RECONFIGURABLE LOCAL OSCILLATOR FOR OPTIMAL NOISE PERFORMANCE IN A MULTI-STANDARD TRANSCEIVER

摘要

A transceiver for multi-standard operation (usable, for example, to communicate signals both of a first wireless communication standard and of a second wireless communication standard) has a mixer that receives a local oscillator signal generated by a local oscillator. A PLL of the local oscillator involves a VCO, a digitally programmable analog loop filter, a digitally programmable VCO supply voltage circuit, and a digitally programmable VCO varactor bias control circuit. In one aspect, the bandwidth of the analog loop filter is adjusted depending on the communication standard of the signal being communicated. In other aspects, the VCO supply voltage circuit and/or the varactor bias control circuit are configured in different ways to optimize PLL performance depending on the communication standard of the signal being communicated.