Abstract: A heterodyne interferometric optical fiber displacement sensor using a laser diode. The frequency and the intensity of the laser diode beam are periodically modulated by an injection current. The laser diode beam is routed to a rod lens via a first optical fiber, an optical fiber coupler, and a second optical fiber. The interference light resulting from the interference between the light reflected from the exit surface of the rod lens and the light reflected from an object surface is routed to a third optical fiber via the optical fiber coupler, which is then detected by a photodiode attached to the end of the third optical fiber. From the output of the photodiode, a given frequency component is extracted using a bandpass-filter. The extracted signal is converted into a pulse signal. The frequency change of the pulse signal (equivalent to a doppler frequency shift caused by the movement of the object surface) is accumulated using an electronic circuit.

Abstract: A method and apparatus for real time speech recognition with and without speaker dependency which includes the following steps. Converting the speech signals into a series of primitive sound spectrum parameter frames; detecting the beginning and ending of speech according to the primitive sound spectrum parameter frame, to determine the sound spectrum parameter frame series; performing non-linear time domain normalization on the sound spectrum parameter frame series using sound stimuli, to obtain speech characteristic parameter frame series with predefined lengths on the time domain; performing amplitude quantization normalization on the speech characteristic parameter frames; comparing the speech characteristic parameter frame series with the reference samples, to determine the reference sample which most closely matches the speech characteristic parameter frame series; and determining the recognition result according to the most closely matched reference sample.