Methods are shown for measuring crosstalk and inductive voltage drop along conductors, trace current paths on conducting planes, measure currents, and inject precisely controlled amounts of noise into a circuit. Data is presented in this paper to illustrate usage of some of these methods. L OOP O PERATION Equivalent Circuit A variety of measurement techniques have been developed to meet various requirements for phase noise measurements. The three most widely-adopted techniques are: direct spectrum, phase detector and two-channel cross-correlation. The model presented here applies to both optical and optoelectronic noise figure measurement techniques. Reduced to its simplest form, it is shown to be consistent with the noise figure as defined by the IEC SC86C, Working Group 3 , the international standards bodyŽ. responsible for optical amplifier noise figure definitions. Index Terms Didactic Materials, Measurement Techniques, Musical Vibrations, Noise. INTRODUCTION Advances in technology have resulted in an increase in the amount of unwanted sound, which we call noise. The control of noise and vibrations is an important purpose for manufacturers and mechanical engineers, as the public's demand for quiet measurement and monitoring as far as possible, the equipment specification and the measurement procedures are subjected to national and international standards of various severity depending on the application. (see Instrumentation for Noise Measurement) 2. Basis of Sound The following text shortly presents an overall picture of engineering Measurements shall not be made if wind velocity is > 3 m/s . It shall be ensured that the results are not affected by gusts of wind. 5.3. Background Noise Background noise shall be measured by the microphone located at the driver's seat of stationary vehicle, which shall be lower than the measured test value by 10 dB(A). A suitable windscreen as The person making the measurement must understand: The purpose of measurement: compliance with noise regulations, hearing loss prevention, noise control, community annoyance etc. The sources of noise, and times when the sources are operating. The temporal pattern of noise - continuous, variable, intermittent, impulse. Locations of exposed persons. Fortunately, phase noise techniques can measure jitter with excellent sensitivity. Jitter measurements well below 10 femtoseconds (1 fs = 10-15 s) are possible, which is much more sensitive than a typical oscilloscope. To get this level of sensitivity the cost of a phase noise analyzer is almost two orders of magnitude lower. If we may assume an equal noise contribution of each oscillator, the phase noise of the DUT is the measured phase noise minus 3 dB. Residual phase noise of the test bench may also affect the measured phase noise mainly at noise floor level. It is why test bench makers propose multi channel measurements and/or cross correlation techniques in order The results of a comprehensive noise measurement survey of port related noise sources impacting schools and residences in the Community are presented along with preliminary conclusions and findings. The next step will be to use the data from the measurement survey to develop noise impact criteria and noise zone maps. these aspects are dealt with is two sections, organized as follows: a) review of transducers and measurement set-ups of participants, including limitations and experiences; b) review of either