| 摘要 |
In a modulator circuit, a mapping function is performed within a main feedback loop of the modulator, rather than after the feedback loop. In a high-fidelity digital modulator embodiment, pulse width modulation mapping generates a fairly large harmonic content when cascaded with the digital modulator circuit and tends to dramatically change the shape of the noise floor in the desired band, e.g. 0-40 kHz. Placing the mapping function within the modulator feedback loop tends to compensate for non-linear features of the mapping function, thus reducing harmonic generation and simplifying the task of suppressing harmonic generation to an acceptable level. In addition to reducing harmonic generation, this arrangement simplifies feedback processing and the accumulation of feedback information within various integrators in the modulator circuit.
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