| US 7,579,891 B2 | ||
| Method and circuit arrangement for generating a periodic electric signal with controllable phase | ||
| Christian Ebner, Munich (Germany) | ||
| Assigned to National Semiconductor Germany AG, Unterhaching (Germany) | ||
| Filed on May 08, 2007, as Appl. No. 11/745,790. | ||
| Claims priority of application No. 10 2006 023 695 (DE), filed on May 19, 2006. | ||
| Prior Publication US 2007/0268060 A1, Nov. 22, 2007 | ||
| Int. Cl. H03H 11/16 (2006.01) | ||
| U.S. Cl. 327—237 | 8 Claims |
| 1. A method for generating an electric output signal (sout) with a specified frequency and an output phase (P) dependent upon
a control signal (x), comprising the steps
generating, in response to the control signal (x), a first phase interpolation signal (s12) comprising a weighted superposition of a first input signal (s1) and a second input signal (s2), wherein the first and second input signals (s1, s2) have the specified frequency, but different input signal phases,
generating, in response to the control signal (x), a second phase interpolation signal (s12*) comprising a weighted superposition of a third input signal (s1*) and a fourth input signal (s2*), wherein the first and second input signals (s1, s2) have the specified frequency, but different input signal phases,
wherein the phase difference between the first input signal (s1) and the second input signal (s2) is substantially equal to the phase difference between the third input signal (s1*) and the fourth input signal (s2*), and wherein the third and fourth input signals (s1*, s2*) are phase-shifted by substantially one half of said phase difference between the first and second input signals (s1, s2),
such that the phase of the first interpolation signal (s12) and the phase of the second interpolation signal (s12*) are substantially equal to the output phase (P), and
generating the output signal (sout) as a superposition of the first and second interpolation signals (s12, s12*).
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