Frequency drift

About: Frequency drift is a research topic. Over the lifetime, 5054 publications have been published within this topic receiving 56191 citations. The topic is also known as: chirp rate.

Frequency synthesizer and high-speed automatic calibration device therefor

Abstract: A frequency synthesizer and an automatic calibration device are disclosed. An automatic calibration device for a phase-locked loop based frequency synthesizer includes: a frequency-to-digital converter for converting a frequency of a signal outputted from a voltage controlled oscillator into a first digital value; a frequency difference detector for calculating a difference between the first digital value outputted from the frequency-to-digital converter and a second digital value corresponding to a target frequency; an automatic frequency calibration logic for selecting an optimal control code for a capacitor bank such that an output frequency of the voltage controlled oscillator is closer to the target frequency; and a loop bandwidth calibration logic for tuning a charge pump gain such that a loop bandwidth is kept constant in the optimal control code using the frequency-to-digital converter. Thus, the calibration speed can be increased, and the loop bandwidth can be kept constant within the output frequency range.

Oscillator with switchable filter control voltage input for rapidly switching to discrete frequency outputs

Abstract: A voltage controlled oscillator controllable to discrete frequency outputs, which outputs are applied to a phase detector through divider circuits and compared to a reference signal of the same frequency, is controlled to discrete frequency outputs by variable voltages or variable width pulses, proportional to the difference in phase between the two signals, from the phase detector which pulses are applied to the oscillator through loop filters. Each loop filter is an RC circuit which integrates the pulses and serves as a memory to retain a relatively constant voltage thereacross. Therefore, when a specific loop filter is switched into the circuit the voltage controlled oscillator is rapidly switched to a discrete frequency output proportional to the voltage stored in the loop filter.

A superregenerative receiver for phase and frequency modulated carriers

Abstract: This paper presents a new superregenerative receiver architecture. This receiver uses an oscillator based on a transmission line. By periodically changing the oscillator pole locations, the receiver is able to translate the carrier phase information into a low-pass signal. This circuit may also be used as a band-pass sampler for low-level RF signals.