Modern communication devices, such as 802.x enabled communication devices, may utilize a conventional transceiver to transmit and/or receive signals with variable signal strength. One or more voltage controlled oscillator (VCO) circuits may be utilized within the conventional transceiver to generate oscillator reference signals with a specific output frequency and/or phase. The generated oscillator reference signals may then be utilized by a transmitter and/or by a receiver within the 802.x enabled device to facilitate processing of a received signal and/or processing of a signal prior to transmission.
The signal strength of a processed signal within a conventional transceiver varies depending on the distance between a transmitter and a receiver circuit, as well as environmental factors and process, temperature, etc. variations (PTV). A power amplifier may be utilized prior to signal transmission by a transmitter, for example, and a variable gain low noise amplifier may be utilized after a signal is received by a receiver, to amplify the signal and adjust the signal gain accordingly. In addition, reference signals generated by the voltage controlled oscillator circuits may also need to be calibrated due to variations caused by environmental factors and process, temperature, etc. variations.
The voltage controlled oscillator circuits within the conventional transceiver may be adapted to generate one or more differential frequency output signals and may be followed by one or more divider circuits, for example, that divide the generated differential frequency output signals for subsequent use by other circuits within the transceiver. The voltage controlled oscillators, however, are sensitive to loading from following divider circuits and/or other interconnections. Large capacitance from loading and/or resistance created by dividers and line routing decrease the quality factor and limit performance of the voltage controlled oscillator circuits within the transceiver.
In this regard, the desired output frequency of the differential output signal generated by the voltage controlled oscillator may change and re-calibration may be required. In addition, variations caused by environmental factors and PTV may result in deviations in the desired output frequency of the differential output signals generated the VCO circuits. Consequently, re-calibration of the voltage controlled oscillator may be required in order to generate output differential signals with desired output frequency. Calibration circuits, however, require significant on-chip real estate for handling additional re-calibration function. Further, conventional methods for calibrating the output frequency of the voltage controlled oscillator circuits may be time-consuming and/or inaccurate resulting in reduced overall processing efficiency of the transceiver.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.