George S.K. Wong and Tony F.W. Embleton, Editors
American Institute of Physics, 500 Sunnyside Blvd, Woodbury, NY 11797, USA
321 pp., hard cover, 1995. USD 85.00
This text is the third in a series of books on modern acoustics and signal processing published by the American Institute of Physics. As its title indicates, it is devoted to the condenser microphone. The book opens with a history of the condenser microphone and the history of the Western Electric 640AA capacitance microphone. The following chapters cover the theory of condenser microphones, calibration methods, (free-field, reciprocity, and diffuse field calibrations), and calibration methods employed by national testing laboratories, including those in Japan, the United States, the United Kingdom, Germany, and Canada.
The book also deals with secondary calibration methods which are widely used in the field. These include comparison methods, calibration at high amplitudes, the use of the electrostatic actuator. Additional chapters deal with determination of the phase match of microphones and the practical aspects of handling and caring for these devices. The last chapter is devoted to the characteristics of commercially-available microphones, the data being supplied by the manufacturers.
The FBI appears to have begun using a novel form
The FBI appears to have begun using a novel form of electronic surveillance in criminal investigations: remotely activating a mobile phone\\\'s microphone and using it to eavesdrop on nearby conversations.
The technique is called a \\\"roving bug,\\\" and was approved by top U.S. Department of Justice officials for use against members of a New York organized crime family who were wary of conventional surveillance techniques such as tailing a suspect or wiretapping himthe eavesdropping technique \\\"functioned whether the phone was powered on or off.\\\" Some handsets can\\\'t be fully powered down without removing the battery; for instance, some Nokia models will wake up when turned off if an alarm is set