| US 7,538,631 B2 | ||
| Multi-mode amplitude modulator control method | ||
| Antti Immonen, Helsinki (Finland); and Vlad Grigore, Espoo (Finland) | ||
| Assigned to Nokia Corporation, Espoo (Finland) | ||
| Filed on Feb. 20, 2007, as Appl. No. 11/707,886. | ||
| Claims priority of application No. 20065865 (FI), filed on Dec. 29, 2006. | ||
| Prior Publication US 2008/0157895 A1, Jul. 03, 2008 | ||
| Int. Cl. H03C 1/00 (2006.01) | ||
| U.S. Cl. 332—149 [332/159; 332/160; 332/178] | 39 Claims |
| 1. A parallel-hybrid amplitude modulator apparatus, comprising:
an interface configured to receive an input signal;
a linear part configured to track frequency components of the input signal above a determined threshold frequency;
a switching part arranged in parallel with the linear part and configured to track frequency components of the input signal
below the determined threshold frequency,
wherein the linear part and the switching part are configured to track a varying amplitude of the input signal; and
a current sensing and controlling part configured to determine a level of a direct current component at an output of the linear
part and control the switching part to produce an output signal configured to compensate the direct current component at the
output of the linear part to decrease a absolute level of the direct current at the output of the linear part.
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