NCJ Number
210488
Date Published
July 2002
Length
97 pages
Annotation
This report assists law enforcement agencies in evaluating and purchasing audio recorders and body wires.
Abstract
Although a wide variety of audio recorders are available on the market, this assessment focused on solid state audio recorders based on flash memory, because these recorders have no moving parts and do not have background tape hiss or tape speed variations that degrade the fidelity of the recording. Solid state recorders are compared with MP3 recorder/players, mini disc recorder/players, and digital audio tape recorder/players. The assessment of the technology, performance, and future development of these audio recorders concludes that falling prices and larger sizes of flash memory make the solid state recorder a practical piece of law enforcement equipment. Improved "wow" and "flutter," increased immunity from shock and vibration, and the elimination of tape hiss results from the use of flash; however, widespread commercial demand for improved frequency response, high dynamic range, and high signal to noise ratio in small state recorders are not envisioned for the near future. An appendix profiles the major components of a product that could be made to satisfy current law enforcement demands for an audio recorder at a reasonable cost. Regarding body wires, three types cover the majority of products: narrow band FM, digital, and spread spectrum digital. Actual representative products were evaluated for this study, and the strengths and weaknesses of each body wire category were assessed. Performance features considered were voice quality of the received audio, transmission range, battery life, physical disguise, electronic security, and cost. For the body wire systems assessed, cost proved to be a measure of quality. The most significant manufacturer specifications for each feature are provided along with the associated figures of merit. Extensive tables and 4 appendixes with supplementary data and information