A Microwave System for Measurements of AM and FM Noise Spectra

Ondria, J.

doi:10.1109/tmtt.1968.1126784

Cited by 72 publications

(6 citation statements)

References 5 publications

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“…We now turn our attention to the single-oscillator (homodyne) method, in which a frequency discriminator acts as the reference with which the oscillator under test is compared. Systems based on this technique have been in use since the early use of the oscillator metrology, [16][17][18] yet are much older; Pound used a discriminator to stabilize an oscillator. 19 A resonator of quality factor Q is a discriminator that turns frequency fluctuations ␦ into phase fluctuations = ␦ /2 0 Q.…”

Section: Overviewmentioning

confidence: 99%

Photonic-delay technique for phase-noise measurement of microwave oscillators

Rubiola¹,

Salik²,

Huang³

et al. 2005

J. Opt. Soc. Am. B

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A photonic-delay line is used as a frequency discriminator for measurement of the phase noise-hence the short-term frequency stability-of microwave oscillators. The scheme is suitable for electronic and photonic oscillators, including the optoelectronic oscillator, mode lock lasers, and other types of rf and microwave pulsed optical sources. The approach is inherently suitable for a wide range of frequency without reconfiguration, which is important for the measurement of tunable oscillators. It is also insensitive to a moderate frequency drift without the need for phase locking.

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Section: Overviewmentioning

confidence: 99%

Photonic-delay technique for phase-noise measurement of microwave oscillators

Rubiola¹,

Salik²,

Huang³

et al. 2005

J. Opt. Soc. Am. B

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“…The phase noise sideband levels at the DC mixer can be estimated by calculating sideband suppression due to the resonator. Using Ondria’s carrier suppression filter formula (23), the phase noise sidebands at 433 Hz offset from 94 GHz, with a loaded sample resonator Q of 100, are suppressed about 120 dB. The resultant phase noise sidebands reflected from the resonator would be on the order of −173 dBm/Hz for a −3 dBm carrier, which is virtually at room temperature thermal noise and below the noise floor of the LNA.…”

Section: Discussionmentioning

confidence: 99%

Broadband W-band Rapid Frequency Sweep Considerations for Fourier Transform EPR

Strangeway

Hyde

Camenisch

et al. 2017

Cell Biochem Biophys

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A multi-arm W-band (94 GHz) electron paramagnetic resonance (EPR) spectrometer that incorporates a loop-gap resonator (LGR) with high bandwidth is described. A goal of the instrumental development is detection of free induction decay (FID) following rapid sweep of the microwave frequency across the spectrum of a nitroxide radical at physiological temperature, which is expected to lead to a capability for Fourier transform (FT) EPR. Progress toward this goal is a theme of the paper. Because of the low Q-value of the LGR, it was found necessary to develop a new type of automatic frequency control, which is described in an appendix. Path-length equalization, which is accomplished at the intermediate frequency of 59 GHz, is analyzed. A directional coupler is favored for separation of incident and reflected power between the bridge and the LGR. Microwave leakage of this coupler is analyzed. An oversize waveguide with hyperbolic-cosine tapers couples the bridge to the LGR, which results in reduced microwave power and signal loss. Benchmark sensitivity data are provided. The most extensive application of the instrument to date has been the measurement of T1 values using pulse saturation recovery. An overview of that work is provided.

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“…In measuring FM noise, the threshold has been decreased almost a decade by careful alignment of the conventional apparatus augmented by modern ferrite devices. The threshold for a 600-mW signal is 0.0025 measuring system was developed [Ondria, 1968], and a method of measuring the near-carrier noise added by an amplifier was devised [Sann, 1968]. Miscellaneous.…”

Section: A Methods Was Devised For Measuring the Probability Density Fmentioning

confidence: 99%