ABSTRACTS OF TECHNICAL ARTICLES 545 



selective network and then impressing the output voltages upon the 

 grid of a detector. This process is treated analytically and formulas 

 are given which permit the calculation of low-frequency detection 

 products in terms of the transmission characteristic of the distorting 

 network and the maximum frequency shift during modulation. 



Measured detection products produced in such a system are com- 

 pared with values calculated by means of the formulas which are 

 given, and the results are shown to be in substantial agreement over 

 the region in which certain simplifying assumptions are justified. 



Acceptance-Rejection Requirements in Specifications .''^ H. F. Dodge. 

 Specifications for quality of materials and finished products impose 

 requirements for individual quality characteristics to distinguish 

 between what may be considered satisfactory for a given purpose and 

 what may not. For many characteristics, 100 per cent inspection or 

 testing is not feasible; hence reliance must be placed on sampling a 

 part of the whole. Under these conditions, 100 per cent conformance 

 with requirements cannot be achieved with certainty and errors arising 

 from sampling fluctuations cannot be avoided. 



The sampling clauses included in specifications often provide criteria 

 for the acceptance or rejection of lots of a product. These clauses 

 constitute interpretations of the intent of the basic quality require- 

 ments and serve as a basis for action. With sampling, certain risks 

 are assumed by both the consumer and the producer. One kind of 

 risk is discussed, and the relationship between (1) the distribution of 

 the risk between producer and consumer, and (2) the choice of accep- 

 tance criteria and sample size, is indicated for certain conditions. 



Selection and Development of Teachers for Communication Engineering 

 Instruction.^ O. W. Eshbach. One of a symposium of papers pre- 

 sented at the Conference on Electronics and Electrical Communication 

 at the Ithaca meeting of the S. P. E. E. commenting on normal 

 procedure in the selection and training of teachers, the trend of 

 development in instruction in electronics and communication, attitudes 

 characteristic of good teachers, responsibilities toward young in- 

 structors, and the means through which broadening of knowledge may 

 be accomplished. Selection of the right individual, development of 

 effective teaching technique, and the enhancement of knowledge and 

 experience are emphasized as fundamental to successful teaching. 



* Proc. Amer. Soc. for Testing Materials, Vol. 34, Part II, 1934. 

 ^ Jour. Engg. Education, April, 1935. 



