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.

Equivalent time sampler using an oscillator

Abstract: An equivalent time sampler uses an oscillator for sampling an input waveform having a repetitive component. A periodic signal is derived from the input waveform, and an offset frequency is derived from the periodic signal. The periodic signal and offset frequency are input to an offset locked oscillator to generate a sampling frequency that is the combination of the periodic signal and the offset frequency. The sampling frequency is used to obtain a sample of the input waveform for each acquisition cycle of the waveform.

Integrated circuit and receiving device

Abstract: Dispersing directions of oscillation frequency variable ranges of all voltage controlled oscillators provided in an integrated circuit are uniformed, and not only a range covering a frequency regardless of whether a dispersion occurs or not, but also a range covering the frequency only in a case where the dispersion occurs is used as the frequency variable range of the voltage controlled oscillator, and the frequency variable ranges of the voltage controlled oscillators are set so as to be successive with respect to each other, so that a small number of voltage controlled oscillators can cover a wide frequency variable range. Thus, the integrated circuit having voltage controlled oscillators therein is miniaturized.

Channel selection device

Abstract: A reference signal frequency is generated for selection of a desired channel by a frequency sweep circuit comprising two sweep oscillators. The operations of the oscillators are reversed with each other at a predetermined frequency interval, and a voltage sweep main circuit and a voltage sweep sub-circuit are provided to apply a control voltage to a variable capacitance diode. The diode is contained in a tuner to control the sweep operation by the voltage sweep circuits in response to the reference frequency for channel selection.

Method and apparatus for decreasing channel spacing in digital frequency synthesizers

Abstract: A method and apparatus for digital frequency synthesis is provided which enables the channel spacing of a digital synthesizer to be decreased below a reference frequency. The frequency clock output of a voltage controlled oscillator is digitally divided by an average multiple which may be other than a whole number. The output of the divider forms the input to a digital phase comparator which compares the phase of the reference frequency and the input or feedback frequency and generates a signal output that has a duty cycle proportional to the phase difference between the reference and feedback frequencies. The last mentioned output signal eventually is used to bias the voltage controlled oscillator to the proper output frequency so that the feedback and reference frequencies have a constant phase difference. Since the average multiple of the divider can be varied fractionally, a plurality of output signals from the voltage controlled oscillator are obtainable which have frequency spacing between them of some frequency less than the reference frequency.

High Frequency Model of Transformer Winding

Abstract: A high frequency model of transformer winding is used to analyze the voltage oscillations due to various excitations such as the very fast transient overvoltage which occurs at the time of disconnecting switch operations. Usually, a circuit of interlinked inductances and capacitances is used for this purpose, in which circuit parameters have to be properly determined. Previously, those constants have been estimated taking the coil section pair as a unit. In the method proposed here, the section pair can be further subdivided. The time-domain calculation is conducted combining the frequency analysis and FFT technique. The voltage oscillations of the winding subjected to the lightning impulse are calculated. The correspondence with the experimental results is satisfactory. The response to a chopped impulse shows this method's applicability to high frequency analysis. Since the constants are calculated directly from the design parameters of transformer winding, this technique is particularly useful in developing and designing transformers. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 146(3): 8–16, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10280