Patent ID: 7433667

Claim:
A signal conditioning circuit for providing a complex output signal having a first component (I or f OUT1 ) at a first tap and a second component (Q or f OUT2 ) at a second tap, comprising: an oscillator circuit for providing a signal at a first frequency (f OSC ); a first conversion device, comprising: a first input operatively coupled to the oscillator circuit, a second input, and an output which forms the first tap of the signal conditioning circuit, with the first conversion device converting the frequency of signals applied to its inputs to an output signal; a second conversion device, comprising: a first input operatively coupled to the oscillator circuit, a second input, and an output which forms the second tap of the signal conditioning circuit, with the second conversion device converting the frequency of signals applied to its inputs to an output signal; and a frequency divider circuit, comprising: a sigma-delta modulator having a division ratio associated therewith for producing signals using fractional division ratios, a signal input that is operatively coupled to the output of the first conversion device so as to form a feedback path, wherein a filter device is provided in the feedback path, a first signal output operatively coupled to the second input of the first conversion device and providing a first signal with a first phase and at a first frequency which is a function of the frequency of a signal applied to the signal input of the frequency divider circuit and the division ratio of the frequency divider circuit, and a second signal output operatively coupled to the second input of the second conversion device and providing a second signal at the frequency of the first signal and with a second phase which has been shifted through one or more degrees with respect to the first phase of the first signal.