It is well known that exceptions are allowed in generics. Concerning this widely-agreed-upon phenomenon of exceptions in generics, Cohen (2004) argues that exceptions are allowed only if “homogeneity” is not violated. That is, the exceptions should not form a salient “chunk” of the domain of the generic. For this, he proposes two ways of mapping of cognitive mental representations, namely, “tree” and “geometric” representations. It will be argued in this paper, however, that choices between these two mental representations claimed to be involved in the interpretation process of generics are quite arbitrary, and that counterexamples also exist for the “homogeneity” requirement. Given this, the main purpose of this paper will be to discuss the problems of Cohen’s theory. Its other purpose will be to try to delve into the fundamental issue of the meaning of generics, and to suggest that generics, similar to metaphors, involve cognitive conceptualizations based on the language users’ encyclopedic knowledge, world knowledge from experiences, common sense, beliefs, stereotypes, prejudices, etc.

A linear power amplifier is particularly emphasized on the system using a linear modulations, such as 16QAM and QPSK with pulse shaping, because intermodulation distortion which causes adjacent channel interference and co-channel interference is mostly generated in a nonlinear power amplifier. In this paper, parameters of a linearization loop, such as an amplitude imbalance, a phase imbalance and a delay mismatch, are briefly analyzed to get a specific cancellation performance and linearization bandwidth. Experimental results are presented for IMT-2000 frequency band. The center frequency of the feedforward amplifier is 2140 MHz with 60 MHz bandwidth. When the average output power of feedforward amplifier is 20 Watt, the intermodulation cancellation performance is more than 21 dB. In this case, the output power of feedforward amplifier reduced 3.5 dB because of extra delay line loss and coupling loss. The feedforward amplifier efficiency is more than 7.2 % for multicarrier signals, 59 dBc for ACPR.