Patent ID: 8639206
Filing Date: 2014-01-28
Classification: G06F,H03D

Abstract:
1. A mixer apparatus comprising: a first mixer circuit configured to generate a first output signal from an input signal, based on repeatedly clocking through a sequence of sample values representing one period of a sinusoidal local oscillator waveform and having a sequence length corresponding to an oversampling rate of the sequence; a second mixer circuit configured to generate a second output signal from a second input signal, based on repeatedly clocking through a shifted sequence, which is the sequence as shifted by an integer number of sequence positions that is equal to one quarter of the sequence length for a first case where the sequence length divides by four, or is as close to one quarter of the sequence length as possible for a second case where the sequence length divides by two but not by four; and a control circuit configured to maintain a quadrature phase relationship between the first and second mixer circuits independent of whether the first or second case applies by controlling the second mixer circuit to clock coincident with the first mixer circuit if the first case applies, and to clock a half clock cycle out of phase with the first mixer circuit if the second case applies.