Influence of condenser microphones on phase measurements in photoacoustics at low pressure

1986 ◽  
Vol 64 (9) ◽  
pp. 1111-1115
Author(s):  
G. Louis ◽  
F. Lepoutre ◽  
J. P. Monchalin
Keyword(s):  
Phase Shift ◽  
Photoacoustic Signal ◽  
Low Pressure ◽  
Response Magnitude ◽  
Phase Measurements ◽  
Condenser Microphone ◽  
Slip Effects ◽  
Shift Response ◽  
Lumped Parameters

Condenser microphones used as photoacoustic signal detectors exhibit a phase-shift response that depends on both the nature and the pressure of the ambient filling gas. In this paper, we develop a lumped-parameters model of the microphone damping in which the approximations are thoroughly discussed. This model, after taking into account gas-slip effects on the surfaces of the condenser cartridge plates, is shown to accurately describe the response (magnitude and phase) of a commercial condenser microphone (Brüel and Kjaer 4144) for frequencies below 2.2 kHz and ambient pressures between 1.5 × 103 and 6 × 104 Pa.

Direct phase measurements in phase-shift masks

1992 ◽  
Author(s):  
Amalkumar P. Ghosh ◽  
Derek B. Dove
Keyword(s):  
Phase Shift ◽  
Phase Measurements

MONOFREQUENCY BOREHOLE TRAVELTIME SURVEY

Geophysics ◽  
1977 ◽  
Vol 42 (6) ◽  
pp. 1137-1145 ◽  
Author(s):  
R. W. Ward ◽  
M. R. Hewitt
Keyword(s):  
Phase Shift ◽  
Measurement System ◽  
Phase Measurement ◽  
Compressional Wave ◽  
Computer Processing ◽  
Surface Source ◽  
Efficient Operation ◽  
Phase Measurements ◽  
Novel Technique ◽  
The Difference

A novel technique was successfully tested to measure compressional‐wave traveltime from a vibrator surface source, using monofrequency pilot signals, to a borehole seismometer. The difference between traveltime measurements by a direct‐phase‐measurement system and those obtained by computer processing of the digitally recorded monofrequency signals was a fraction (0.2 − 0.3) of a millisecond. Absolute monofrequency traveltime measurements obtained by adding integral numbers of signal cycles to phase measurements were not consistent for two different frequencies at the same depth. The suspected cause of this inconsistency is a frequency‐dependent phase shift, due to vibrator‐earth coupling, between the baseplate accelerometer and the borehole seismometer. However, adjustment of the two monofrequency (35 Hz and 55 Hz) traveltime surveys to match the check‐shot traveltime to the 600 ft depth produced excellent agreement between the two monofrequency traveltime surveys and the check‐shot traveltimes. After adjustment, the rms traveltime difference between the 35 Hz survey and the check‐shot survey was 2.5 msec and between the 55 Hz survey and the check‐shot survey was 1.3 msec. Several possible advantages of this technique include the use of a source which is more acceptable in some environments, ability to obtain a digital traveltime reading in the field, and more efficient operation than conventional surveys.

scholarly journals Linear Phase Shift Response with High Dynamic Range for Holographic Recording in As2S3

1994 ◽  
Vol 1 (1) ◽  
pp. 36-38 ◽  
Author(s):  
Christoph H. DIETRICH ◽  
Steffen NOEHTE ◽  
Reinhard MANNER ◽  
Kurt K. SCHWARTZ
Keyword(s):  
Phase Shift ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Holographic Recording ◽  
Linear Phase ◽  
Shift Response ◽  
High Dynamic

Time-Reversal Symmetry Breaking at Grain Boundaries in d-Wave Superconductors

1997 ◽  
Vol 11 (09) ◽  
pp. 1113-1136 ◽  
Author(s):  
A. B. Kuklov ◽  
Manfred Sigrist
Keyword(s):  
Phase Shift ◽  
Grain Boundary ◽  
Crystal Lattice ◽  
Time Reversal ◽  
Josephson Effect ◽  
Landau Theory ◽  
Time Reversal Symmetry ◽  
Ginzburg Landau ◽  
Flux Quantization ◽  
Slip Effects

Crystal lattice distortion can generate a superconducting state which breaks locally time-reversal symmetry by yielding a coupling between order parameters of different symmetry. The problem of a twist in the crystal lattice at a boundary between differently oriented grains is investigated by means of a generalized Ginzburg–Landau theory. It is shown that under certain conditions a time-reversal breaking state appears at the grain boundary. This state leads to a nontrivial phase shift in the Josephson effect across the grain boundary. This phase shift can be observed through a modified flux quantization (fractional fluxes) and phase slip effects.

Phame: phase measurements on 45nm node phase shift features

2008 ◽  
Author(s):  
Ute Buttgereit ◽  
Robert Birkner ◽  
Dirk Seidel ◽  
Sascha Perlitz ◽  
Vicky Philipsen ◽  
...  
Keyword(s):  
Phase Shift ◽  
Phase Measurements

Relationship between amplitude and phase measurements of photoacoustic signal in the infrared region and water concentration in condensed milk

1990 ◽  
Vol 57 (3) ◽  
pp. 393-400 ◽  
Author(s):  
Richard Martel ◽  
Paul Paquin ◽  
Lionel Bertrand
Keyword(s):  
Near Infrared ◽  
Water Concentration ◽  
Photoacoustic Signal ◽  
Infrared Region ◽  
Phase Information ◽  
Water Determination ◽  
Phase Fluctuations ◽  
Phase Measurements ◽  
Condensed Milk ◽  
Near Infrared Region

SummaryPhotoacoustic signals in the near infrared region (~ 2·75 μm) have been investigated using amplitude and phase information to determine their effectiveness in estimating the water content of milk. The results obtained showed a good correlation between the photoacoustic signal and water concentration (R2 = 0·98) even though photoacoustic saturation was present in the range of wavelengths studied. However, this is not recommended as a fast technique for water determination because of inherent phase fluctuations in the samples analysed.

Interferometer for phase measurements in phase-shift masks

1993 ◽  
Author(s):  
Derek B. Dove ◽  
T. C. Chieu ◽  
Amalkumar P. Ghosh
Keyword(s):  
Phase Shift ◽  
Phase Measurements
Sign in / Sign up

Export Citation Format

Share Document