Local oscillator apparatus and method
AssigneeBroadcom Corporation
InventorAlexandre Kral
Life of this patent
Estimating the term…
Abstract
A direct conversion satellite tuner is fully integrated on a common substrate. The integrated tuner receives an RF signal having a plurality of channels and down-converts a selected channel directly to baseband for further processing. The integrated tuner includes on-chip local oscillator generation, tunable baseband filters, and DC Offset cancellation. The integrated tuner can be implemented in a completely differential I/Q configuration for improved electrical performance. The entire direct conversion satellite tuner can be fabricated on a single semiconductor substrate using standard CMOS processing, with minimal off-chip components. The tuner configuration described herein is not limited to processing TV signals, and can be utilized to down-convert other RF signals to an IF frequency or baseband.
Claims14
A local oscillator generation circuit, comprising:
- a substrate;
- and
- a plurality of voltage controlled oscillators (VCOs) disposed on said substrate, each of said VCOs configured to generate a differential local oscillator (LO) signal over a different frequency band;
- wherein one of said VCOs is selected to provide an output LO signal based on a desired frequency for said output LO signal.
A local oscillator generation circuit, comprising:
- a substrate;
- a plurality of voltage controlled oscillators (VCOs) disposed on said substrate, each of said VCOs configured to generate a differential local oscillator signal over a different frequency band so that the plurality of VCOs cover a plurality of frequency bands;
- a plurality of amplifiers disposed on said substrate, receiving outputs from said plurality of VCOs;
- and
- a polyphase circuit that receives outputs from said plurality of amplifiers, and generates a quadrature output LO signal based on one of said outputs of said amplifiers;
- wherein one of said VCOs is selected for said quadrature output LO signal by enabling one of said plurality amplifiers that corresponds to said selected VCO, and disabling one or more of said plurality of amplifiers that do not correspond to said selected VCO.
The local oscillator generation circuit 8, further comprising a LO correction circuit that is configured to adjust an amplitude level of said quadrature output LO signal.
A method for generating a local oscillator signal for a receiver, comprising:
- generating a plurality of local oscillator signals;
- outputting said plurality of local oscillator signals to a plurality of corresponding amplifiers;
- enabling one of said amplifiers to select one of said local oscillator signals for tuning said receiver, and disabling the other amplifiers;
- and
- tuning a frequency of said selected local oscillator signal.
Dependencies are inferred from the claim text.