DEVICE HAVING A DELTA-SIGMA MODULATOR AND A SWITCHING AMPLIFIER CONNECTED THERETO

摘要

A delta-sigma modulator for a switching amplifier, which achieves a high signal-to-noise ratio (SNR) in the multi-MHz range and keeps the noise-transfer function over the useful frequency range as low and as flat as possible. A series connection of a parallel-serial converter and a downstream swap element for the serial output signal ya2 of the parallel serial converter is connected to the multi-bit output of the delta-sigma-modulator. The swap element swaps, based on the last bit value 0 or 1 of a preceding word in the resulting output signal ya3, the sequence of the binary zeroes and ones of the current word, where present, and then an input signal is fed to the delta-sigma-modulator. The signal is capable of having a frequency range above 25 kHz, and is prepared with a low oversampling ratio and a high SNR. And, 1-0 or 0-1 transitions are largely eliminated at the word boundaries.

主权项

1. An apparatus comprising a delta-sigma modulator and a switching amplifier connected thereto, wherein at a multi-bit-output of the delta-sigma-modulator a series connection of a parallel-to-serial converter and a subsequent swap element for a serial output signal ya2 of the parallel-serial-converter are connected, and wherein the swap element, based on a last bit value 0 or 1 of a preceding word in a resulting output signal ya3, reverses a sequence of binary zeroes and ones of a current word, where present, whereby an input signal is fed to the delta-sigma-modulator, said signal being capable of having a frequency range above 25 kHz, is prepared with an oversampling ratio that lies between 7 and 15, and a high signal-to-noise ratio such 1-0 or 0-1 transitions at word boundaries are substantially eliminated.