US 2002/0175847 A1 · Delta sigma type AD converter

Abstract

On a first stage of the delta sigma type AD converter for quantizing an input analog signal, converting it to an output digital signal, and outputting, the computing element adds a feedback signal from a second stage DA converter and subtracts a feedback signal in which the output of the delay unit is multiplied at a coefficient α with a coefficient buffer and a feedback signal from the delay unit, the input analog signal is output to a computing element on a post stage, and on the second stage, feedback by a coefficient β, different from a coefficient α, is executed. The frequency characteristic of quantization noise Q(Z) selects coefficients α, β so appropriately that transmission zero points are provided above and below the central frequency of an input analog signal, and the quantization noise can be damped in the range of a wide bandwidth.

Claims11

Dependent claims

A delta sigma type AD converter for quantizing an input analog signal, converting it to an output digital signal, and outputting, comprising:

a signal processing device which executes filter processing corresponding to a transmission function upon said input analog signal;
and
a quantizing device which quantizes the input analog signal subjected to said filter processing with a sampling frequency, converts it to the output digital signal, and outputs,
wherein the frequency characteristic of quantization noise in said quantizing device has a first transmission zero point on the side of lower frequencies than the central frequency of said input analog signal and a second transmission zero point on the side of higher frequencies of said input analog signal.

1 more element

Dependencies are inferred from the claim text.

Delta sigma type AD converter

Life of this patent

Delta sigma type AD converter

Life of this patent

Abstract

Claims11