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AssigneeKoninklijke Philips Electronics N.V.
InventorsMatthias Locher, Leonardo Della Pietra
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The circuit arrangement has a sigma-delta converter (2) for converting an analog input signal into a digital output signal. The sigma-delta converter (2) contains a loop filter, a comparator connected downstream of the latter and a feedback loop to feed the output signal back to the input signal. To reduce idle tones a dither signal is fed to the comparator by means of a dither-signal line (27.1). The dither signal is not however generated by a complex dither-signal generator. Instead, what is used as a dither signal is a signal that is available in the circuit but is not specifically generated for this purpose, e.g. an output signal from a second sigma-delta converter (2′). The circuit arrangement is thus simpler and less expensive than conventional circuit arrangements without its reduction of idle tones suffering.
A circuit arrangement having a sigma-delta converter (2) for convening an analog input signal into a digital output signal, wherein the sigma-delta converter (2) comprises a loop filter (22) having a filter input to which an input line (21) for the input signal is connected and having a filter output, a quantizer (23) having a quantizer input that is connected to the filter output and having a quantizer output to which an output line (24) for the output signal is connected, and a feedback loop (25) to feed the output signal back to the input signal, and the circuit arrangement has a dither-signal line (27) that is suitable for additionally applying to the quantizer input, as a dither signal, a signal tat is available in the circuit without a separate dither generator.
A method for the sigma-delta conversion of an analog input signal into a digital output signal comprising the following method steps:
Dependencies are inferred from the claim text.