Method and apparatus for frequency spectrum analysis

A method for frequency spectrum analysis of an unknown signal in real-time is discussed. The method is based upon integration of 1-bit samples of signal voltage amplitude corresponding to sine or cosine phases of a controlled center frequency clock which is changed after each integration interval to sweep the frequency range of interest in steps. Integration of samples during each interval is carried out over a number of cycles of the center frequency clock spanning a number of cycles of an input signal to be analyzed. The invention may be used to detect the frequency of at least two signals simultaneously. By using a reference signal of known frequency and voltage amplitude (added to the two signals for parallel processing in the same way, but in a different channel with a sampling at the known frequency and phases of the reference signal), the absolute voltage amplitude of the other two signals may be determined by squaring the sine and cosine integrals of each channel and summing the squares to obtain relative power measurements in all three channels and, from the known voltage amplitude of the reference signal, obtaining an absolute voltage measurement for the other two signals by multiplying the known voltage of the reference signal with the ratio of the relative power of each of the other two signals to the relative power of the reference signal

Comparative analysis of the seismic hazard of Central China

Seismic hazard assessment is globally recognised as a tool in identifying levels of earthquake ground shaking within an area. However, methodologies for seismic hazard calculation are wide ranging and produce variations in results and maps. As a case study seismic hazard and results from Gumbel’s method of extremes are determined for the area of greatest intraplate seismicity in China covering the provinces of Gansu, Sichuan and Yunnan. This area is termed the North-South Seismic Zone. Devastating earthquakes in this zone include the 8.4 MS 1920 Haiyuan earthquake causing over 220,000 deaths and the 1996 Lijiang earthquake. Most recently the 2008 Wenchuan earthquake caused over 69,000 deaths with more than 18,000 people missing. These results and seismic hazard maps are compared with the publicly available maps of GSHAP and the national seismic hazard map of China at the level of 10% probability of exceedance in a 50 year period. The distributions of high and low hazard areas are similar and adjacent to the major thrust and strike-slip faults dominating in this area. However, results from the Gumbel method of extremes suggest that the hazard levels within certain areas are slightly different compared to the other two models. This is primarily because the Gumbel methodology is based on determining hazard from earthquakes that have already taken place whereas the other two models determine maximum hazard levels in areas which may exhibit no previous strong hazard. Additionally the Chinese national hazard map does not indicate levels of ground shaking intensity greater than IX in detail, whereas such zones are identified using the extreme value method. This work should be used to strengthen the seismic hazard analysis of this area of China

A Michelson interferometer for detecting grating table rotation

Michelson interferometer to detect grating table rotation in infrared spectromete

Inorganic glass ceramic slip rings

Prototypes of slip rings have been fabricated from ceramic glass, a material which is highly resistant to deterioration due to high temperature. Slip ring assemblies were not structurally damaged by mechanical tests and performed statisfactorily for 200 hours

Friction measuring apparatus Patent

Kinetic and static friction force measurement between magnetic tape and magnetic head surface

Melodia : A Comprehensive Course in Sight-Singing (Solfeggio)

Melodia is a 1904 book designed to teach sight-singing. The educational plan is by Samuel W. Cole; the exercises were written and selected by Leo R. Lewis. Melodia is presented here as a complete edition and has also been divided into its four separate books.https://scholarworks.sjsu.edu/oer/1000/thumbnail.jp

Comment on some proposed mechanisms for attenuation of third sound

Two explanations have been proposed for an apparent discrepancy between theoretical prediction and experimental measurement of third-sound attenuation. One of these proposes a new "macroscopic quantum uncertainly principle," and the other proceeds via nonlinear, anharmonic effects due to zero-point fluctuations. We argue that neither suggestion is acceptable