High-fidelity lightwave transmission of multiple AM-VSB NTSCsignals

The progress towards developing AM lightwave links for the transmission of multiple TV signals is reported. While the signal-quality objectives and transmission distances are appropriate for CATV trunking, the technology is expected to have applicability to the distribution of video signals in the subscriber loop. Highly linear 1.3-μm distributed feedback (DFB) lasers designed expressly for analog requirements are used to transmit 42 continuous wave carriers according to the standard US CATV frequency plan. For the best lasers, when evaluated over 12 km of fiber, carrier to noise was >52 dB, composite second-order distortion was >70 dBc, and composite triple beat was >70 dBc. The relationship between measurements with continuous wave carriers and actual video signals is discussed. System design rules are offered. Properties that lead to superior analog performance are discussed. Data from 700 links indicate that composite third-order distortion generally scales with product count but that composite second-order distortion has a significant frequency-dependent component     

Rehabilitation services as ideology: A response to Stubbins, Coudroglou, and Berkowitz.

Responds to the comments of J. Stubbins (see record 1985-31779-001), A. Coudroglou (see record 1985-31754-001), and E. Berkowitz (see record 1985-31749-001) on needed reforms of the rehabilitation service system. With emphasis on Stubbins's comments, it is argued that Stubbins makes sweeping unsupported generalizations and that he overlooks the strengths derived from the legislative process, the disability rights movement, and rehabilitation research. Although reform is needed, it is suggested that it will come through informed inquiry and a changing environment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Opportunities for psychologists in disability research.

Reviews research contributions that have been beneficial to disabled citizens including work on the helping relationship, contingencies of reinforcement, vocational rehabilitation, assessment scales, and family adjustment. Support by the federal government for future research will be guided by goal statements that address the refinement of assessment instruments, the psychological effects of childhood disability, the effects of aging on the physically disabled, the psychosocial impact of disabilities in minority groups, and improved service delivery strategies. (23 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)