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.

Receiver for terrestrial AM and satellite FM-TV broadcasting signals

Abstract: Receiver for terrestrial AM and satellite FM-HF-TV signals in first and second frequency ranges, respectively, of mutually predominantly equal dimensions, which succeed each other in frequency, comprising, arranged one after the others, a HF-AM-FM section (2-6), a mixing circuit (8) common for the AM and FM-TV signals and an IF device (10-20), oscillator mixing signals being applied from a tuning oscillator (9) to that mixing circuit for a frequency conversion of the AM and FM-HF-TV signals into a first AM and an FM intermediate frequency signal, respectively, having a first AM and an FM intermediate frequency, of which at least the first AM intermediate frequency is located above the first frequency region In order to enable a simple and cheap realisation, in which a tuning oscillator having a comparatively narrow-band tuning range can be used, the first AM intermediate frequency is of the order of magnitude of twice the highest frequency of the first frequency range and the FM intermediate frequency is of the order of magnitude of half the lowest frequency of the second frequency range, the IF-device including an AM (13-19) and a FM-IF (10,11) section whose inputs are coupled to an output of the mixing circuit for a separate selection and processing of the first AM and the FM-intermediate frequency signal respectively

Radio receiver for mobile reception with sampling rate oscillator frequency being an integer-number multiple of reference oscillation frequency

Abstract: Digital tuning of a locally generated frequency supplied to a frequency converting mixer, a mobile radio receiver is provided with great economy of components by utilizing the sampling rate oscillator for an analog-to-digital converter provided at the output of an analog intermediate frequency amplifier of the receiver as the source of the difference frequency for a phase locked loop (PLL) for control of the phase of a local oscillator for the mixer or mixers. All frequencies used to supply local oscillations to mixers, as well as the operating frequency of the phase locked loop are integer number multiples of the sampling rate pulse generator. Some division stages have fixed dividers and others have divisors selectable by a tuning processor and in some of the divisor connections it is useful to interpose a fixed or selectable-factor multiplier. A sampling rate of 42.75 MHz is recommended and an intermediate frequency amplifier frequency which is a rational number multiple of 57 kHZ, preferably 10.6875 MHz are similarly recommended.

Phase-locked carrier-envelope-offset frequency at 1560 nm.

Abstract: We report on the measurement of an Erbium-fiber oscillator’s carrier-envelope-offset frequency using an extruded SF6 photonic crystal fiber for the generation of a more than two octave-spanning supercontinuum from 400 nm to beyond 1750 nm. A modified type of f-2f-interferometer was employed, beating the frequency doubled input signal of the fiber oscillator with the supercontinuum to generate the carrier-envelope-offset beat. Controlling the fiber oscillator’s pump power with an electronic feedback loop, we phase-locked the carrier-envelope-offset frequency to an external reference source. The resulting residual phase excursions correspond to fractional frequency instabilities of the oscillator’s frequency comb of the order of 10-16 for averaging times longer than 10 s.

CW ultrasonic bolt tensioning monitor

Abstract: This invention is a CW ultrasonic device for measuring frequency shifts of the peak of a mechanical resonance in a body. One application of the device is measuring the strain in a bolt. It also has other applications such, for example, as measuring the thickness of a body, measuring the depth of a flaw in a body, measuring the elongation of body and measuring changes in velocity of sound in a body. The body is connected, by means of a CW transducer, to electrical circuit means including a narrow band RF amplifier to form a closed loop feedback marginal oscillator that frequency locks the device to the peak of a mechanical resonance in the body. Thereafter, when the frequency of this peak changes, because of a physical change in the body, the frequency of the oscillator changes. The device includes an automatic frequency resonant peak tracker that produces a voltage that is related to a change in frequency of the oscillator. This voltage is applied to the RF amplifier to change the center of its frequency band to include the frequency of the peak and is a measure of the frequency shift. The device also includes a special transducer which requires contact to only one side of the body and provides high electrical isolation between its parts.