Voltage-controlled oscillator

About: Voltage-controlled oscillator is a research topic. Over the lifetime, 23896 publications have been published within this topic receiving 231875 citations. The topic is also known as: VCO.

Method and apparatus for calibration of a low frequency oscillator in a processor based system

Abstract: Method and apparatus for calibration of a low frequency oscillator in a processor based system. A method for calibrating an on-chip non-precision oscillator. An on-chip precision oscillator is provided having a known frequency of operation that is within an acceptable operating tolerance. The on-chip precision oscillator is used as a time base and then the period of the on-chip oscillator is measured as a function of the time base. The difference between the measured frequency of the on-chip non-precision oscillator and a desired operating frequency of the on-chip non-precision oscillator is then determined. After the difference is determined, the frequency of the on-chip non-precision oscillator is adjusted to minimize the determined difference.

PLL synthesizer having phase shifted control signals

Abstract: The synthesis of high-frequency signals, such as wireless communication signals, includes a phase-locked loop (PLL) frequency synthesizer with a variable capacitance voltage controlled oscillator (VCO) that has a discretely variable capacitance in conjunction with a continuously variable capacitance The discretely variable capacitance may provide coarse tuning adjustment of the variable capacitance to compensate for capacitor and inductor tolerances and to adjust the output frequency to be near the desired frequency output The continuously variable capacitance may provide a fine tuning adjustment of the variable capacitance to focus the output frequency to match precisely the desired frequency output During fine tuning adjustment, the PLL may be controlled by a plurality of analog control signals The analog control signals may be derived by first generating a plurality of phase shifted signals from a divided version of the VCO output clock by using a shift register The shift register may be clocked by another clock signal at a higher frequency than the divided version of the VCO output clock The phase differences between the plurality of phase shifted signals and a divided version of a reference clock may then be detected and converted to the analog control signals

Digital frequency synthesizer receiver

Abstract: A scanning type frequency synthesized receiver utilizing a voltage controlled oscillator (VCO) for producing a local oscillator signal. The control voltage for the VCO is provided in response to the division rate of a programmable divider. A control circuit programs the divider which control circuit operates to vary the divisor of the divider within a predetermined range as determined by information stored in a memory corresponding to a range of frequencies in a frequency band to be scanned and received by the receiver. Upon a command signal the control circuit operates to vary the divisor of the divider either up or down to cause the frequency of VCO, and thereby the receiver, to scan in a given direction and upon a signal being received the variation of the divider divisor and the receiver scanning is terminated. The VCO can be scanned either up or down in frequency, and the scanning can be either from the upper (or lower) end of a frequency range back to the lower (or upper) end and then reversed or a repetitive scanning from one end of the range to the other in the same direction. In the preferred embodiment disclosed is a multiband scanning receiver in which the stored information for the control circuit corresponds to the extremities of each of a plurality of frequency bands, the information corresponding to a particular band being utilized in response to selection of the band for reception by a band switching means.

A 1.8-V 2.4/5.15-GHz dual-band LCVCO in 0.18-/spl mu/m CMOS technology

Abstract: A dual band, fully integrated, low phase-noise and low-power LC voltage-controlled oscillator (VCO) operating at the 2.4-GHz industrial scientific and medical band and 5.15-GHz unlicensed national information infrastructure band has been demonstrated in an 0.18-/spl mu/m CMOS process. At 1.8-V power supply voltage, the power dissipation is only 5.4mW for a 2.4-GHz band and 8mW for a 5.15-GHz band. The proposed VCO features phase-noise of -135dBc/Hz at 3-MHz offset frequency away from the carrier frequency of 2.74GHz and -126dBc/Hz at 3-MHz offset frequency away from 5.49GHz. The oscillator is tuned from 2.2 to 2.85GHz in the low band (2.4-GHz band) and from 4.4 to 5.7GHz in the high band (5.15-GHz band).

Switched Substrate-Shield-Based Low-Loss CMOS Inductors for Wide Tuning Range VCOs

Abstract: A switched substrate-shield inductor (SSI) topology in bulk CMOS is proposed which minimizes parasitic capacitance and substrate losses, while tuned magnetically induced currents facilitate inductor tunability. The high frequency behavior of the induced current is analyzed, resulting in intuitive insights and design guidelines for a high-performance SSI. An SSI prototype in 65-nm bulk CMOS achieves 34% inductance tunability with a quality factor of >10.3. A voltage-controlled oscillator (VCO) using SSI achieves 40.3% tuning range, from 21 to 31.6 GHz, and a phase noise of −119.1 ± 3.7 dBc/Hz at 10-MHz offset frequencies. The VCO core consumes 4.3 ± 0.2 mW from a 1-V supply.