Patent ID: 7116254
Filing Date: 2006-10-03
Classification: H03M

Abstract:
1. A complex type sigma-delta analog to digital conversion unit, comprising: a first subtractor for carrying out subtraction by inputting a first input signal and a first feedback signal; a first filter for filtering an output signal of the first subtractor; a first analog to digital converter for converting an output signal of the first filter into a digital format from an analog format; a first digital to analog converter which converts an output signal of the first analog to digital converter into an analog format from a digital format and outputs the converted signal to the first subtractor as the first feedback signal; a second subtractor for carrying out subtraction by inputting a second input signal and a second feedback signal, the second input signal being orthogonal to the first input signal; a second filter for filtering an output signal of the second subtractor; a second analog to digital converter for converting an output signal of the second filter into a digital format from an analog format; a second digital to analog converter which converts an output signal of the second analog to digital converter into an analog format from a digital format and outputs the converted signal to the second subtractor as the second feedback signal; a first sign controller which inverts a positive/negative sign of the output signal of the first filter in response to a control signal and outputs it to the second filter; and a second sign controller which inverts a positive/negative sign of the output signal of the second filter in response to the control signal and outputs it to the first filter.