Abstract:
A method, an apparatus, and a computer program product are provided. The apparatus outputs a sinusoidal signal according to a first clock frequency, generates, a first digital signal having a 25% duty cycle based on the sinusoidal signal, generates a second digital signal having a 25% duty cycle based on the sinusoidal signal, combines the first digital signal and the second digital signal to generate a combined digital signal having a 50% duty cycle and a second clock frequency that is double the first clock frequency, and doubles the second clock frequency of the combined digital signal to generate an output signal having a third clock frequency that is quadruple the first clock frequency. The apparatus further generates a first control voltage and a second control voltage for the first buffer and a third control voltage for the second buffer based on the output signal.
Abstract:
A two-walled coupled inductor includes an outer wall and an inner wall separated by a slit. The outer wall has a first width and the inner wall has a second width The inner wall and the outer wall may be configured to be coupled to oscillator circuitry. The two-walled coupled inductor may include an electrically conductive stub coupled to the outer wall to be coupled to a power supply. A common mode current flows through the outer wall, and the stub if one is present, and a differential mode current flows through both the outer wall and the inner wall, but not the stub. The first and second widths, and dimensions of the stub, may be sized to increase an inductance of the common mode compared to an inductance of the differential mode, thereby reducing phase noise of the inductor-based resonator.
Abstract:
A differential crystal oscillator circuit, including: first and second output terminals; a cross-coupled oscillation unit including first and second transistors cross-coupled to the first and second output terminals; first and second metal-oxide semiconductor field-effect transistor (MOSFET) diodes, each MOSFET diode including a resistor connected between gate and drain terminals, wherein the first MOSFET diode couples to the first transistor to provide low-impedance load at low frequencies and high-impedance load at higher frequencies to the first transistor, wherein the second MOSFET diode couples to the second transistor to provide low-impedance load at low frequencies and high-impedance load at higher frequencies to the second transistor; and a reference resonator coupled between the first and second output terminals to establish an oscillation frequency.
Abstract:
An apparatus includes a main amplifier configured to receive an input signal. The main amplifier is also configured to generate an output signal. The apparatus also includes an auxiliary path configured to phase-shift the input signal to generate a cancellation signal to reduce or cancel a blocker component of the output signal.
Abstract:
A method and apparatus are disclosed for filtering a signal, such as a transmit communication signal with a configurable notch filter. The configurable notch filter may attenuate a set of frequencies near a selected notch frequency. In some embodiments, the configurable notch filter may include a variable resistor, a variable capacitor, a first inductor, and a second inductor. The variable resistor may be configured to compensate for resistive losses within the configurable notch filter. The variable capacitor may be configured to determine the set of frequencies to be attenuated.
Abstract:
Certain aspects of the present disclosure provide techniques and apparatus for generating multiple oscillating signals. One example circuit generally includes a first voltage-controlled oscillator (VCO) having a first inductor and a second VCO having a second inductor in parallel with a third inductor, wherein the second and third inductors are disposed inside a loop of the first inductor and may behave as a magnetic dipole. The loop of the first inductor may be symmetrical, and a combined geometry of loops of the second and third inductors may be symmetrical. The coupling coefficient (k) between the first inductor and a combination of the second and third inductors may be small (e.g., k
Abstract:
An apparatus includes a main low noise amplifier and an auxiliary low noise amplifier. The auxiliary low noise amplifier is coupled in parallel with the main low noise amplifier. The auxiliary low noise amplifier includes a common source degeneration resistor.
Abstract:
A two-walled coupled inductor includes an outer wall and an inner wall separated by a slit. The outer wall has a first width and the inner wall has a second width. The inner wall and the outer wall may be configured to be coupled to oscillator circuitry. The two-walled coupled inductor may include an electrically conductive stub coupled to the outer wall to be coupled to a power supply. A common mode current flows through the outer wall, and the stub if one is present, and a differential mode current flows through both the outer wall and the inner wall, but not the stub. The first and second widths, and dimensions of the stub, may be sized to increase an inductance of the common mode compared to an inductance of the differential mode, thereby reducing phase noise of the inductor-based resonator.
Abstract:
A differential crystal oscillator circuit, including: first and second output terminals; a cross-coupled oscillation unit including first and second transistors cross-coupled to the first and second output terminals; first and second metal-oxide semiconductor field-effect transistor (MOSFET) diodes, each MOSFET diode including a resistor connected between gate and drain terminals, wherein the first MOSFET diode couples to the first transistor to provide low-impedance load at low frequencies and high-impedance load at higher frequencies to the first transistor, wherein the second MOSFET diode couples to the second transistor to provide low-impedance load at low frequencies and high-impedance load at higher frequencies to the second transistor; and a reference resonator coupled between the first and second output terminals to establish an oscillation frequency.
Abstract:
A method and apparatus for charging a crystal oscillator are provided. A voltage generating module outputs a ramp voltage signal to a ring oscillator. The ring oscillator generates and outputs a waveform based on the ramp voltage signal. The ramp voltage signal facilitates the ring oscillator to output the waveform at a frequency that varies with time, wherein the varying frequency is within a frequency range of the crystal oscillator. An inverter generates a digital input signal based on the waveform. The digital input signal is sent to an input of the crystal oscillator for charging the crystal oscillator. A feedback module outputs a feedback signal based on the digital input signal, wherein the feedback signal controls the voltage generating module to generate a fixed voltage signal that facilitates the ring oscillator to output the waveform at a frequency that is equal to a resonance frequency of the crystal oscillator.