| 摘要 |
A continuous-time smoothing filter circuit and method for implementing the same are disclosed. The circuit may be implemented as a cascade of two sections. The first section may comprise two programmable 3rd order low-pass filters, each filter having a low Q value complex pole pair, as well as, a negative real pole. The second section may comprise an output stage amplifier having a low output impedance in order to drive external loads. Each of the 3rd order low-pass filters may be under programmable control to select and coarsely tune the cut-off frequency for each of the two filters. In its broadest terms, the method of the present invention can be described as: processing a digital to analog converter generated output signal with a first 3rd order low-pass filter; processing a first output signal provided by the first 3rd order low-pass filter with a second 3rd order low-pass filter; and processing a second output signal provided by the second 3rd order low-pass filter with a low-output impedance amplifier.
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