spectra, an error amplifier and modulator circuit (43), and a demoldulation filter (47) connected in series, and a feedback control loop coupled to the pulse modulation circuit (42) and including an active low-pass filter (44, 46) having a feedback demodulation filter (44) and an isolated-integrator frequency-rejecting network (20). |
