Dual differential LC voltage-controlled oscillator

A circuit comprising:

• an amplifier having an input terminal and an output terminal, wherein the amplifier is configured to i) amplify a signal at the input terminal and ii) provide an oscillating signal at the output terminal;
• and
• an impedance element having an inductive element and a capacitive element, the impedance element coupled between the input terminal and the output terminal of the amplifier, wherein the capacitive element comprises:
• a first variable capacitor coupled to receive a first differential control voltage, the first differential control voltage i) setting a capacitance of the first variable capacitor and ii) providing a first level of adjustment to an oscillation frequency of the oscillating signal, and
• a second variable capacitor coupled to receive a second differential control voltage, the second differential control voltage i) setting a capacitance of the second capacitor and ii) providing a second level of adjustment to the oscillation frequency of the oscillating signal, wherein the first and second levels of adjustment are different.

Apparatus for generating an oscillating signal, the apparatus comprising:

• an amplifier having an input terminal and an output terminal, wherein the amplifier provides a differential oscillating signal at the output terminal;
• and
• an inductor-capacitor (LC) tank coupled between the input terminal and the output terminal of the amplifier, wherein the LC tank comprises an inductive element coupled in parallel with a capacitive element, and wherein the capacitive element comprises:
• a first varactor pair coupled to receive a first differential control voltage, wherein the first differential control voltage i) sets a capacitance of each varactor of the first varactor pair and ii) provides a first level of adjustment to an oscillation frequency of the oscillating signal, and
• a second varactor pair coupled to receive a second differential control voltage, wherein the second differential control voltage i) sets a capacitance of each varactor of the second varactor pair and ii) provides a second level of adjustment to the oscillation frequency of the oscillating signal, wherein the first and second levels of adjustment are different.